OverUnity Research

Gentlemen  

Here we will be exploring the breaking of molecular bonds in "water" through vibrational reaction".

Various members of this forum have been working aside on this idea, in reality it is not new, it all started back in the 1930's with Dr. Royal Rife, then in the 1970's Dr. Andrija Puharich, and more recently Kanzius with his burning of salt water. What do they all have in common?

They were all working to find a cure for cancer by manipulating the structure of the cancer cells and were using the basic recipe from the start of RF in a type of chaos to vibrate the molecules within those cells.

Rife was relatively low power and so was Puharich to start with until he found out what was happening, his higher power system was never published but he did patent the basics which showed the efficiency of using a type of modulated RF. Now in the turn of the century Kanzius working in the same field of a cancer cure, was also using RF at high power levels, 300watts RF. He found also by accident that it would dissociate salt water and be able to burn the gas. As Kansius had his setup he was only able to reach just under a COP of 1, on the other hand Puharich with his low power was able to just obtain a little over a cop of 1.

All these systems use RF modulated in one form or another to create a form of "chaos", multiple frequencies, some of which multiply their power due to being generated from different angles and add together their power ( harmonics and heterodyning creating the same frequencies multiple times ).

This is chaos SEE LINK BELOW

This is the RF power unit we have at the moment, which when powered up to it's full power (increasing the voltage input) should deliver in excess of 400w @ around 90% efficiency. We are working on the modulation and delivery system at the moment. Here is the video.-

from itsu
https://www.youtube.com/watch?v=nJTchos3opU&feature=youtu.be

Active participation and comments are encouraged ,In the Theme of this forum ..
all is open source and not for sale...

respectfully
Chet K

Thank you Chet for starting this research thread, no claims just pure research and experimentation.

I would advise anyone who wants to participate, to read up on Royal Rife's work (there is a lot, just look at the basics), Andrija Puharich and his patent found here:- http://www.rexresearch.com/puharich/1puhar.htm

and what little you can find on Kanzius (a lot was suppressed it seems), there are mainly a couple of videos on youtube and a few write ups not giving anything away ( I am told on good authority that it is now used in an advanced form by the US navy).

Here we are trying to find and implement the correct and most efficient way to break the water molecule by looking at the last 85 years, or so, of work done by others in molecular bond breaking using RF in a special way, a way that can be reproduced time and time again.

The above three names are not the only ones, but probably the ones that stick out more than others. I have not mentioned Meyer as I don't want to mix up what people see as electrolysis with what we are doing here, which is not electrolysis.

Regards

Mike 8)

Nice video Itsu, and your circuit performs well.

What im thinking here is we need a frame of reference , should you or anyone be successful in spliting/breaking the bond of the water molecule, to measure output for input against. As I already spent time and money on an accurate measuring device when I was interested in Les' s thread, and have a very efficient dry cell, I could set the bench mark for standard DC electrolysis as far as MMW go's.

@Itsu

Why not use a 2 plate cell as a dummy load. This way you wont miss anything while your testing.
You will have to rectify the RF out though, and your resistance can be adjusted by your Elite mix.

Thanks Tinman,

Sounds logical to have a reference yes, then we can compare with a basic setup.

problem with using "a 2 plate cell as a dummy load" is that i have very little experience with electrolysis other then what we did with Mike's SMD.
But from that i know that the cell is very hard to measure for resistance (ideal 50 Ohm, but we could adjust the output filter).
Also it has a big capacitance value, which need to be known and compensated for.

So is there a simple way to sample the cell for resistance/capacitance?

But making DC out of RF is not what we want/need, its the chaos caused by the RF - harmonics - hetrodyning that should do the breaking of the molecular bonds we are after, see Mike's PDF in his post #119.

These are the problems we need to solve, keep on coming with those suggestions / solutions.

By the way, here the diagram of the amplifier used in my above mentioned video:
(it comes from this link:   http://users.skynet.be/BillsPage/ClassE.html  )

Regards Itsu

Quote from: Itsu on 2015.06.15, 09:17:51
Thanks Tinman,

Sounds logical to have a reference yes, then we can compare with a basic setup.

problem with using "a 2 plate cell as a dummy load" is that i have very little experience with electrolysis other then what we did with Mike's SMD.
But from that i know that the cell is very hard to measure for resistance (ideal 50 Ohm, but we could adjust the output filter).
Also it has a great capacitance value, which need to be known and compensated for.

So is there a simple way to sample the cell for resistance/capacitance?

But making DC out of RF is not what we want/need, its the chaos caused by the RF - harmonics - hetrodyning that should do the breaking of the molecular bonds we are after, see Mike's PDF in his post #119.

These are the problems we need to solve, keep on coming with those suggestions / solutions.

Regards Itsu

Well if you just want to use the two plate cell as a resistive load,then leave it AC.
To work out resistance of the cell,just use ohms law(as you do indeed have capacitance).
So just use a known AC voltage across the cell,and see how much AC current is being drawn,and from there you can work out your resistance. From there you just keep adding your Elite until you reach the resistance value you want. Now,it will be out a little due to the capacitance,but at those frequencies the capacitance value wont be that high,so your resistance value will be close.
Hope that helps.
Here is a link to a page on liquid resistors. This should get you through.
http://www.nessengr.com/techdata/liqresistor/liquidresistor.html

Hi TinMan

I don't think we can compare any output to Faraday electrolysis, that is not what we want. I think first is to get it working, that is to produce a gas or gas mixture as in the Kanzius setup "no electrodes or direct contact with the water". Once we have that then we can look at the calorific value of the gas produced, this will have to be measured as there is no real existing make up of the gas, this is all going to be new to all of us, but we are trying to make it simple, well as simple as it can be, and above all safe.

There is a common denominator in all the RF splitting of water to date, chaos, through reducing the carrier and expanding the two side bands of a dual side band signal, we can produce huge power in the modulation frequencies and their chaos from harmonics and heterodyne generated frequencies, " it is not the carrier but the modulator", this is where most have missed the point. The carrier could be just about any frequency, it is just that, a carrier, or better understood by my term, the Trojan horse.

The modulation frequencies can be anywhere from DC to 200KHZ or more, and not just one but many.

regards

Mike 8)

Storm here so shutting down.

Quote from: Centraflow on 2015.06.15, 13:53:20
Hi TinMan

I don't think we can compare any output to Faraday electrolysis, that is not what we want.

Hi Mike,

I would be interested in comparing RF phase change to Faraday electrolysis in terms of gas pressure produced per unit of energy used.

Thanks, good thread!  O0

Quote from: Chet K on 2015.06.14, 15:53:46
Gentlemen  

Here we will be exploring the breaking of molecular bonds in "water" through vibrational reaction".

Various members of this forum have been working aside on this idea, in reality it is not new, it all started back in the 1930's with Dr. Royal Rife, then in the 1970's Dr. Andrija Puharich, and more recently Kanzius with his burning of salt water. What do they all have in common?

They were all working to find a cure for cancer by manipulating the structure of the cancer cells and were using the basic recipe from the start of RF in a type of chaos to vibrate the molecules within those cells.

Rife was relatively low power and so was Puharich to start with until he found out what was happening, his higher power system was never published but he did patent the basics which showed the efficiency of using a type of modulated RF.

As a side note, Dr. Royal Rife's approach was from resonance standpoint (http://www.bibliotecapleyades.net/ciencia/ciencia_vibrationalmedicine.htm) and this is much more effective way to reach result than using brutal force.
Also using filters in circuit is limiting ability to adopt resonant frequency when it is shifting...

Cheers!

Quote from: T-1000 on 2015.06.15, 22:51:26
As a side note, Dr. Royal Rife's approach was from resonance standpoint (http://www.bibliotecapleyades.net/ciencia/ciencia_vibrationalmedicine.htm) and this is much more effective way to reach result than using brutal force.
Also using filters in circuit is limiting ability to adopt resonant frequency when it is shifting...

Cheers!

What we are trying to do is vibrate the molecules through resonance of those molecules as has been explained. To try and hit the right frequencies and maintain the resonance as needed is very very difficult, so the idea is to hit them with chaos so as to guarantee the resonance.

As far as filtering, this is normally the carrier, here we don't really want the carrier, the work will be done by the modulating frequencies and their harmonics etc, which will not be affected by the filter, we hope, if they are we will remove the filter and use a very wide band transformer, this is all experimentation O0 but the idea is sound.

We need input form people for the delivery of the RF, coil/antenna. I am looking at Petlowany pancake coil antennas and also Helmholtz coils at the moment. The delivery  of the RF is probably the most important part, wide band double side band with diminished carrier is not a real problem, the chaos we can create but delivery is another thing.

regards

Mike 8)

TinMan Had mentioned this Link.

http://www.rexresearch.com/kanzius/kanzius.htm

A Lot of info there.

I made a new output module, with values tuned for 13.56mHz.

It has similar performance as the other one running on 4.5mHz, allthough i need to redo one of the coils as it turned out to be peaking to low (11.5mHz) in frequency.

Input drain voltage was 41.4V, driver on 12V

Screenshot shows:
yellow: input signal from FG
blue:   output signal across the 55 Ohm dummy load  (262V  = ~150W)

The diagram is the circuit used for 13.56mHz (only the output part!!!)


So we can easily swap out the output module to change the frequency we want to work on.

https://www.youtube.com/watch?v=RzUSfxi2Auk&feature=youtu.be  

Regards Itsu

150 Watts? How long can you run it before your load resistors start smoking? Have you melted the plastic of the springclip on your scope probe yet?

Nice Itsu

I was thinking about exactly what you have done along with Grum, moving up to 13.56MHz, we can keep it in the scientific legal area.

@TK

Only 2sec and it will smoke the resistors, long enough to get the scope shot to calculate the power output though, at 100v + DV it is going to be around 500w RF.

I was thinking at these frequencies it is going to be near field and so mainly a magnetic field used as opposed to an electric field, so we might try a Helmholtz coil setup, will have to find the right size etc for the frequency and impedance tomorrow.

regards

Mike 8)

PS your right the patent sizes etc just do not work out right, the patent is totally stupid, who ever did it.

Quote from: Centraflow on 2015.06.15, 13:53:20
Hi TinMan

I don't think we can compare any output to Faraday electrolysis, that is not what we want. I think first is to get it working, that is to produce a gas or gas mixture as in the Kanzius setup "no electrodes or direct contact with the water". Once we have that then we can look at the calorific value of the gas produced


regards

Mike 8)

Storm here so shutting down.

I was just thinking that it would be good to know how much power is actually needed to achieve the flame seen in the Kanzius video using standard electrolysis. I would guess that around 1.5 to 2 LPM of hydrogen is all that the Kanzius setup was producing to obtain that flame rate. I will still modify my cell to separate the H and O ,and see how we go.
It's good to have a base line power to see where we need to get to. O0

Now that's something I would like to see, for Itsu to see the flame effect (for his personal astounding efforts anyway) and then to know of the power requirements.
The setup is looking a bit out of my own league, anything like 150W and > 12V is such a case. But, if that's what it takes then that's what it takes. I'm concerned that we do have a wooden house  >:-)
"Hey honey come and look, it works....and call the fire brigade"

All said, if it's a resonance method, then from there could be room to bring input power down.
Is it a chain reaction effect ? a focused beam/split effect ? such things aren't known yet.

Quote from: Centraflow on 2015.06.16, 08:44:53
We need input form people for the delivery of the RF, coil/antenna. I am looking at Petlowany pancake coil antennas and also Helmholtz coils at the moment. The delivery  of the RF is probably the most important part, wide band double side band with diminished carrier is not a real problem, the chaos we can create but delivery is another thing.

Note, that the Kanzius patent mentions parts of the TX antenna operating at >20kV electric potentials.
Similarly, TeslaCoil transmitters / resonators operate at deliberately high VSWR in order to obtain high potentials, too.
Also, the TX & RX heads, described in the patent, separated by an air gap, form more of an HV air capacitor than a high current inductor.

High current Helmholtz coils are useful for generating strong homogeneous magnetic fields.  Such fields are customarily needed to minimize spin decoherence in NMR.
Whether this is useful depends on spin axis precession coherence being a part of the MO.

As a reminder: Capacitors are voltage devices while inductors are current devices. HV in an inductor does nothing for its magnetic field.

Hi Verpies

Quote from: verpies on 2015.06.17, 05:40:48
Note, that the Kanzius patent mentions parts of the TX antenna operating at >20kV electric potentials.
Similarly, TeslaCoil transmitters / resonators operate at deliberately high VSWR in order to obtain high potentials, too.

I think if it was running at a high VSWR something would have given at these powers, I don't think an ATU would help much (especially automatic as in the YEASU) there are many things that just do not square up in the patent application, the spec of the antenna for one.

Also, the TX & RX heads, described in the patent, separated by an air gap, form more of an HV air capacitor than a high current inductor.

Yes I thought of that, then discounted because it is a near field antenna at these frequencies, so magnetic field.

High current Helmholtz coils are useful for generating strong homogeneous magnetic fields.  Such fields are customarily needed to minimize spin decoherence in NMR.
Whether this is useful depends on spin axis precession coherence being a part of the MO.

I don't think coherence comes into this, I think it is pure molecular resonance in all parts of the substance within the field (H2O+Nacl) causing a shearing of their bonds.

As a reminder: Capacitors are voltage devices while inductors are current devices. HV in an inductor does nothing for its magnetic field.

Very true, so what do we have here, bearing in mind this is a high wattage transmitting" coil" operating in the near field.

This is why we need the likes of yourself ;) to help us find what is really going on and why

Best regards

Mike 8)

Quote from: Centraflow on 2015.06.17, 07:24:28
Very true, so what do we have here, bearing in mind this is a high wattage transmitting" coil" operating in the near field.

Near field EM radiation looks like these inner loops in the video below:

  Intriguing thread!  i'm back from extensive travels to visit children and grand-kids and other family; so hope to catch up a bit.

TinMan wrote intriguingly:

QuoteI already spent time and money on an accurate measuring device when I was interested in Les' s thread

Can you tell us about this device?

I'm looking for a "power analyzer" that can handle output at higher voltages and frequencies - especially at higher frequencies like one might get from a blocking oscillator.  With such devices, measuring input power (usually DC) is quite easy, but measuring output power can be very difficult.  I've tried rectifying and dumping the energy onto a capacitor; I've tried dumping the power into a resistor and using calorimetry -- but these "measuring" efforts CHANGE the circuit whose output power i'm trying measure!  Yes, i've used a fast scope and V(t)*I(t) - and take an average power from the waveform...  concerns there with offsets and sampling rate etc... 
Surely there's something out there...

Quote from: PhysicsProf on 2015.06.17, 15:20:31
   I'm looking for a "power analyzer" that can handle output at higher voltages and frequencies - especially at higher frequencies like one might get from a blocking oscillator.  With such devices, measuring input power (usually DC) is quite easy, but measuring output power can be very difficult.  I've tried rectifying and dumping the energy onto a capacitor; I've tried dumping the power into a resistor and using calorimetry -- but these "measuring" efforts CHANGE the circuit whose output power i'm trying measure!  Yes, i've used a fast scope and V(t)*I(t) - and take an average power from the waveform...  concerns there with offsets and sampling rate etc... 
Surely there's something out there...

There is a type of photometric power meter which consists of two identical cavities abutting each other each containing identical filamentary light bulbs.  The light bulbs back-illuminate abutting ground-glass screens so that light intensity can be compared. One bulb is fed with RF power from the source to be measured while the other bulb is fed with DC.  By adjusting the DC to get equal illumination you can then accurately measure the DC power which should equate to the unknown RF power.

Smudge

Or alternatively.....

Attached is Verpies's watt meter design. This has been presented many times before, with, I may add, no interest !!

I feel this would be a suitable candidate for funding !!   ;)

Cheers Grum.

Grum,

Very nice simple and compact circuit, I don't recall seeing it before this. It should fit on a small chip carrier board and be inexpensive, all good qualities.

A digital display should be able to be added pretty easily as well. Thank you for posting it again and thank you Verpies.

Quote from: Grumage on 2015.06.17, 19:02:26
Or alternatively.....

Attached is Verpies's watt meter design. This has been presented many times before, with, I may add, no interest !!

I feel this would be a suitable candidate for funding !!   ;)

Cheers Grum.

Good Day Grun & All,

Yes, nice idea......
Are we talking SMD, FR-4, two-layer pcb, ground plane, with interface for PIC/Arduino LCD display?
Maybe use an ATTiny85 for the A/D conversion, real small, not a lot of board real estate.
Arduino/LCD display could run off of the *same* 7805 linear.
Any special shielding needed?
What type of input/output connectors (for the AC power signal) are we talking about?
I regularly design pcbs on DipTrace software, could probably setup the design on about 8 cm*2 board area with SMT.
Anyway, count me in as it looks like a useful tool.

take care, peace
lost_bro

Quote from: Grumage on 2015.06.17, 19:02:26
Attached is Verpies's watt meter design. This has been presented many times before, with, I may add, no interest !!

Actually, Itsu took a good crack at it, but unbeknownst to me he bought the 2GHz unbuffered version of the multiplier chip with low input impedances, while I was working with the 1GHz buffered version with the "B" suffix with high input impedances (a sample from AD).

For this schematic to work with the unbuffered version of the multiplier chip, some of the resistors need to be altered to match its low input impedances.

Quote from: verpies on 2015.06.17, 23:04:23
Actually, Itsu took a good crack at it, but unbeknownst to me he bought the 2GHz unbuffered version of the multiplier chip with low input impedances, while I was working with the 1GHz buffered version with the "B" suffix with high input impedances (a sample from AD).

For this schematic to work with the unbuffered version of the multiplier chip, some of the resistors need to be altered to match its low input impedances.

Verpies,

Do you have time to redesign your circuit for the 2GHz un-buffered version of the ADL5391 IC?

I did make a Eagle CAD lib for the ADL5391 and I think it will be very difficult to hand solder the IC.
Attached is the footprint of the IC compared to a 0805 capacitor. IC is 3X3 mm in size.

GL.

Quote from: Groundloop on 2015.06.18, 06:45:27
Do you have time to redesign your circuit for the 2GHz un-buffered version of the ADL5391 IC?

No, but I have diapers and CMV ;)
Nonetheless, this needs to be done and time can always be scrounged up.
First, I'd have to buy the unbuffered chip to verify that my alterations work as intended.

Quote from: Groundloop on 2015.06.18, 06:45:27
I did make a Eagle CAD lib for the ADL5391 and I think it will be very difficult to hand solder the IC.

Yes, it is difficult but I had done it and so did Itsu - I was surprised when he did because people his age usually have problems with eyesight and fine motor control ...but apparently that did not apply to him.  
Our Russians friends probably would  need some vodka, because without it, the handshaking would prevent any success with soldering this puny chip.
Anyway, for low frequency experimenting, I prefer to solder this chip to a DIP8 socket and go from there...

Quote from: verpies on 2015.06.18, 08:03:39
No, but I have diapers and CMV ;)
Nonetheless, this needs to be done and time can always be scrounged up.
First, I'd have to buy the unbuffered chip to verify that my alterations work as intended.
Yes, it is difficult but I had done it and so did Itsu - I was surprised when he did because people his age usually have problems with eyesight and fine motor control ...but apparently that did not apply to him.  
Our Russians friends probably would  need some vodka, because without it, the handshaking would prevent any success with soldering this puny chip.
Anyway, for low frequency experimenting, I prefer to solder this chip to a DIP8 socket and go from there...

verpies,

I have started to design a board around the PIC16F88 mcu. I plan to use RS232 to send data to a PC.
I will implement two digital variable resistors so that the offset and gain can be controlled by firm ware.
The built in A/D in the PIC is 11 bit so I plan to use an external A/D of 12 or more bits.

Thanks for taking time to look into this.

GL.

I had to dig it out of my projects box.

First picture; the layout of the circuit how i set it up
Second picture; zoomed in on the puny chip
Third picture; on my age you need something like that.

It never worked like planned, probably because of the wrong (2GHz unbuffered) chip.


I think it still looks very promising, so please go for it.


Regards itsu

Quote from: Itsu on 2015.06.18, 08:53:05
I had to dig it out of my projects box.

First picture; the layout of the circuit how i set it up
Second picture; zoomed in on the puny chip
Third picture; on my age you need something like that.

It never worked like planned, probably because of the wrong (2GHz unbuffered) chip.


I think it still looks very promising, so please go for it.


Regards itsu

Itsu,

Thank you for posting your build. I plan to make 2 PCBs, one is the circuit and a small PCB for the IC that give me
a standard 16 pin DIL. That way I can get someone that are able to solder the small IC onto the DIL board. The
rest of the board uses standard easy to solder through hole components. I plan to make the PCB fit a Hammond
standard alu. box. (Hammond 1455C801BK). The circuit will have USB to get data into a PC. The USB will power
the circuit.

EDIT: Has started a project over here: http://www.overunityresearch.com/index.php?topic=3106.msg49663;topicseen#msg49663

GL.

Quote from: Groundloop on 2015.06.18, 11:12:49
EDIT: Has started a project over here: http://www.overunityresearch.com/index.php?topic=3106.msg49663;topicseen#msg49663

Shit!  Now I will definitely have to scrounge up some time for it.

there are solutions for that,   you will be having your hands free and the kid will be learning something   ;D

Regards Itsu

Quote from: Itsu on 2015.06.18, 20:36:02
there are solutions for that,   you will be having your hands free and the kid will be learning something   ;D

Regards Itsu

;D ;D ;D ;D ;D ;D ;D ;D........................... ;)

Ones a doddle, been there, " T shirt " etc. etc.

O0

Meanwhile i was running some tests on my 13.56mHz amplifier module, but allthough 150W was reachable, the efficiency stayed very low <40%.
Also the current through the driver ixdd414ci went up from 500mA at 4.5MHz to 1.8A at 13.56MHz which is out of its spec's.

I think its the driver ixdd4141ci which cannot handle this high frequency, so therefor i tested it without voltage on the drains.

Yellow is the voltage on the output of the driver / gates
blue is the input from the FG.

First screenshot is at 4.5MHz, second on 13.56MHz.

You can see that the output of the driver drops in amplitude, the signal gets distorted (more sawtooth like) and shifts in phase.
The MOSFET's will have a hard time to switch on/off hard this way causing the bad efficiency i think.

I did add an IDH12SG60C schottky diode across both drain/sources of the MOSFET's to aid the body diodes, but without improvements.

Any thoughts on this, can i improve on the gate signal in any way?
Or should i find a better driver like a DEIC420?

Regards Itsu

Hi Itsu

have to go out and will look more later, but maybe it is the capacitance of the gate (being Two) in relation to the increase of frequency, what happens if you disconnect one? and power up slowly to voltage

back later

regards

Mike 8)

Quote from: Itsu on 2015.06.18, 20:50:43
First screenshot is at 4.5MHz, second on 13.56MHz.

With 0V between drain and source ?

Quote from: Itsu on 2015.06.18, 20:50:43
You can see that the output of the driver drops in amplitude, the signal gets distorted (more sawtooth like) and shifts in phase.

Sawtooth waveform means that the driver is too slow and you are approaching its slew rate limit.  It does not mean that the driver is too weak (max source/sink current).
What is the driver's minimum rise time, anyway?  
Are you seeing this driver's maximum slew rate (V/ns) on the scope when there is 0V between drain and source  - as not to be bothered by the Miller effect ?

From the datasheet:   

"The IXDD414 can source and sink 14A of peak current while producing voltage rise and fall times of less than 30n".

Yes.


Itsu

Quote from: Centraflow on 2015.06.19, 07:59:49
Hi Itsu

have to go out and will look more later, but maybe it is the capacitance of the gate (being Two) in relation to the increase of frequency, what happens if you disconnect one? and power up slowly to voltage

back later

regards

Mike 8)

To answer Mikes question, the FQA11N90C MOSFET has an Ciss (input capactitance) of 2530pF typical.
So for 2 MOSFET's that means 5nF.

In the driver datasheet is a section mentioning:

"Say, for example, we are using the IXDD414 to charge a 5000pF capacitive load from 0 to 25 volts in 25ns.
Using the formula: I= ∆V C /∆t, where ∆ V=25V C=5000pF & ∆ t=25ns we can determine that to charge 5000pF to 25 volts
in 25ns will take a constant current of 5A.  
(In reality, the charging current won't be constant, and will peak somewhere around 8A)"


So that means to me that this driver should be able to drive a 5nF capacitive load (the driver is fed from a 12V battery).

Regards Itsu

Quote from: Itsu on 2015.06.19, 11:18:01
From the datasheet:  
"The IXDD414 can source and sink 14A of peak current while producing voltage rise and fall times of less than 30ns".

Well, then connect just a 5Ω non-inductive resistor to the output of this driver and verify that its output can really rise in 30ns - there are a lot of counterfeit chips out there nowadays with inferior characteristics.

14A means a strong driver but 30ns is not very quick

Even if the output of this driver can rise in 30ns, it probably still needs another 30ns to fall.  So the best you can do with this chip is a triangular waveform (or asymmetrical  sawtooth) with a minimum period of 60ns.
...and 60ns is the period of 16.6MHz triangular waveform.  That's pretty close to your 13.6MHz

OK,  good plan, i just have to find myself a 5Ω non-inductive resistor.

But if it confirms the triangle waveform, then i really need a faster driver.


Thanks,     Itsu

Quote from: Itsu on 2015.06.19, 11:50:39
OK,  good plan, i just have to find myself a 5Ω non-inductive resistor.
But if it confirms the triangle waveform, then i really need a faster driver.

You can always connect several carbon resistors in parallel.

Remember that the 5Ω resitor to ground is only a sourcing load for the driver, so the rise time will be much slower than the fall time, which is not opposed by any loading resistor to V_CC.

If you still have some of the UCC27511 drivers then note that they are fast (7ns) but to be able to meet the 14A sink current specification of IXYS you'd need to parallel 2 of them.

Ok,  4x 22 Ohm parallel (5.5 Ohm) from driver output to ground.

First screenshot overall signal at 13.5MHz, looking good:
yellow: input from FG
Blue:   output from driver to ground

Next 2 screenshots are zoomed in on the rise / fall times of 4.5MHz, then 13.5MHz (look at the increased delay on 13.5MHz)
Also looking good,  the 4x 22 Ohm resistors getting hot fast.


Regards Itsu

Careful Itsu, they will get hot as the output is around 4w or more depending on voltage input.

Looks like the driver is fine, very clean, I think the problem is the mosfets or maybe (the 0.5 ohm 5w resistor if left out) @ 13.56MHZ.

Other problem could be a very bad match on the output @ 13.65MHz.

Most of these mosfets are good up to 30MHz it seems, so something around the mosfets is causing this, "SWR", check this with the swr meter you have at a lower power output (reduce the drain voltage).

Part of your dummy load could be shot with the power being put into it before!!

Not much left in the circuit to think about :-\

Regads

Mike 8)

Oops,  looks like i measured on 4.5 and 13.5 KHz  instead of MHz,    need to redo those tests.......

You posted the alteration during my post :)

OK

standing by

Mike 8)

Mike,  yes,  sorry about that, i found those screenshots very clean, too clean.
Anyway,  now ones are up now, but i think looks ok still.

Guess you are right,  probably a bad mismatch in the output which reflects back on the input (driver).  
By the way, i have 2x 0.1 Ohm resistors in the gate lines one for each MOSFET

Itsu

Next test with only 1 MOSFET attached,  no drain voltage applied.

Again yellow input FG, blue gate signal.  first on 4.5MHz,  then on 13.5MHz.
So we see a dramatic difference compared with the signals of only the 5.5 Ohm resistor attached.

Regards Itsu

Quote from: Itsu on 2015.06.19, 14:06:00
Mike,  yes,  sorry about that, i found those screenshots very clean, too clean.
Anyway,  now ones are up now, but i think looks ok still.

Guess you are right,  probably a bad mismatch in the output which reflects back on the input (driver).  
By the way, i have 2x 0.1 Ohm resistors in the gate lines one for each MOSFET

Itsu

OK on the resistors, better safe than sorry. Try checking the SWR with lower power which your meter can take, make up a 10w 50 ohm load if you can O0

regards

Mike 8)

Quote from: Itsu on 2015.06.19, 14:19:04
Next test with only 1 MOSFET attached,  no drain voltage applied.

Again yellow input FG, blue gate signal.  first on 4.5MHz,  then on 13.5MHz.
So we see a dramatic difference compared with the signals of only the 5.5 Ohm resistor attached.

Regards Itsu

Looks like mosfet problem at 13.56MHz

Do you have another mosfet? if so try one

regards

Mike 8)

This is same test as above, but now with 2 MOSFETs attached,  no drain voltage applied  (no output module attched either).

4.5MHz stays ok,  13.5MHz gets even worse:

So it looks to me that the driver should be ok on 13.5MHz,  but somehow the MOSFETs (capacitance?) cause the driver to misbehave.

Regards Itsu

Dear Itsu.

Am I being daft?
Your second screen shot reads over 60 MHz!! Well that's what your scope says.

Cheers Grum.

I think the mosfet is no good for the higher 3X frequency or they are damaged from before, though the 4.5 signal seems OK, so, can't take the higher frequency without breaking down internally it seems.

regards

Mike 8)

Hi Grum,

nicely spotted,  i did not see that.

Guess its because of the extra peaks on that signal, so the scope gets confused.

Regards   Itsu

Quote from: Itsu on 2015.06.19, 12:50:48
OK,  4x 22 Ohm parallel (5.5 Ohm) from driver output to ground.

First screenshot overall signal at 13.5MHz, looking good:
yellow: input from FG
Blue:   output from driver to ground

Next 2 screenshots are zoomed in on the rise / fall times of 4.5MHz, then 13.5MHz (look at the increased delay on 13.5MHz)
Also looking good,  the 4x 22 Ohm resistors getting hot fast.

Looks like the IXIS driver can rise in 7ns with almost 3A flowing through it (I assume 15V V_CC).  That is pretty quick.
The phase shift is caused by the driver's propagation delay (30ns) but this delay is not the same as the rise time.

To further characterize this driver's performance under heavy load you can use one 1/4W 1.5Ω carbon resistor to stress the driver even more, but to prevent this resistor from burning up you should use very sparse pulses (low duty cycle).

If you had your versatile Rigol generator, you'd set it up like this:

1) Set CH1 of your signal generator to the Square waveform (Period: 100ns, StartPhase: 0º, Duty Cycle: 50%)
2) Set the Burst mode of CH1 to (Type: N_Cycle, Cycles: 1, Burst Period: 20ms., StartPhase: 359.999º, Source: Internal, Delay: 0 ).

This will set your signal generator to output a 100ns positive pulse every 20 milliseconds (very low duty cycle) that will not burn up the resistor even if there is more than 10A flowing through it.

If you want to test the fall time under load (sinking performance) jest connect the load resistor to V_CC.

Of course MOSFETs present capacitive loads to the driver, which is a little different because at the beginning of the pulse capacitors behave like a 0Ω resistor (short) and after 5 RC constants they behave almost like infinite resistance (open).

This is further complicated by the Miller effect, but we won't go there for the driver performance characterization alone.
One remedy for the Miller effect is cascode configuration.

Quote from: Itsu on 2015.06.19, 14:19:04
Next test with only 1 MOSFET attached,  no drain voltage applied.
Again yellow input FG, blue gate signal  <snip>  on 13.5MHz.
So we see a dramatic difference compared with the signals of only the 5.5 Ohm resistor attached.

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=18866)

Yes, that is a difference between resistive load and capacitive load.  It is classic and that is the way it is supposed to look with this RC constant.

The only discrepancy from ideal capacitance charging curve are those squiggles that I marked in red circles.  They could represent reflections or some phenomena inside the MOSFET - I wonder which one.  Do these squiggles remain if you connect the driver's output to a lone pulse capacitor of comparable capacitance, instead to the MOSFET's gate ?

Anyway, to square this signal some more (now you have a distorted triangle waveform) you'd need to hit this gate capacitance with higher voltage and current.  
This is difficult and risks gate oxide puncturing if you allow the voltage across this capacitance to exceed 20V, but you can get away with charging it with a higher voltage without damage if you stop charging before the voltage across this capacitance exceeds 20V.  This is advanced stuff.

Quote from: Itsu on 2015.06.19, 14:34:18
but somehow the MOSFETs (capacitance?) cause the driver to misbehave.

Yes, it looks like the driver cannot handle that much gate capacitance and the resulting spikes case your oscilloscope to misread the pulse frequency.

I don't know how expensive these IXIS drivers are, but I suggest using one driver per one MOSFET instead of one driver per two MOSFETs. 
If you feel very adventurous, you could try two paralleled drivers per one MOSFET.

Thanks verpies,

great analysis once again.
That capacitor test looks a good one to do.
Increasing the drivers Vcc to 24V is possible, however at 1.8A it will exceed its power level specs by over 100%
Using 1 driver / MOSFET is possible, they are not that expensive and i still have a spare one.

Here 2 short video's, first one shows how i did the last tests,
the second one showing that on 4.5MHz all is still working very fine (200W output on the Bird Wattmeter).

https://www.youtube.com/watch?v=n5kpIdr4cWk&feature=youtu.be

https://www.youtube.com/watch?v=K-DrchtPjPI&feature=youtu.be

Regards Itsu

2.9nF (3x MKP caps parallel) on the output of the driver alone, first screenshot at 4.5MHz, second on 13.5MHz:


Itsu

Quote from: Itsu on 2015.06.19, 17:07:41
Thanks verpies,

great analysis once again.
That capacitor test looks a good one to do.
Increasing the drivers Vcc to 24V is possible, however at 1.8A it will exceed its power level specs by over 100%
Using 1 driver / MOSFET is possible, they are not that expensive and i still have a spare one.

Here 2 short video's, first one shows how i did the last tests,
the second one showing that on 4.5MHz all is still working very fine (200W output on the Bird Wattmeter).

https://www.youtube.com/watch?v=n5kpIdr4cWk&feature=youtu.be

https://www.youtube.com/watch?v=K-DrchtPjPI&feature=youtu.be

Regards Itsu

Wow, like your Bird watt meter $$$$$ :D

Yes I would say those mosfets don't like the higher frequency for some reason.

200w @ 42v is very good. Normally if you double the voltage you will quadruple the output (800w) :D

I would work with the 4.52Mhz as the third harmonic down, not sure it is not also industrial like 13.56 X 2 = 27.12MHz  13.56/3 = 4.52MHz. shared with the Ham bands as some are ;)

Verpies also from me , great analysis, I was thinking of something about the capacitance of the fets at that frequency for some reason, changing to a different brand (IRF's  or the like) might be interesting if there are some knocking around.

regards

Mike 8)

I'm wrong it is 6.78MHz, the other is correct

regards

Mike 8)

Quote from: Itsu on 2015.06.19, 17:31:39
2.9nF (3x MKP caps parallel) on the output of the driver alone, first screenshot at 4.5MHz, second on 13.5MHz:

Nooooo!  Why is the output more distorted at lower frequency than the higher ????

Could it be that longer switching period gives the chance for a 14MHz LC ringing to occur?  
How long are the wires between the driver and the 2.9nF cap ? ...and the loop area of these wires?

Quote from: Centraflow on 2015.06.19, 17:53:01
Wow, like your Bird watt meter $$$$$ :D

Yes I would say those mosfets don't like the higher frequency for some reason.

200w @ 42v is very good. Normally if you double the voltage you will quadruple the output (800w) :D

I would work with the 4.52Mhz as the third harmonic down, not sure it is not also industrial like 13.56 X 2 = 27.12MHz  13.56/3 = 4.52MHz. shared with the Ham bands as some are ;)

Verpies also from me , great analysis, I was thinking of something about the capacitance of the fets at that frequency for some reason, changing to a different brand (IRF's  or the like) might be interesting if there are some knocking around.

regards

Mike 8)

Mike,   i always wanted to own a Bird 43 Wattmeter, and just ran into this bargain, could not resist.

I tried 82V on the drains, not really  quadrupling the output, but more then 500W on 4.5Mhz, see picture.
The dummyload went up in flames right away, so could not tune  :(

I have 2   DE275X2-102N06A coming, also a bargain on Ebay, so could try them in parallel mode.


Regards Itsu

Quote from: verpies on 2015.06.19, 18:49:21
Nooooo!  Why is the output more distorted at lower frequency than the higher ????

Could it be that longer switching period gives the chance for a 2.5MHz LC ringing to occur?  
How long are the wires between the driver and the 2.9nF cap ? ...and the loop area of these wires?

Yes,  good question.

I had 1 cm length of wires running from the caps and another 2cm of distance from ground point to ground driver making a 4cm loop, shorter is hardly possible.
I could reduce the grounding point distance somewhat.

Itsu

QuoteTo further characterize this driver's performance under heavy load you can use one 1/4W 1.5Ω carbon resistor to stress the driver even more, but to prevent this resistor from burning up you should use very sparse pulses (low duty cycle).

If you had your versatile Rigol generator, you'd set it up like this:

1) Set CH1 of your signal generator to the Square waveform (Period: 100ns, StartPhase: 0º, Duty Cycle: 50%)
2) Set the Burst mode of CH1 to (Type: N_Cycle, Cycles: 1, Burst Period: 20ms., StartPhase: 359.999º, Source: Internal, Delay: 0 ).

This will set your signal generator to output a 100ns positive pulse every 20 milliseconds (very low duty cycle) that will not burn up the resistor even if there is more than 10A flowing through it.

Ok,  tried that,  but the result was not what i would expected see first screenshot.

So i tried without the burst mode setting, see second screenshot.

Regards Itsu

I tried the cap test again, now with a single 2.2nF ceramic capacitor almost directly soldered on the output / ground lead of the driver (0.5cm leads)
Result is the same:

Regards Itsu

Quote from: Itsu on 2015.06.19, 19:32:48
Ok,  tried that,  but the result was not what i would expected see first screenshot.

So I immediately can see that I made an arithmetic mistake and forgot about the 50% duty cycle setting.  I should have written:
"This will set your signal generator to output a 50ns positive pulse every 20 milliseconds"

Nonetheless, the scopeshot shows that the driver has no problems sourcing currents close to the 8A mark (assuming 12V V_CC)

Quote from: Itsu on 2015.06.19, 19:32:48
So i tried without the burst mode setting, see second screenshot.

...and your 1.5Ω 1.4W resistor did not vaporize ?!

Quote from: Itsu on 2015.06.19, 19:46:14
I tried the cap test again, now with a single 2.2nF ceramic capacitor almost directly soldered on the output / ground lead of the driver (0.5cm leads)
Result is the same:

I don't think so.  If you look at the LC ringing frequency then it was approximately ~14MHz before and now it is >28MHz (35ns period)
Over 200% change is a significant one and supports the thesis that the capacitor loop is ringing because you decreased this loop and the ringing frequency increased significantly (more than can be explained by the -24% decrease in capacitance which is under a radical in LC frequency formula).

Zoom and check my scoposcopy in case I made a mistake.

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=18884)

Quote...and your 1.5Ω 1.4W resistor did not vaporize ?!

No,  but in 1 second it had no change i guess.

QuoteZoom and check my scoposcopy in case I made a mistake.

Right,  i see,   i was able to measure the last ringing, the first one is much lower in frequency, so indeed the cap is ringing on the lower frequency.

Itsu

Quote from: Itsu on 2015.06.19, 20:26:19
No,  but in 1 second it had no change i guess.

Amazing!  
Average Power = DutyCycle * V² / R
50% * 12V² / 1.5Ω = 48W
...pretty good for a 1/4W resistor even for 1s.

Maybe some overload protection kicked in inside the driver and the current became limited.

Probably, it does come with an "enable" pin to be used for shutting off the output, however i have hard wired this pin to Vcc  :o

Itsu

So somehow either the driver (IXDD414ci) or the MOSFETs (FQA11N90c) or the combination is not suitable for 13.56MHz.
Research via Google confirms no designs to be available for 13.56MHz with those components, so not sure why i thought it would work.
I have an IXRFD630 driver and DE275X2-102N06A MOSFET on order which should be able to handle 13.56MHz for lateron tests   


I will use for now the 4.5MHz module i have also because my FG will be away for repairs, so will be using my Chinese FG (till 5MHz)

Things to do:

# further RF sealing the amplifier and (new) dummy load
# build a (regulated) 100V / 5A PS
# looking into the modulation part (audio amp. modulating the drain voltage)
# how to deliver the RF to the target (via antenna's / air capacitors. ??)

Thanks all for your help up till now, please continue to contribute / replicate whenever you can.


Regards Itsu

Itsu

where haver you ordered your parts from in Europe? that dual mosfet will handle over a Kw :D but can't find a supplier

regards

Mike 8)

Hi Mike,


i use this website to find parts:   http://www.findchips.com/

Not specific Europe, but Farnell and Digi-key operate also in Europe and deliver very fast.
I would order the  IXRFD630  driver from digi-key.

Regards Itsu

Quote from: Itsu on 2015.06.20, 17:09:10
Hi Mike,


i use this website to find parts:   http://www.findchips.com/

Not specific Europe, but Farnell and Digi-key operate also in Europe and deliver very fast.
I would order the  IXRFD630  driver from digi-key.

Regards Itsu

yes the driver is no problem, thanks

Mike 8)

Received my  IXRFD630 driver and DE275X2-102N06A MOSFET.
Also my 50 Ohm 100W Globar resistor arrived, so finally can start building the new KW dummy load and the 13.56MHz amp.

The weather is very nice overhere though, so don't expect anything any soon  ;D


Regards itsu

Quote from: Itsu on 2015.06.25, 08:43:32
Received my  IXRFD630 driver and DE275X2-102N06A MOSFET.

Expensive little bugger!  $50

Quote from: verpies on 2015.06.25, 12:16:13
Expensive little bugger!  $50

Yep, but a great performer :D ;D :P

regards

Mike 8)

Looks complicated to get everything connected properly.  Have you guys considered maybe getting one of these evaluation boards to simplify the work a little?

http://www.ixyscolorado.com/index.php/ixys-rf/mosfets-drivers-diodes-power-modules/evaluation-boards

Quote from: Matt Watts on 2015.06.25, 16:10:26
Looks complicated to get everything connected properly.  Have you guys considered maybe getting one of these evaluation boards to simplify the work a little?

http://www.ixyscolorado.com/index.php/ixys-rf/mosfets-drivers-diodes-power-modules/evaluation-boards

That would take the fun out of it ;D

Matt in reality it is not that complicated when you think of what it does. The part that takes a little time is the tuning so as everything flows as it should. That board is a complete frequency generator as well, also it has an output that we may change as and when we have our delivery (antenna) worked out, as we maybe don't have a 50 ohm impedance delivery, all a bit trial and error to start with at very low power so as not to burn up an expensive RF mosfet.

I myself am playing with cheap mosfets to see which will work at the 13.56MHz frequency or half that 6.78MHz which is also a scientific paired frequency with the mili: until I have the delivery sorted out.

regards

mike 8)

Quote from: Centraflow on 2015.06.25, 17:44:52
I myself am playing with cheap mosfets to see which will work at the 13.56MHz frequency or half that 6.78MHz which is also a scientific paired frequency with the mili: until I have the delivery sorted out.

On a side note, I just found out today an IXDD614 and IRFP460 can go to 4.6MHz pretty easy driving a Tesla coil.  Not nearly the power you guys are after, but enough to give me a nasty little RF burn.

Quote from: Matt Watts on 2015.06.26, 08:57:48
On a side note, I just found out today an IXDD614 and IRFP460 can go to 4.6MHz pretty easy driving a Tesla coil.  Not nearly the power you guys are after, but enough to give me a nasty little RF burn.

Yep, up the drain voltage to near the mosfet max and see the power :D

RF Tesla coils are fun and silent unless you modulate with music and they can be a very good HI FI ;)

Carefull with the RF burns, they hurt for a long time.

regards

Mike 8)

Today i completed my 1KW dummy load.

Its a 5 liter can filled with 4 liters of mineral oil, see picture 1

Inside is a 100W induction free 50 ohm Globar resistor, see picture 2

I have a temperature probe in the oil to monitor the oils temperature (180 °C max.)

Hopefully this will lengthen the test time.

Rigol FG is still out for repairs, so no testing possible right now.


Regards itsu

Nice going Itsu

will be interesting to see how it performs O0

regards

Mike 8)

While waiting on the return of my Rigol FG, i was doing some modifications on the amplifier.
I changed the old MOSFET driver IXDD414ci by the new IXRFD360 to see if it can drive the 2 FQA11N90c MOSFETs up till 13.56 MHz.
I also changed the MOSFETs choke by a T200-2 (amidon) toroid with 40 turns giving me 24uH as the old choke (3 turns @ 40uH) got hot.
As my present little FG does not go higher then 5MHz, i could only test with the 4.5MHz module.

It does work as my Bird wattmeter shows 220W @  41.3V/3.9A input (plus another 12W for the driver and 8W from the FG).
But the output signal is not the nice sinewave i expect, so guess i have to wait for my Rigol to return for doing better testing.

Video here:  https://www.youtube.com/watch?v=HIE1ukOm5HM&feature=youtu.be

Output screenshot below.

Regards Itsu

Hi Itsu

Have not looked at video yet but I would say your inductance is too low, should be 40uH min for your choke, this does not only stop RF returning to the supply, but also is part of the tuning circuit. Will look more tomorrow, very hot here 40c and going to bed, but probably not be able to sleep with the unusual heat.

regards

Mike 8)

Mike,

Quotebut I would say your inductance is too low, should be 40uH min for your choke, this does not only stop RF returning to the supply, but also is part of the tuning circuit

is it ?  I wonder, as in the severall E-class amplifier designs for the different frequencies (4.5, 13.56Mhz,  80 and 40 meter bands etc.) i see the same value (40uH).

Also, my present 24uH choke might be somewhat low for the 4.5MHz module (678 Ohm reactance), but at the planned 13.56Mhz it will be 2KOhm.
Found out that my present little FG is putting out rubbish at the 4.5Mhz, so somehow also this FG is toasted  :(
Guess that is the reason for strange output signal, so have to wait for my Rigol FG to return.

Its also unusual hot here (38°C ), so not going to do much as well.


Regards Itsu
 

Quote from: Itsu on 2015.07.02, 08:38:29

Mike,


is it ?  I wonder, as in the severall E-class amplifier designs for the different frequencies (4.5, 13.56Mhz,  80 and 40 meter bands etc.) i see the same value (40uH).

Also, my present 24uH choke might be somewhat low for the 4.5MHz module (678 Ohm reactance), but at the planned 13.56Mhz it will be 2KOhm.
Found out that my present little FG is putting out rubbish at the 4.5Mhz, so somehow also this FG is toasted  :(
Guess that is the reason for strange output signal, so have to wait for my Rigol FG to return.

Its also unusual hot here (38°C ), so not going to do much as well.


Regards Itsu
 

Hi Itsu

that is a strange output, is it the same direct at the output of the SG? in other words an amplified copy?

There seems to be a wide tolerance for the RF choke, that is between 40uH and 200uH, most of the calculators include this in their calculation for the output, that's why I was wondering, especially with that ghosting!

Drink plenty of water in this heat, off to the north of France next week for 10 days with my father in law in the champagne area, long drive for me at my age (64) 12.5hrs from Valencia with stops for food etc.

He has internet so I can look in O0

regards

Mike 8)

Quote from: Centraflow on 2015.07.01, 22:47:00
... for your choke, this does not only stop RF returning to the supply, but also is part of the tuning circuit.

I think so too, because if this choke was only for filtering the power supply and stabilizing the drain voltage then the capacitor would be connected like marked in red color on the schematic below.

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=19036)

P.S.
If the other coils were also wound with Litz wire then the power of this amplifier would be higher because at 13MHz the 50% skin depth in those copper windings is only 12.5µm.
Also, the copper laminate is too close to some of the windings and eddy currents in the laminate must be causing unnecessary losses.

Quote from: verpies on 2015.07.02, 15:56:43
I think so too, because if this choke was only for filtering the power supply and stabilizing the drain voltage then the capacitor would be connected like marked in red color on the schematic below.

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=19034)

P.S.
If the other coils were also wound with Litz wire the the power of this amplifier would be higher because at 13MHz the 50% skin depth in those copper windings is only 12.5µm.
Also, the copper laminate is too close to some of the windings and eddy currents in the laminate must be causing unnecessary losses.

Hi Verpies

Never seen litz wire used at these powers, 1/8"" copper tubing yes, and even 1/4" tubing, we are talking a Kw here at some very high circulating current if the supply voltage is cranked up, and just one mosfet :D

These amps are very efficient, can be 90+%

I have a PDF written by the inventor somewhere, I will post it when I can find it.

regards

Mike 8)

Here it is O0

regards

Mike 8)

Quote from: Centraflow on 2015.07.02, 18:04:38
Here it is O0

Very interesting paper Mike.  Big thanks!

Right off the bat the author mentions never allowing the transistor to see high voltage and high current at the same time, sounds great in concept, but he actually shows how the load network performs this function.  Yet the load does see the amps and voltage at the same time (I think), or if it does, that would be my definition of OU right there.  Being able to split current from voltage and then reassembling it at the point of use.

Good stuff.   O0

Mike,

Quotethat is a strange output, is it the same direct at the output of the SG? in other words an amplified copy?

well, the input is square wave (sort of), but the downward side of the pulse is jittering, and this jittering we see
in the output, but then sine wave like (because of the output tank circuit).

Thanks for the PDF, the Fig. 2 confirms like you and verpies said that the choke is part of the output circuit:



verpies,

Its hard to use litz wire as the output coils are air coils and need stiff copper wire, perhaps when i use some former.
Not sure what you mean by laminate, i guess the copper back side?   If so i can fix that by relocating the toroid.


Thanks,    Itsu

oops Matt, i did not notice your post with the same picture  :)

Anyway, i reinstalled my 3 turn 40uH choke, but the output signal stays similar crappy as with the 24uH choke, so i really think its the FG causing this.

Regards Itsu

Quote from: Centraflow on 2015.07.02, 17:00:02
Never seen litz wire used at these powers, 1/8"" copper tubing yes, and even 1/4" tubing,

It is used in high power designs all the time.  A good source of it is a junked inductive cooker.  They also come in kW ranges
1/4" Copper tubing is good as a low loss rigid coaxial waveguides.

Quote from: Centraflow on 2015.07.02, 17:00:02
we are talking a Kw here at some very high circulating current if the supply voltage is cranked up, ...

Exactly, and a 0.02mm layer of copper cannot support high circulating currents well.

Quote from: Centraflow on 2015.07.02, 17:00:02
These amps are very efficient, can be 90+%

Yes, if they are built efficiently and the coils are tuned exactly to the operating frequency.
Class E amplifiers are tuned narrowband amplifiers - they are not wideband amplifiers !

Quote from: Itsu on 2015.07.02, 18:47:35
Its hard to use litz wire as the output coils are air coils and need stiff copper wire, perhaps when i use some former.

Yes, a thin plastic former compensates for the lack of stiffness

Quote from: Itsu on 2015.07.02, 18:47:35
Not sure what you mean by laminate, i guess the copper back side?  

Yes.  It's enough to put some thick plastic or glass/ceramic spacers between the outside windings and the "copper back side"
Note that on that famous visualization below, there is a magnetic field outside of the solenoid....especially near the windings.

Ok,  the choke is now clear of any copper bottom/back side by 1cm.

QuoteClass E amplifiers are tuned narrowband amplifiers - they are not wideband amplifiers !

I understand we want to modulate the 13.56 Mhz output with an around 40 Khz signal within the output bandwidth of this class-E amplifier.
If this will have no effects, we might need to go for a broadband amplifier approach.

Thanks,  regards Itsu

Quote from: Itsu on 2015.07.02, 20:41:43
I understand we want to modulate the 13.56 Mhz output with an around 40 Khz signal within the output bandwidth of this class-E amplifier.

40kHz frequency deviation is only 0.03% of the 13.56MHz carrier so it fits well into the bandwidth of such narrowband amplifier .

Hi Itsu

Have you taken into account the new mosfet capacitance along with the C1 capacitance, it was just a thought I had just now, just maybe if this mosfet capacitance is higher, then you could remove C1 all together :-\

I'm trying to write up the principles of what we are trying to do here with a bit more explination, such as the carrier frequency does not really react with what we want, it is the modulation frequencies that are of interest at high power (DSB-SC) that is double side band (modulation frequencies) and (SC) suppressed carrier.

We might then get a little more help, I know ION is a ham too, along with being a very good EE :) who else is into radio here? come on own up ;D

regards

Mike 8)

The other thing after looking again at the wave form, it maybe gate phase modulation, in which case it is the SG :-\

regards

mike 8)

Mike,

QuoteHave you taken into account the new mosfet capacitance along with the C1 capacitance

as explained in my post #81 and in the video, i have only changed the new driver.
The MOSFETs are still the 2  FQA11N90C's.
That way i want to look if the problem reaching 13.62MHz is the driver or the MOSFET's.
But as i have no reliable FG, i have to wait.
I did try without the C1 on the 13.56Mhz module, but it did not improve, the problem stayed with the driver (ixdd414ci) pulling to much current on that frequency

I think the MOSFET's will be ok for 13.56MHz, so we won't need the more expensive one.
Another test could be to use 2 drivers (ixdd414ci) one for each MOSFET like mentioned by verpies to see if then 13.56MHz can be reached, but i leave that test for another replicator  :P

Anyway, i am kind of stuck now without a good FG  :(

By the way, are you radio active  ;)  right now, and if so, on what frequencies?

Regards Itsu

The below attached driver chip can be used up to 45 MHz.

Very interesting specifications.

Thanks muDped,    but the DEIC421 is obsolete and replaced by the one i have right now,  the IXRFD630.

Regards     Itsu

Hi Itsu

no more active I'm afraid, sold all my equipment some years ago after a divorce, only held onto a 2mtr hand held for repeater access. I used to be on HF with a yaesu 101, also 2mtr and 70cm for satalite work which I liked a lot, did try moon bounce at one time, and of course well known for speaking to shuttle crew when in orbit "many many years ago"

Changed my G4 for a Spanish license and held onto my G6 in England, been living in Spain for 25 years now.

Spent a lot on equipment over the years, 10 meter when the sun spot activity was high was really great, had many contacts around the world including royalty of the oil type, not to mention names ;)

The internet has made some people change, radio was a challenge not like today.

73's

-- .. -.- . 8)

Mike, 

thanks for the info, sounds familiar  :)

I was mostly in for 2meter DX (long distance) via Aurora reflection, Sporadic E-layer reflection (Es), Meteor Scatter reflection (ms), tropospheric conditions (tropo)
and did a fair amount of moonbounce, mostly with the big guns from the US/Canada

It was magic to hear your own reflection coming back from the moon after about 2s.
Nowadays they use computer aided programs to "listen into the noise" and show the morse signals on the screen  :o


I am thinking of reinstalling a station (FT-991 looks nice) now i have some extra free time.


Regards Itsu

Quote from: Itsu on 2015.07.04, 09:18:42
Mike, 

thanks for the info, sounds familiar  :)

I was mostly in for 2meter DX (long distance) via Aurora reflection, Sporadic E-layer reflection (Es), Meteor Scatter reflection (ms), tropospheric conditions (tropo)
and did a fair amount of moonbounce, mostly with the big guns from the US/Canada

It was magic to hear your own reflection coming back from the moon after about 2s.
Nowadays they use computer aided programs to "listen into the noise" and show the morse signals on the screen  :o


I am thinking of reinstalling a station (FT-991 looks nice) now i have some extra free time.


Regards Itsu

I would like to set up again but wanting to sell the house and move to a smaller one down by the sea, no money at the moment, times are quite hard here, I retire next year but my wife will continue as she is only 56, so things won't change that much. I am 45km outside Valencia, up in the mountains, would be a good site for DXing.

regards

Mike 8)

Hi Itsu

that is some rig, I have not been keeping up over the years, talk about all included (apart from a 25amp PSU). The touch screen might be a bit small, there are a lot of comments about it, some good some not so good, but that goes for everything these days.

I find one problem with all in one, when you have a fault you are off the air on all bands :(

Oh to be able to afford one, @ 1700$ it is way out of my pocket now. Years ago I had no problem, when I was 35 I probably had 6000 pounds sterling in equipment, different times, different place and a lot of water under the bridge :'(

If you buy it and are throwing out the old ;)  I could recycle it ^-^

regards

Mike 8)

Thanks for the info Mike, i was in the same boat as you 10 years ago, i also sold my stuff then, only have my IC211E for 2 meters.

Enjoying the nice weather here while waiting for my FG to return   :(

Regards Itsu

Quote from: Itsu on 2015.07.06, 20:21:54
Thanks for the info Mike, i was in the same boat as you 10 years ago, i also sold my stuff then, only have my IC211E for 2 meters.

Enjoying the nice weather here while waiting for my FG to return   :(

Regards Itsu

Just poped in, we have arrived in France, was a very hot drive up here, at one point around Lyon a hot 44c wind and a good job we have A/C in the car.

Hope your SG comes back soon, will keep poping back in, though I can't get the hang of these French key boards, takes me for ever to type with them C.C

regards

Mike 8)

SG is back, so i ran a quick test on 13.56MHz with the new IXRFD630 driver and the old FQA11N90C (2) MOSFET's.

While on 4.5MHz this combo is very stable and reach efficiencies in the 90% range, on 13.56Mhz its highly unstable.
Blew one MOSFET and cannot get high output (70W with 24V drain voltage)
Also the current pulled by the driver (800mA at 4.5MHz) increases to 2A on 13.56MHz (similar behaviour as with the older driver IXDD414ci)

It could be my 13.56MHz module, especially the output coils which get hot quick.
Perhaps new output coils of thick litz wire are needed, but it also could be that the MOSFETs simply are not able to handle 13.56MHz.

Screenshot shows gates signal (yellow) and input from SG (blue)


Regards Itsu

Quote from: Itsu on 2015.07.09, 20:31:27
Blew one MOSFET and cannot get high output (70W with 24V drain voltage)

I don't think it is the frequency that killed the transistor.  The gate signal should not be oscillating like that.

It is hard to design a stable MOSFET circuit in RF applications...unless you have one of those (https://www.youtube.com/watch?v=8ziYqjMQGEQ) ;)

That video is a fake LOL
No where in the video do they show the power supply drawing more than 55V @ 9.45Amps or 520 watts

Quote from: Peterae on 2015.07.09, 21:28:41
That video is a fake LOL
No where in the video do they show the power supply drawing more than 55V @ 9.45Amps or 520 watts

That's unfair to NXP.
Note that this average PS input power reading is taken when a "mismatch unit" is connected causing a huge VSWR up to 125:1.
With such high VSWR a lot of RF power is reflected back into the amplifier, effectively decreasing its PS input power draw by the amount that is reflected back.

The full 1.2kW can only be transferred to the load and drawn from the PS,vwhen the VSWR is close to 1:1, meaning reflections are at the minimum and all energy goes to the load and stays there at the expense of burdening the power supply with that RF power, which is what the NRVD Rohde and Schwarz RF power meter indicates at 2m08s (http://youtu.be/8ziYqjMQGEQ?t=2m8s) .

I worked with that power meter and probes and always found them to be very accurate.
An independent Russian engineer also tested the performance of this transistor with a Bird wattmeter (see this video (https://www.youtube.com/watch?v=tWCR7cP6YGA)) and he also got a similar output power reading to the NXP EE with the Rohde & Schwarz meter.

P.S.
NXP is a serious company that stands to lose a lot by making fake videos marketing-wise and lawsuit-wise.  Their customers are mainly engineers and any EE with an RF power meter could prove that their specs were fudged, if they were.

Quote from: verpies on 2015.07.09, 21:06:44
I don't think it is the frequency that killed the transistor.  The gate signal should not be oscillating like that.

It is hard to design a stable MOSFET circuit in RF applications...unless you have one of those (https://www.youtube.com/watch?v=8ziYqjMQGEQ) ;)

I agree with Verpies, there is something up with the gate signal, what does it look like at 4.5MHz? and is the drive to the driver at the same voltage? seems low at 3-4v, have not time to look at the spec, maybe later.

regards

Mike 8)

Changed the output coil to be made from litz wire (2mm thick), amplifier is more stable now, but efficiency still low, 290W in, 220W out (75%).

That litz wire is hard to solder  :o

Will do some more tests tomorrow.

Regards Itsu

Quote from: Itsu on 2015.07.10, 21:11:14
That litz wire is hard to solder  :o

Do you burn off the insulation/enamel from the strands, or do you sand it off ?

Quote from: verpies on 2015.07.11, 01:17:25
Do you burn off the insulation/enamel from the strands, or do you sand it off ?

If it is the "solderable" type, it still takes a lot of continuous heat, flux and patience to get a solid connection.  If it's not, lord help you prepping an end.

Quote from: verpies on 2015.07.11, 01:17:25
Do you burn off the insulation/enamel from the strands, or do you sand it off ?

I assumed its the "solderable" type, as sanding off each of the hundreds of strands is not doable.
As Matt says, it takes a lot of heat, but still then it does not really "flow".

I will try with my 150W iron.

Itsu

When I'm not in a hurry, I use brake fluid with methylene chloride and once the enamel softens I wash it off in acetone and dip it in an overheated solder pot and flux alternately and repeatedly.

most of the enamels are self fluxing these days, you just need the right temperature, too hot and it will burn making it very hard as it will slag up, solder pots are normally the best way as they have large heat mass and even temperatures, though that 150 watt iron you have should do it  O0

I do both, first burn with a flame from a cigarette lighter, and then sand with 400-grit. Then re-bundle and pre-tin before actually soldering to the circuit.

Quote from: TinselKoala on 2015.07.11, 15:44:15
I do both, first burn with a flame from a cigarette lighter, and then sand with 400-grit. Then re-bundle and pre-tin before actually soldering to the circuit.

Cool - that's the same way I do it.

Thanks all for your suggestions, my 150W iron did the trick, it will stiffen up the litz wire for about 4 cm (guess its melting the strands isolation) but then the top is solderable, kind of.


I worked this weekend on the 13.5MHz module, but it is not stable in the setup i have now.
I blew 5 MOSFETs including the 2 new DE275X2-102N06A's (which blew fairly quick compared to the FQA11N90's).
The present driver (IXRFD630) shows like the old one (IXD414ci) a current increase from 0.8A at 4.5MHz to 2A at 13.5MHz (even without a MOSFET), but is able to handle this 24W (specs say 100W), so it does not blow like the old driver (specs say 12W only).

So i guess i will continue on 4.5MHz, as with 82V/6.5A on the drain its putting out 500W.

Video shows 180W output at 41.3V/3.9A (drain) plus 12.5V/800mA (driver) plus 6Vpp 50% duty cycle over 50 Ohm from the SG input.

https://www.youtube.com/watch?v=bQlG4iBtZPc&feature=youtu.be

Screenshot is from this 180W and shows the SG signal (yellow), gates signal (blue) and the output signal (purple).

Regards Itsu

Quote from: Itsu on 2015.07.12, 19:59:40
I worked this weekend on the 13.5MHz module, but it is not stable in the setup i have now.
I blew 5 MOSFETs including the 2 new DE275X2-102N06A's (which blew fairly quick compared to the FQA11N90's).

Did your scope show which MOSFET maximum rating was exceeded, eg.: V_GS, V_DS, I_D ?

verpies,

no, it happens off course in a split second, its drawing the expected drain current, say 4 amps, then suddenly the amps goes up (into the current limiter set to 8A), but then its to late already.
Its always one of the 2 MOSFETs that is defective (not the same), even with the 102N06A's, which is a dual matched pair.

That suddenly can be by adjusting the frequency, the SG input voltage etc.

As the specs on this 102N06A says:

The DE275X2-102N06A is a matched pair of RF power MOSFET devices in a common source configuration.
The device is optimized for push-pull or parallel operation in RF generators and amplifiers at frequencies to >65 MHz.
VDSS=1000 V
ID25=16 A
RDS(on)=0.8Ω
PDC=1180 W

i doubt its the current or heat from it that kills it, also the voltage will not be that high, i suspect my output matching network is not adequate even with the litz wire.
I tune on low power for a nice output sine wave, but even then they drop like flies.

Itsu

So either the V_GS is exceeded or the 1000V V_DS is.  Does Post Mortem ohmmeter measurement show the gate shorted or the drain shorted to source ?

Even the 1000V rating can be exceeded because of resonant rise in your LC network (due to bad tuning).  You should sine frequency sweep (http://youtu.be/_-HdHSvTX2Q?t=1m40s) only the LC network to see its frequency characteristics - a lot can be gleaned from its amplitude vs. frequency plot.

Also, the voltage appearing on the drain influences your gate waveform through the Miller capacitance and/or the power supply line.  The distinguishing characteristic of RF MOSFETs is a very sensitive gate ( low V_GS(TH) and V_{GS ).}

All defective MOSFETs show a short from gate to drain and gate to source and between drain and source.

The 102N06A's both have their left MOSFET blown that way, the right ones look still ok.


Itsu

Quote from: Itsu on 2015.07.13, 12:44:31
All defective MOSFETs show a short from gate to drain and gate to source and between drain and source.

No asymmetry, so that does not tell us much.

Any alteration that decreases these ~40MHz gate oscillations is in the good direction, because some of these ~40MHz peaks can get above V_GS during the fault.  These alterations should be tried at low power, of course.

Yes, that was my thought as well. Got to get rid of that ringing on the Gate signal.

Itsu, is there a photo of the physical layout of the circuit that blows the mosfets?

Well, that 40Mhz signal on the gates was when the 4.5MHz module was in and that runs great, 500W out  at 82V drain voltage at 4.5MHz at 94% efficiency.
I am sure the gates signal with the 13.5MHz module that blows the MOSFETs is much cleaner  :D   But i have no picture of that, perhaps if i look back in this thread i find one.
**** found one back in this thread on page 2, the 13.5MHz gates signal looks like the yellow trace see picture below ****

See below a picture of the layout of the AMP with the 4.5MHz module installed (which as said runs great,)


I am uploading a video right now which shows the sweeping of the 13.5MHz output module as suggested by verpies, its a surprise to me how it looks like.


Regards Itsu

Quote from: verpies on 2015.07.13, 12:28:08
So either the V_GS is exceeded or the 1000V V_DS is.  Does Post Mortem ohmmeter measurement show the gate shorted or the drain shorted to source ?

Even the 1000V rating can be exceeded because of resonant rise in your LC network (due to bad tuning).  You should sine frequency sweep (http://youtu.be/_-HdHSvTX2Q?t=1m40s) only the LC network to see its frequency characteristics - a lot can be gleaned from its amplitude vs. frequency plot.

Also, the voltage appearing on the drain influences your gate waveform through the Miller capacitance and/or the power supply line.  The distinguishing characteristic of RF MOSFETs is a very sensitive gate ( low V_GS(TH) and V_{GS ).}

Ok, did the frequency sweep of the 13.5MHz output module.
I added a 430pF capacitor simulating the both MOSFETs output capacitance (215pF each).
I also added the 24uH RFC with 100nF decoupling capacitor to ground.

input from the SG sweeping 5-15MHz monitored by the blue probe
output across a 50 Ohm resistor monitored by the yellow probe, see screenshot below.

Video here: https://www.youtube.com/watch?v=f_AtENQe6qA&feature=youtu.be

I am surprised to see such a flat response, as i expected to see a distinctive peak around 13.5MHz.


Regards Itsu

Quote from: Itsu on 2015.07.13, 15:00:56
Ok, did the frequency sweep of the 13.5MHz output module.
I added a 430pF capacitor simulating the both MOSFETs output capacitance (215pF each).

That was thoughtful because the transistor's output capacitance is absorbed into the network.

Quote from: Itsu on 2015.07.13, 15:00:56
I am surprised to see such a flat response, as i expected to see a distinctive peak around 13.5MHz.

That's because of the large toroidal inductor, which should be analyzed separately together with the MOSFET's output capacitance and the other cap to ground.
I was hoping to have only the LC network from the TP2 analyzed (frequency swept).  It should have the lowest impedance at 13.5MHz (measured from TP2 to output).

Hmmm,  thats the 4.5MHz output circuit, and i am missing the input capacitor of 450pF

For my 13.5MHz circuit i use these values, see circuit below in red taken from this website / pdf:

http://www.its.caltech.edu/~mmic/reshpubindex/papers/ClassE.pdf

The sweep of it is almost similar as the first one, see screenshot but not sure what you mean by:

Quote(measured from TP2 to output).   

You mean scope probe tip to TP2, and its ground lead to the middle output plug (with or without the 50 Ohm resistor?).

I now have again the blue probe across the input (SG), the yellow across the 50 Ohm output resistor


Itsu

Quote from: Itsu on 2015.07.13, 17:28:38
Hmmm, thats the 4.5MHz output circuit

I forgot to erase the frequency-specific values from the schematic. Done now.

Quote from: Itsu on 2015.07.13, 17:28:38
, and i am missing the input capacitor of 450pF

Exactly. I was not interested in the capacitive reactance of that capacitor (450pF or 150pF) connecting TP2 to ground.

Quote from: Itsu on 2015.07.13, 17:28:38

Quote from: verpies on 2015.07.13, 17:00:25
(measured from TP2 to output).

You mean scope probe tip to TP2, and its ground lead to the middle output plug (with or without the 50 Ohm resistor?).

No, SG-tip to TP2 and scope probe tip to the output (the right side of the schematic).  Grounds of SG and scope connected to the ground of the LCLC circuit.
The 50Ω load resistor present.

Ok,   well "that capacitor (450pF or 150pF) connecting TP2 to ground" is fixed in my module, so i have desoldered it, but without that cap, sweep looks similar as before
see screenshot yellow trace across the 50 Ohm resistor


Itsu

Quote from: Itsu on 2015.07.13, 18:41:28
Ok,   well "that capacitor (450pF or 150pF) connecting TP2 to ground" is fixed in my module, so i have desoldered it, but without that cap, sweep looks similar as before
see screenshot yellow trace across the 50 Ohm resistor

So there is something wrong.
This LCLC circuit should have a different v(f) characteristic.

Let's measure each LC branch individually:
Apply the sine sweep from SG to point B and scope on the output socket with the load resistor present.  You may leave the LC branch between TP2 and point B, hanging in the air, if you do not want to desolder it.
You should see the classical notch LC frequency response of one LC branch.  Note the frequency of the lowest amplitude across the load resistor.

You can also apply the sine sweep from SG to TP2 and scope on the output socket with the load resistor present.  This time, desolder (interrupt) the series LC branch that grounds point B.
You should see the classical bandpass LC frequency response of the other LC branch. Note the frequency of the highest amplitude across the load resistor.

After these measurements you should have two frequency extrema - notch and bandpass, respectively.

something is wrong indeed,  no frequency extrema - notch and bandpass, respectively seen:

first screenshot is SG at point B
second screenshot is without the downward LC at point B

Itsu

Quote from: Itsu on 2015.07.13, 20:03:16
something is wrong indeed,  no frequency extrema - notch and bandpass, respectively seen:

Could it be that the notch and bandpass are so narrow that you are not seeing it on such wide and fast frequency sweep ?
Alternatively, maybe the frequency extrema are outside of your sweep frequency range (i.e. not where you expect them to be).
Finally, maybe some RF capacitors have become shorted or opened.

The notch valley should be centered at the 2nd harmonic and the bandpass peak should be lower than the fundamental frequency.
Why lower and not equal? ...well because when the 450/150pf capacitor and the MOSFET's C_OSS capacitance is connected in parallel and when then this assembly of capacitances is connected in series (yes, in series) between the SG and TP2 in the second test (bandpass), then these additional capacitances will increase the center bandpass frequency, so it is very close to the fundamental frequency.

Zooming in on the frequency does not show a narrow peak/dip

I found the notch frequency (point B) at 20MHz see screenshot 1, no distinct peak seen on the bandpass, max amplitude is around 6.5MHz, but very broadbanded, see screenshot 2

Caps measure ok

Itsu

Quote from: Itsu on 2015.07.13, 21:10:41
I found the notch frequency (point B) at 20MHz see screenshot 1,
Zooming in on the frequency does not show a narrow peak/dip

This notch center frequency should be at 2 * 13.5MHz = 27MHz.  So you can go ahead and correct it right away.

The notch is not narrow because the Q of this LC branch is low.  If you want to narrow it you can experiment with some of the methods listed under the graph below.
All while performing the frequency sweep to see the improvements in real time.

Quote from: Itsu on 2015.07.13, 21:10:41
no distinct peak seen on the bandpass, max amplitude is around 6.5MHz, but very broadbanded, see screenshot 2

I'd say that LC branch is not working.  The Q would have to be incredibly low to exhibit such a wide bandpass.
It should have a much narrower bandpass with a center frequency that is much lower than the fundamental frequency (13.5MHz), when the other capacitors are absent (the 150pF + C_OSS).

You must troubleshoot this LC branch and get a narrow bandpass peak (high Q), the narrower - the better.  This LC branch is much more important than the other branch.

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=19272)

To increase the Q you may try:
- Decreasing the ESR of the capacitor (better cap or paralleling many small caps),
- Changing inductor winding turn-to-turn spacing to 1 wire diameter and trying to keep the coil's length/diameter ratio between 1:1 and 4:1 (see here (http://www.w8ji.com/loading_inductors.htm)).
- Shortening the intercomponent connections,
- Keeping the coil away from other conductors, e.g. the PCB copper laminate (taking it out of the box),
- Minimizing dielectric losses of coil wraps/carcasses/insulation.  Don't put insulation in the space between winding turns.
- Thickening the intercomponent connections (or Litz'ing them),
- More here (http://www.w8ji.com/loading_inductors.htm).

Maybe it's time to start using the FFT math function of the scope, and a slower sweep rate....

His frequency sweeps are already proven to yield good measurement results (see here (http://youtu.be/_-HdHSvTX2Q?t=1m40s) )
Yes, longer sweeps are more accurate but he cannot make them too long, because at long time bases his scope goes into a roll mode ...which is annoying and begs for a firmware update.

The roll mode is active in auto triggering mode, in Normal triggering mode i can go down to any sweep time, presently i have it set to 1s on the Rigol, 100ms on the Tek which shows a nice updating picture.

By the way i am on the latest FW for this scope (2007 version  ;D ).

Thanks for the great info above, i have trimmed down the notch coil to just 1.1 turn (solid 2.5mm² copper wire) and its now dipping on 27MHz.
Its an air coil without isolation or a former.

My capacitors are all silver mica rated 1000V and show an ESR of 3 Ohm on the 1 to 2 nF ones going to 77 Ohm for the lower  (120) pF ones @ 100KHz.

Below:

screenshot 1  a 24 - 30 Mhz sweep.
screenshot 2  a broader (100KHz - 54 MHz) sweep

Itsu

Quote from: Itsu on 2015.07.14, 10:25:21
Thanks for the great info above, i have trimmed down the notch coil to just 1.1 turn

So the length/diameter ratio of this coil is not in the 1:1 - 4:1 range and Q suffers.  See the section Range of Inductor Form Factor (http://www.w8ji.com/loading_inductors.htm) in this article.

You can calculate the Q of your LC branch from the formula below:

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=19279)

Quote from: Itsu on 2015.07.14, 10:25:21
My capacitors are all silver mica rated 1000V and show an ESR of 3 Ohm on the 1 to 2 nF ones going to 77 Ohm for the lower  (120) pF ones @ 100KHz.

That's a lot of Ohms !!

@TK
What capacitors do you use at these frequencies ?

Hi Itsu

still in France but had a thought, I think you need to isolate your output LC when at 13.56MHz, I think there is some feed back through proximity with the driver at the higher frequency, also proximity to the ground plane creating capacitance which also at the higher frequency is detrimental to class E. At 13.56MHz maybe the C of the mosfet is sufficient as I have stated before, at 27MHz it would have to be reduced by a series cap for example.

I think that just with your setup at 13.56 you have been unlucky with your design setup (position) of components :-\

Regards

Mike 8)

Mike,

you might be right, i could try to isolate the input from the output by means of a grounded shield or so.



verpies,

I modified the coils on the 13.56MHz module, see the picture.
The small coil is the notch filter on 2e harmonics (27MHz) and now is in the 1:1 range.
But the big coil (also 1:1) still produces a broad bandpass as can be seen in the screenshot (1 - 11MHz sweep) and shows
a mid resonance frequency of 6.5MHz which if you calculate the LC from here http://www.1728.org/resfreq.htm is right
(The coil measures 560nH with a Q of 8.5, the capacitor measures 1nF)

When looking at this design:  http://www.ixys.com/Documents/AppNotes/CO1.pdf and specific to Fig. 9 see below, then
i think that these designs are identical (they combine the Lt coil and the Lmatch coil in 1 inductor like i have, i only
have the extra notch coil in series with C0 to block the 2e harmonics).

They state that the tank coil should have a low Q like 2, so this means that also there they probably have a broad bandpass (or resonance tank)?

I tried severall different 1nF capacitors, but they all show the same bandpass and ESR (2.5 -3 Ohm).

With other words, i don't think i can get a better bandpass response.


Regards Itsu

Questions, questions questions,  sorry about that.

When sweeping the present series LC tank, see picture, i see a nice series resonance dip (expected / minimum impedance) around 7.5MHz, see the screenshot (100KHz - 15MHz sweep).
Adding or removing capacitors simulating a MOSFET does not influence this resonance point.

To me this means that the series tank circuit works as designed, right?
So then it seems to me that all i have to do is change the L or C or both so the series LC resonate at 13.56MHz, right?

During this measurement the notch leg (LC) was disconnected, but when connecting, there is no impact on this series LC resonance point.
It does influence the amplitude.


Regards Itsu

Quote from: Itsu on 2015.07.15, 10:49:58
To me this means that the series tank circuit works as designed, right?
So then it seems to me that all i have to do is change the L or C or both so the series LC resonate at 13.56MHz, right?

I can't tell from the photo of the PCB where you are feeding in the SG and where you are probing, so I made the schematic below.  The red squares mean breaks/interruptions in the circuit.

If you feed SG to point A and scope across R_L then you should get a bandpass response centered at 13.56MHz.
If you feed SG to point TP2 and scope across R_L then you should get a bandpass response centered at much lower frequency (e.g. 6MHz - 8MHz)

Since the ESR of your C1 is high, then it might be prudent to increase R_L to 500Ω to see the bandpass frequency response during sweeps.
Alternatively, short the output (R_L=0) and scope the notch frequency response across the SG (across point A and Ground).  You may use a 50Ω - 500Ω resistor in series with the SG for its protection.

(http://www.overunityresearch.com/index.php?action=dlattach;topic=3103.0;attach=19305)

Thanks,

i will take a look at it again tomorrow.

My earlier photo of the PCB should show the red SG clip to your point TP2 and its black ground clip to your point B
Also the scope is on those same points, so probe tip to TP2, its ground clip to point B
I was only sweeping the L1C1 tank circuit.


This evening i was studying this design note:   http://users.skynet.be/BillsPage/ClassE030909.pdf
As always, things are more complicated as then first anticipated, and this design is without the notch coil.

I followed those design notes / calculations and not even need the circuit be designed for a specific frequency (13.56MHz),
but also for an intended drain voltage (24V / 40V etc.) and output (100W, 200W etc.).
 
So i calculated my amp. for 13.56MHz and for 24V and 40V  with resp. 100W and 200W output.
2 scenarios come out of that with fairly different values for L's and C's, see below diagram for these different value's.
Q of L1 was measured to be 8.5.

One question came in mind; does it matter if we have first L1 then C1 or vv (using verpies his diagram)?  (it seems that the L-match inductance is being combined with the resonance inductance,
so these 2 L's should be connected and not be separated by C1).


Thanks Itsu

IMO nothing will change if you swap the position of L1 and C1
Of course the mutual inductance between L1 and L2 should be avoided by the usual tricks, such as: orthogonal placement, distance, shielding and so on...

That is not really what i mean, think about a design without the notch coil L2.
The L1 coil is made up of severall (2 or 3) different inductance's, like the main resonance inductance, the phase correction inductance and the L-match inductance.
With C1 in the righthand position, it is in between the first 2 inductance's and the last inductance.

See also my updated post above!

Itsu
 

From your signal path's point of view (from TP2 to Output) the L1 is a series inductor and L2 is a parallel inductor, so they are not the same.  Consequently L1C1C3 forms a fundamental bandpass filter and L2C2 forms a 2nd harmonic notch filter.  If you merge L1 and L2 then the node B disappears and the L2C2 notch filter with it.  The remaining C2 will just form a low pass filter, that will attenuate your fundamental at the output.

Without the L2C2 notch filter your output waveform will have a higher 2nd harmonic content and will be just less clean.

I understand, but you are talking about the design with the L2 notch coil.      

I am talking about the design without such a L2 notch (2e harmonics) coil.


Anyway, i will modify my output module to look like the above diagram (post #145) with the 24V / 100W values in green (as my L1 coil is close to the needed 519nH (now 560nH)),
so without the L2 notch coil to keep it simple (deal with the harmonics lateron).

Thanks,   Itsu

I extensively tried severall output configurations for 13.56MHz, but none seems to be stable.
So there is something wrong in my setup, most probably the used shunt / output circuit capacitors.
I will redo my setup using ATC 100c series of RF capacitors (which are very hard to get) and use known workable MOSFET and drivers together with a new layout (input / output compartments with a grounded shield across the MOSFET input (gate) and output (drain)).

But this will take some time.

Regards Itsu

Still trying to order some ATC 100C series RF capacitors, but either all sales reps are on vacation or they are not interested in me.


Meanwhile i was looking for a FG chip capable of 13.56MHz and found one in this Max038 chip.

It has 2 outputs, one, +/- but at only 2.3Vpp and two, a sync output with an all + signal at 4Vpp.
Unfortunately the sync output duty cycle cannot been changed and is about 64% which i guess is to much.

So need to find a way to amplify/modify the +/- signal.

Screenshot shows the 2 outputs,  yellow the +/- signal, blue the sync output

Video here: https://www.youtube.com/watch?v=-A9cm2M7-WA&feature=youtu.be


Regards Itsu   

Quote from: Itsu on 2015.08.05, 20:58:25
So need to find a way to amplify/modify the +/- signal.

Itsu, can you use a pot as a voltage divider and just level-shift this output on the ground/reference side?

It would be pretty close to 5Vpp.

Quote from: Itsu on 2015.08.05, 20:58:25
It has 2 outputs, one, +/- but at only 2.3Vpp and two, a sync output with an all + signal at 4Vpp.
Unfortunately the sync output duty cycle cannot been changed and is about 64% which i guess is to much.

Forget the sync output.
Amplify and DC level shift the ±2.3V square signal with an op-amp or if you do not have one - with a small MOSFET driver connected to the SG chip by a series capacitor to its input and a weak 2.5V voltage divider after the cap (for DC level shifting).  You just have to make sure that the V_{IN_H} logic input threshold of this driver chip is not more than 2V (for example the UCC27321 we once used has this threshold).


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For your interest

http://www.israel21c.org/spilled-water-inspires-renewable-energy-startup/?utm_source=Israel21c+Weekly+Newsletter&utm_campaign=2a6f0de265-weekly_newsletter_5_8_15&utm_medium=email&utm_term=0_a2ed5ed71b-2a6f0de265-250415557

Itsu

I would not worry about using 13.56Mhz at the moment, go along with the 4.5Mhz+-  we will shield the reactor so as not to emit Rf to the world ;)

I have just been informed in the last week that someone in the USA is going to fire up in the near future my old system of RF splitting of H2O.

I think once it is realised what it is that causes the RF to split the molecule, it can be done quite a lot easier :)

regards

Mike 8)

Thanks Matt,  thanks verpies,


i used a 2.2nF capacitor on the output of the max038 and used the suggested voltage divider (2x 1KOhm between point 1 REF (=2.5V) and ground) after the capacitor.
The signal can be seen in the first screenshot yellow trace, but.... i had to lower the frequency to around 10Mhz for the ucc37322 to show an output, see again first screenshot blue trace (ucc37322 is at 5V Vdd).


Adjusting the duty cycle and frequency to obtain a 50% duty cycle on the output of the ucc even lowered the frequency to about 9MHz, see screenshot 2.
So i guess the ucc37322 chip is not useable on 13.56MHz, right?

Looking at an ixdd414 driver (which i have) shows that the Vin_H is to high (3.5V), so not useable i guess, so need another fast low input driver





Mike, thanks for the info.

the 4.5MHz layout was not really stable as well, so i need to redesign the Amplifier setup and used RF capacitors.

It seems as if the ATC guys are reading this thread as a sales rep. contacted my yesterday and pointed me to how to order their 100C series of caps.  
Unfortunately they do not sell them in kits, nor do they have in stock many different values, just 27pF, 56pF and 100pF (2500V).



Regards Itsu
 

I have a few Motorola MC1590G op-amps that I could donate, if that would help.

Quote from: Itsu
So i guess the ucc37322 chip is not useable on 13.56MHz, right?

It could be if you were to operate your Power Amplifier stage
as a doubler or a tripler.  Those circuits were quite popular in the
early days of radio.

As a doubler, a drive signal of 6.78 MHz would produce the desired
13.56 MHz output.

Push-Push Doublers are sometimes used to advantage.

Quote from: Itsu on 2015.08.07, 20:04:02
So i guess the ucc37322 chip is not useable on 13.56MHz, right?
Looking at an ixdd414 driver (which i have) shows that the Vin_H is to high (3.5V), so not usable i guess, so need another fast low input driver

Right.  That other fast input driver/buffer does not need to be very strong as its only job will be to drive the IXDD power driver.  An op-amp would work, too.
Also, I would adjust the DC level shifting voltage divider after the cap so the lowest excursions of the waveform are closer to 0V (ground).

QuoteI have a few Motorola MC1590G op-amps that I could donate, if that would help.

Thanks for the offer Tinsel, i keep that in mind, i still have some other drivers i could try like a ucc27511 (little bugger   :( ) which has better specs (3nS).

QuoteIt could be if you were to operate your Power Amplifier stage as a doubler or a tripler.

Good suggestion muDped, if all fails i could try that.

QuoteAlso, I would adjust the DC level shifting voltage divider after the cap so the lowest excursions of the waveform are closer to 0V (ground).

verpies,  ok, so use a potmeter instead of the fixed resistors



Thanks guys, i will get it to work this way.

Regards Itsu

Why not. A multiturn pot would work well. Just don't use a 100ohm pot because such small resistance will attenuate the signal amplitude too much.

Quote from: verpies on 2015.08.08, 10:33:07
Why not. A multiturn pot would work well. Just don't use a 100ohm pot because such small resistance will attenuate the signal amplitude too much.

Like this

regards

Mike 8)

I used a 10K potmeter to DC shift the max038 output, and fed this into an ucc27511 MOSFET driver.

This seems to be able to handle the 13.56MHz ok, see screenshot.
Yellow is the voltage divider output, blue the ucc27511 driver output (5V Vdd).

I had to adjust the frequency, duty cycle AND the DC shift potmeter (slightly elevated from the zero line) to get to an acceptable 50% duty cycle on the ucc27511 output, see video:

https://www.youtube.com/watch?v=mNzlano5b00&feature=youtu.be  

Thanks,   regards Itsu

Quote from: Itsu on 2015.08.08, 20:05:20
I had to adjust the frequency, duty cycle AND the DC shift potmeter (slightly elevated from the zero line) to get to an acceptable 50% duty cycle on the ucc27511 output, see video:
https://www.youtube.com/watch?v=mNzlano5b00&feature=youtu.be  

Looks like you solved it without an op-amp.
Centralflow's method might work even better if you have a little signal transformer handy.

Now you can drive the big IXDD MOSFET driver with the signal coming out of the small UCC driver.

Well, i still have the IXRFD630 driver in my setup which survived all the blowed MOSFETs.
I will start with that one and a fresh DE275X2-102N06A MOSFET, but need to rearrange the Amplifier layout.

http://www.rfmw.com/datasheets/ixysrf/IXRFD630.pdf
http://www.farnell.com/datasheets/1019384.pdf

Regards Itsu

Since FET's usually only require a very small voltage change to go from full on to full off, the trick is biasing the gate into the conduction threshold and level shifting the signal with an ordinary capacitor. The normal output of the Max 038 should provide sufficient drive once level shifted, since you will be toggling +/- 2.3 V0lts right around the FET threshold voltage. Maybe you are already doing this. Best to adjust the pot so that the FET is "just off" with no signal, In this way, the pot does not attenuate the Max038 output and you get the full voltage swing at the gate. You can still use the UCC FET driver if inserted properly between the bias circuit and the gate.  Then you are level shifting to the required input of the UCC part instead of the FET gate. Values needed may differ slightly from those shown, but these should work.

Quote from: ION on 2015.08.09, 12:49:50
The normal output of the Max 038 should provide sufficient drive once level shifted, since you will be toggling +/- 2.3 V0lts right around the FET threshold voltage. Maybe you are already

Yes, biasing just below the V_GS(th) will save some energy, but not enough to operate at 13MHz ...and it will make the MOSFET susceptible to Miller turn-on if there are high dv/dt waveforms at the drain.
The turn on region is not a point.  Just to overcame the Miller plateau, which occurs above V_GS(th), requires significant charge to be delivered to the gate that the MAX038 simply cannot deliver at the necessary rate.

Quote from: verpies on 2015.08.09, 15:17:52
Yes, biasing just below the V_GS(th) will save some energy, but not enough to operate at 13MHz ...and it will make the MOSFET susceptible to Miller turn-on if there are high dv/dt waveforms at the drain.
The turn on region is not a point.  Just to overcame the Miller plateau, which occurs above V_GS(th), requires significant charge to be delivered to the gate that the MAX038 simply cannot deliver at the necessary rate.

I didn't look closely at the MAX038 data sheet and therefore you may be right, I was just trying to get some ideas across about level shifting as commonly used in industry. The driver chip is a better way to go with the capacitive level shifter.(second scheme).

Besides enjoying the summertime and my free time, i was rebuilding my 13.56MHz amplifier.
The layout has been changed 90° and there is a grounded shield between the input and output compartments across the MOSFET, see picture.

Also the output circuit has been changed according to this design:   http://www.ixys.com/Documents/AppNotes/CO1.pdf

I have SMD multi layer RF capacitors (2Kv) and a 4 turn copper strip inductor around 2x T256 toroid's.

The output circuit sweeped with the FG attached to the MOSFET drain / source and the scope attached to the unconnected output plug (no dummy load attached).
shows a peak around 13.7MHz which is fine for me now (it will dampen down when the 50 Ohm dummy is attached) see screenshot.
(sweep is from 10.7Mhz to 16.7Mhz)

Presently i am still waiting for a new IXRFD630 driver as i don't trust the old one after blowing up many MOSFETs.

Hopefully this rebuild will be more stable as the old one, which i will let you know.


Regards Itsu

Why was the Litz wire winding substituted with the copper tape ?

Quote from: verpies on 2015.09.11, 23:07:44
Why was the Litz wire winding substituted with the copper tape ?

Nice as always Itsu, we will see how she runs

For me, using tape is far better as at these powers "1Kw" the possibilities of a wire break in the litz is high, this will change all the characteristics of the output "which is very sensitive in class E". Also you do not need to contend with the self capacitance of a litz wound coil which causes tuning problems "at these power levels". low power is another thing.

The SS is not showing the 13.56Mhz running frequency, or have I missed something :-\

regards

Mike 8)

Quote from: verpies on 2015.09.11, 23:07:44
Why was the Litz wire winding substituted with the copper tape ?

As i wanted to follow the output section as mentioned in the PDF design as close as possible.

Regards Itsu

Quote from: Centraflow on 2015.09.12, 07:54:18
Nice as always Itsu, we will see how she runs

For me, using tape is far better as at these powers "1Kw" the possibilities of a wire break in the litz is high, this will change all the characteristics of the output "which is very sensitive in class E". Also you do not need to contend with the self capacitance of a litz wound coil which causes tuning problems "at these power levels". low power is another thing.

The SS is not showing the 13.56Mhz running frequency, or have I missed something :-\

regards

Mike 8)

Mike, i guess with SS you mean screenshot.

The screenshot shows the response of a continuous sweep from my FG of a sine wave signal running from 10.7Mhz till 16.7Mhz (center 13.7MHz).
The scopes frequency calculation is not accurate this way and i should had to remove that, so please ignore it.

The screenshot shows an unloaded bandpass around 13.7MHz of the output section, which is what we want.

Regards Itsu

 

Quote from: Itsu on 2015.09.12, 09:51:43
Mike, i guess with SS you mean screenshot.

The screenshot shows the response of a continuous sweep from my FG of a sine wave signal running from 10.7Mhz till 16.7Mhz (center 13.7MHz).
The scopes frequency calculation is not accurate this way and i should had to remove that, so please ignore it.

The screenshot shows an unloaded bandpass around 13.7MHz of the output section, which is what we want.

Regards Itsu

 

Ahh, thought I'd missed something, it was the frequency of CH1 @4.    Mhz that threw me off O0

regards

mike 8)

Quote from: Centraflow on 2015.09.12, 07:54:18
For me, using tape is far better as at these powers "1Kw"

How can it be better when the 13.5MH RF current flows only in the upper 0.08mm layer of the copper tape before it gets attenuated by 98% ?
Compare the conductivity of a 100 strand Litz wire of the same cross sectional area as the copper tape and show me the quantitative comparison.

Quote from: Centraflow on 2015.09.12, 07:54:18
the possibilities of a wire break in the Litz is high, this will change all the characteristics of the output

The chances of a Litz strand breaking spontaneously are minuscule and even if that happened, the inductance of the coil would not be affected and 99% of it conductivity would remain.

Quote from: Centraflow on 2015.09.12, 07:54:18
Also you do not need to contend with the self capacitance of a litz wound coil which causes tuning problems "at these power levels". low power is another thing.

There is no self-capcitance between different strands of a Litz wire because they are at the same potential.  There is only the self-capacitance between turns of a winding, because different turns are at different potentials. Capacitance is proportional to the surface area of a conductor at different potentials and a tape has more surface area than a cylinder (round wire) of the same conductivity.

The turn spacing is another factor that affects the self-capacitance of a coil but I don't see how this spacing would be larger with a tape.

Quote from: Itsu on 2015.09.12, 09:43:54
As i wanted to follow the output section as mentioned in the PDF design as close as possible.

I can respect that.

Note that your winding has a very high pitch which creates large ratio of circumferential current to toroidal current.  This results in a large leakage inductance.
A winding that was wound like that with a Litz wire, would create the same circumferential current component and large leakage inductance, so this particular problem is not of the wire vs. tape variety but of a winding geometry.

Leakage inductance affects the Q negatively.
From the frequency sweep I can see that the Q is much better now, compared to the Q of your old build (more narrowband freq. response), but I attribute that difference to these new better capacitors.

An inductor employing foil windings combines the very low dc resistance of a copper foil with the
low ac resistance of a Litz-wire winding. In particular, for high-current, high-ripple inductors, the shaped-foil winding can be the lowest-loss solution.

In other words for what we want here it is better than litz, at low frequencies and low power litz would probably be better :)

Regards

Mike 8)

Quote from: Centraflow on 2015.09.12, 14:28:03
An inductor employing foil windings combines the very low dc resistance of a copper foil with the low ac resistance of a Litz-wire winding.

It does not "combine" it, it trades it off.

Quote from: Centraflow on 2015.09.12, 14:28:03
In particular, for high-current, high-ripple inductors, the shaped-foil winding can be the lowest-loss solution.

Yes, but not for high frequency inductors.  The 99% skin depth for copper at 13.5MHz is only 0.089mm so any copper located deeper than that does not participate in AC conduction and is utterly wasted.  However most of the copper in a Litz wire with 0.05mm strands will participate in AC conduction.

Quote from: Centraflow on 2015.09.12, 14:28:03
In other words for what we want here it is better than litz, at low frequencies and low power litz would probably be better :)

No, at low frequencies the skin depth increases so more of the copper participates in AC conduction.  At DC the entire copper participates.

For example, at 1kHz the 99% skin depth in copper is over 10mm, so almost an entire 0.1mm thick copper tape participates in the AC conduction, while at 13.5MHz only 35% of copper participates in AC conduction in such tape.

@ Verpies

OK I'm still learning, I'm not a professional :)

regards

Mike 8)

But there still must be a reason for the professionals to use it :-\

The copper strip i am using is 0.2mm thick and 1cm wide and i was meaning to silver plate it like in the PDF using this stuff:

http://www.homecareessentials.co.uk/acatalog/1Silver_Plating_Polish.html

It will increase conductivity for another 3% as i understand it, however not sure the above silver plating will be thick enough.


I can always use the litz wire (i got 10m) when efficiency stays low.
I also have 0.8m of 2mm diameter silvered copper wire which i can use.

But first of all, i would like to have a stable 100W output with this setup.


Regards Itsu

Quote from: Centraflow on 2015.09.12, 17:43:54
But there still must be a reason for the professionals to use it :-\

There is a good reason to use tape windings at low frequencies.
Also, a thin tape works better at higher frequencies.  
There is also a technique that electrochemically deposits many layers of silver and a dielectric alternately and such sandwich collectively has a very high equivalent AC conductivity (admittance).

There is also the issue of the proximity effect which makes the admittance even worse than with the skin effect alone.
I can calculate the skin effect very precisely but I cannot do the same for the proximity effect, which is unfortunate because the proximity effect usually dominates the skin effect.

IXRFD630 MOSFET driver also received and installed.

12.5V input voltage on this driver, direct connection between its output and the MOSFET gates as recommended by the datasheet.
Input signal is 13.5MHz 2.3V positive square wave 50% duty cycle, so i expected to see something like 12V square wave signal on its output
Instead its a 24V terrible shaped signal

Output into the dummy load seems ok 120W, however, the DC input / RF output relationship does not add up.

Anyway, its a start.

I have some 18V TVS which i could install across the gate/source, but i am not sure they can handle this output and/or the frequency
1.5KE18CA  

Screenshot shows:
yellow: input across the 50 Ohm input resistor attached to the input pin of the driver to ground
blue: signal on the gates of the MOSFET.

Video here:   https://www.youtube.com/watch?v=Mfucvo-C7Ms&feature=youtu.be

Regards Itsu

Quote from: Itsu on 2015.09.19, 19:08:22
i expected to see something like 12V square wave signal on its output Instead its a 24V terrible shaped signal

If the amplitude of the gate signal varies together with the supply voltage applied to the drain, then you will know, that the extra gate voltage comes through the Miller capacitance between the drain and the gate.
Otherwise you have some parasitic inductance around the gate driver.

Thanks verpies,

its almost inevitable to have some parasitic inductance as the minimum distance between a Vcc lug and the nearest ground lug is 1.6cm, while a decoupling cap is only 2mm, the rest are wires (inductance).

Regards Itsu

Without a drain voltage on the MOSFET, i still have this badly shaped 26Vpp output signal on the drivers output lug and the MOSFET gates,
so to me this means that its not the miller capacitance that drives up that voltage.

I rearranged the drivers voltage (12V) return lead to be on the Vcc side and use very short wired caps (4 parallel on each Vcc lug)
to decouple the Vcc to this return/ground.

Caps used there are 4x 0.1uF parallel, 10uF tantalum and a 1nF wima.  This is on each Vcc lug

But even now i have a similar signal in the 26V pp range (13.5MHz).
Adding the 18V TVS across the gate/source of the MOSFET lowered this to about 22V pp, but still badly shaped.
So still struggling with this driver to get a decent signal out and into the MOSFET.


Regards Itsu

Quote from: Itsu on 2015.09.20, 20:55:45
Without a drain voltage on the MOSFET, i still have this badly shaped 26Vpp output signal on the drivers output lug and the MOSFET gates, so to me this means that its not the miller capacitance that drives up that voltage.

Yes, you eliminated that cause.


Could you have a scope grounding issue?

I used my RF probe tip (you know the slip-on spring-like ground thingy) today, but the signals are still as bad.
I am almost sure it has to do with the decoupling of the 12V supply voltage (battery), so i will try some variations with some caps.
I see a distinct 42MHz signal ontop of the input signal (independent of the input frequency), so there seems to be a inductive loop somewhere.

Regards Itsu   

i made some improvements on the MOSFET driver Vcc decoupling and added the 18V TVS on the gate again.
The input and gate signals are better now and the amp seems stable.
Next is to use the powerpack to supply 48/53V and a Dc2DC converter (48V to 12V@10A) to power from this also the driver.
Hopefully i will reach the 300W output so i can continue to the next step.

Video here: https://www.youtube.com/watch?v=wi4sbldNbf4&feature=youtu.be


edit: a quick test shows with the powerpack on (53.3V) it pulls 6A and shows 350W on the output meter, so its look enough.

Regards Itsu

Did you ever do any "water burning" with that 13.5MHz 350W output ?

Nope,  no water burning attempted.

It was a great project, and i learned a lot, but the thing is not very stable.
Pumping 350W into a 50 Ohm dummy load is OK, but i don't see how to open the line and insert a tube of seawater in the stream without creating havoc on the final stage and thus blowing it.

I would need a much better variable impedance matching system (antenna tuner) between the Amp. and this tube insertion setup then the fixed matching setup i have now.

Perhaps when i run into some coils/caps i could build something and continue with it.


Itsu