Testing ION's Bifilar Circuit with Bias

[Peterae]

OMG it works ION  

I am getting +4000V positive spikes and - 2000V negative spikes on my bias coil which is driven from a dc supply with chokes at each end, i am uploading pictures and video shortly.

I am driving from a variable LOPTX with 1Kv gaps at each end of the system.

[Peterae]

I need more current on my bias i can only drive up to 2.5V before i reach it's 1amp limit.

I am using enamelled wire for each bifilar coil and red & black insulated wire for the bias coil.

The bad news it looks like this is just capacitive coupling because i can turn my bias off and i still have the pulses  

Here's a video on me altering the HV voltage and thus varying the gaps fire speed
I'm using a x1000 probe and each div is 2kv

[Peterae]

Yeah downgrade that last WOW  

I am not even sure the iron delay is working, the iron losses are high and the capacitive coupling between my bifilar coils is high, i don't think this is doing me any good for a pulse through the iron delay.
I think the bifilar coils should be far enough apart to minimize capacitive coupling but close enough to allow the inductive coupling remain fairly high.

On an up note those positive pulses on the bias coil could potentially be harvested.

[Grumpy]

How much iron wire is needed for a 220ns delay? (I know it is based on several other factors as well, but just wondering about the general length required)

[Peterae]

I cannot remember i built it years ago, it's variable about 3 meters of iron wire and i just crock clip down it's length, maybe i should switch to coax

[Peterae]

Just found a paper about using coax for a delay line, it looks to me that you only get a couple of nS per metre length if you are lucky.

I have a cunning plan though, no separate delay line is needed it can be built into the bifilar itself

[Peterae]

So here's coil 2

Not sure if this will work but here's the plan

I have 2 CD's around each periphery i have taped kanthanl wire, each CD can be rotated with respect of each other thus altering the phase between each CD wire starting position, now this puts me in a position where i can run each wire either in parallel or even series and still get variable phase adjustment.

and because i can run the bifilar coils in series or parallel i can now connect my choke at each end and feed with a DC bias, then connect my spark gaps on the kanthanal sides of the chokes and pulse from a single sparkgap.

I had to use Kantanal for the moment as i cannot find my iron wire from years back, and i tried the method ION mentioned about unwinding the coiled but i first had to soft anneal the wire over the gas hob burner.

[Grumpy]

Just found a paper about using coax for a delay line, it looks to me that you only get a couple of nS per metre length if you are lucky.

I have a cunning plan though, no separate delay line is needed it can be built into the bifilar itself

I suggested just a cap and inductor initially, rather than the iron wire.

Same here, can't find my iron wire - it was a nice spool of wire for use in a garden for tying vegetables.

[Peterae]

it was a nice spool of wire for use in a garden for tying vegetables.

LOL yeah i had a 50 meter reel it has green insulation over the iron wire, dam i wish i knew where it is  

[BEP]

Peterae,

Do you recall the little strip delay lines used in earlier TV video?

I believe they could go up to 2ms and were very small.

I've seen the spiral version rated for 10ms (probably what was used in the ESL speaker system.)

Neither used iron as any part. I know the small strip line had a solid copper rod or strap for a core. Both used lumped circuit design.

>>Edit..

The ESL delay spirals may have had iron in them but the spiral delay lines I've used/built do not.

[ion]

Iron as a delay element is probably a poor choice. I have not researched whether a variable inductor or variable cap or some combination thereof would be better or worse in terms of stability vs. temp.

Air core strip delay lines as used in older TV's might be good as WW points out, however they have large ohmic losses and would be a lossy item in a Hi Q circuit, but perfectly acceptable if used correctly.

Tektronix used coax transmission line in some of their older scopes for delay.

[BEP]

A ferromagnetic wire isn't a bad choice if supported in a way to allow it to use sonic velocities for delays. -- in air or cork.

Some of the frequency information provided related to TPUs would work well with the circumferences calculated if any wave velocity was at sonic speeds.

[Grumpy]

I have to research it, but I think the delay provided by coax is dependent on the dielectric, so a clever choice of material may net us a suitable delay in a short length.  Typical coax will require 100 feet or more.

[Peterae]

Do you recall the little strip delay lines used in earlier TV video?

Bearing in mind we use PAL in the UK

I have seen 3 configs in TV's for delay lines
1 very compact chroma delay which uses a core and coils, not sure fully of the build config, they are compact and were mostly used in videos.
2 a long rod with very fine copper wire wound down it's length also Incorporated fine copper foil, these were used in early TVs for the chroma delay line.
3 Flat rectangular construction, which house a glass plate, ultra sonic transducers were used to fire sound waves through the glass medium at angles, the sonic wave bounces off the glass edges until it finally reaches the ultrasonic receiver transducer, commonly used in luminance delays.

A chroma delay gives about 64uS and a luma delay gives 1-2uS

I am hoping that by rotating the 2 Cd's i can vary the phase and then not need a delay line   Not yet sure if it will work

[Peterae]

first tests tonight, with the 2 kanthal rings in series & bias applied each end of the series rings.

Nothing really unusual noted, i have tried using one on my spare Romero motor coils with a ferrite in the middle as a sniffer, now the strange thing is that it does not matter where i place this sniffer i can pick up spikes and as i get closer to the kanthal rings the amplitude goes up but if i flip the sniffer coil over it still detects the pulses with the same polarity, i would have thought if it was a magnetic pulse i was sniffing it should switch polarity when i switch the sides of the sniffer coil.

the only other thing i can note is the fire rate slows with the bias on, same if i flip the polarity of the bias voltage.

Also altering the position of 1 disk to the other i can not really detect any changes

[Grumpy]

For the dealy element, I had something like this in mind: (see attached)

[Peterae]

I think that's what is used in the more modern chroma delay lines, apart from the digital ones that is.
Your biggest problem i think will be attenuation and working voltage, i guess you could refine your build on a simulation though

[Grumpy]

I think that's what is used in the more modern chroma delay lines, apart from the digital ones that is.
Your biggest problem i think will be attenuation and working voltage, i guess you could refine your build on a simulation though

One of the lements will have to be tuned, but the values are low so no huge coils or caps to deal with.

[Peterae]

I rewired for parallel kanthal coils and tried varying the rotation of each CD, i could not see anything unusual.

The problem here is i am picking up wide band electric fields all around the disc, for instance the sniffer coil does not again show a reversal of waveform when it's flipped 180 degrees, if there was a prominent magnetic component this should be prominent enough to see a difference when the sniffer coil is flipped over, the other thing is capacitive coupling of large metal objects and the ability for them to pick up the wide band noise much more efficiently, for instance i tried an alinco magnet and a reel of solder, both showed a much increased amplitude picked up by the scope probe.

HV pulsing using the spark gap's is not the answer, i need high current not high voltage bursts, i believe this is where the magic effect will be found if anywhere.

[Grumpy]

Don't expect a magnetic component.

[EMdevices]

A ferromagnetic wire isn't a bad choice if supported in a way to allow it to use sonic velocities for delays. -- in air or cork.

Some of the frequency information provided related to TPUs would work well with the circumferences calculated if any wave velocity was at sonic speeds.

Delay lines are quite common even nowadays,  I had to go to the DMV to renew my driver licence and encountered quite a delay line.