Magnetic Resonance Devices based on Don Smith Concepts

[Yucca]

Hi Yucca

Thanks for the comments.
I used grommet strip, see my post and picture on page 12 of this thread.
the grommet strip is quiet flimsey.
First i found a 3 inch tube, and it so happened i had been given a bottle of Glenfiddick Whiskey which came in a 3 inch carboard tube, so i first drank the whiskey over a 7 day period HICK Still got hangover LOL

I then tapped the grommed strips around the circumference, used a bakebean can from asda LOL to wind the coil first, i then transferred the 20 turn coil onto the Tube and into the grooves of the grommet strip.
I then applied 5 min epoxy glue into the grommet channels and let it harden.

I trimmed the ends of the coil noting how much length i took off to work out the final wire length.

The wire i used is tinned, i used this incase the enameled stops coupling to the atmosphere.

gyulasun
Thanks for this information it answers all my questions about how to use the GDO just need to get some hands on now
The radio idea is great and will enable me to check the higher freq acuracy.

Yucca great stuff with the hands on looks like i may need a better Sig Gen as mine only goes to 12mhz 

Very interesting the bridge doesn't alter the res freq.

Hi peter, the grommet strip worked great, I will get some for my next secondary coil.

MY HV diodes weren't conducting at the voltages being swung and showed no noticable extra C. I left the wires in place, but just disconnected them at the bridge connectors.

Maybe tuning this device is as simple as first get natural resonance of the secondary coil/s and then tune the primary to match, just like regular T coil only were working with more manageable output voltages.

I was lucky with my sig-gen recently on ebay usa:

Tektronix:
TM503 modular instrument cab with PSU
FG504 Func Gen(0...40MHz 10nS rise into 50 Ohm)
PG501 Pulse Gen(0...50MHz 10nS rise into 50 Ohm)

I gambled and bought it untested with no warranty or return policy, $160 + $60 ship to Eur. The seller didn't even know what it really was. When I turned it on first a thick plume of brownish smoke rose from the PG501, gutted!, but it was just a snubber cap across that must have gone short in storage, luckily everything works fine now and I've cleaned it inside and out and made a new main knob for it. Here's a pic I carry in my wallet

[Peterae]

Yucca
What a bargain nice 1.

I was bidding on a 1nF 2kv variable cap on ebay tonight but had to go out and was outbid  ebay certainly can give up some bargains sometimes.

[Yucca]

Yucca
What a bargain nice 1.

I was bidding on a 1nF 2kv variable cap on ebay tonight but had to go out and was outbid  ebay certainly can give up some bargains sometimes.

Peter, was that cap air or vacuum. If air then you probably wont get much more than 15MHz through it, which might well be good enough. Vacuum caps go easily up to 30MHz, but they're so damned expensive.

Maybe if your sig gen has square pulse then you could always hit the coil end with just the signal gen line at say 100kHz (no ground connection). Then putting your scope probe down on the bench say 4 inches away you may see ringdown at natural resonance freq.

[Peterae]

Yucca
yer it was air, i didn't realize they had a top freq, it's amazing how much we need to know when building this stuff, a fantastic way of learning anyway.

Wow just looked up Vacuum caps they look amazing, how do you adjust them?

Edit OH i see they still have an adjuster, i guess you fit a knob to the shaft


JENNINGS TECHNOLOGY COMPANY VACUUM VARIABLE CAPACITOR
• PN: CMV1-1000 - 0103 • Capacity Range: 8 - 1000pF
• Voltage (KV) Peak Test 3KV Test 3KV Working
• Current Amps (RMS) Max. 40A
• Type: Ceramic • Length: 4.33”
• Diam: 1.78” • Capacity vs Turns 10t = 8pF   0t = 1000pF
• Drive on TOP: Please Note, this is not ¼" Shaft, but a special "Spline" Cog Type Drive!! Click for large photo
• Frequency: 2 - 30MHz
• Brand New Item / Never been used. Unusual and very hard to find!
• Price:£125 (5pcs available) Click for large photo

[stprue]

@Yucca & Peterae

What do you think of this little test!!!  It is kinda like a small tesla hairpin circuit.  The interesting thing about it is that it is lighting an led on a different JT circuit...no contact.  Also you can see voltage reading off my DMM that's connected to my JT!  What are your thoughts on this?