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Michael W.

Sat Mar 25 2006, 04:19AM

Registered Member #50 Joined: Thu Feb 09 2006, 04:07AM
Location: Vernon, B.C, Canada
Posts: 324

Is there a way to tune a SGTC to exchange arcing for RF output or less arcing and more RF? How could I hook my osciliscope up to my coil to tune it? (Yes, I know, a very newb question, but I just got a scope today)

EEYORE

Sat Mar 25 2006, 04:33AM

Registered Member #99 Joined: Thu Feb 09 2006, 06:10PM
Location: florida, usa
Posts: 637

Put a large topload on to supress streamers, this should inturn boost the RF output rather than streamer growth.

As for tuning with an o-scope, you can roughly measure the Fres of your secondary by hanging your probe nearby and reading the waveform freq while the coil is running.

Matt

teravolt

Sat Mar 25 2006, 04:52AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

teslas and electronics don't mix so be mindful. Also he is right just start at 5 feet and move in slowly if tesla is active. moast scope chanels can't take above 400Vdc. good luck.

Michael W.

Sat Mar 25 2006, 05:06AM

Registered Member #50 Joined: Thu Feb 09 2006, 04:07AM
Location: Vernon, B.C, Canada
Posts: 324

obiously i'm going to feed it with a signal generator...

Hazmatt_(The Underdog)

Sat Mar 25 2006, 05:46AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

I have a HV divider, and EVR does too. Mine is a tandom unit which is easy to construct, but it needs to be calibrated to some known value to be accurate. They work well provided the ringdown isn't so horrendous that it goes off the screen. I had to recalibrate mine to 1,000,000:1 because of ~160,000 V oscillations, it was pretty wild. Anyways, as long as the case is well grounded, and you provide enough isolation, it's really not that hard to make a direct measurement.

HV Enthusiast

Sat Mar 25 2006, 03:36PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Even if you supress arcing, you are going to put out little in the sense of RF. If you really want to put out RF with a tesla coil, then go for a solid state coil running CW mode. Then you'll get significant RF output. But with a disruptive coil, you just won't get much, not to mention that a tesla coil is very poor as an antenna.

Marko

Sat Mar 25 2006, 04:47PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Depends what do you consider as ''RF output'' , EM emission or electric field?
As EVR says TC is rather poor antenna and it cannot generate significant EM field compared to horrid (altering) electric field (this actually jams our scopes, instruments, lights up neon bulbs and other things at distance).
It is actually far stronger with pulsed TCs but happens in short bursts, with SSTCs you have CW emmision of 'weaker' electric field.

Since you only want to measure th coil with scope hook it to signal generator, and move the scope probe closer until you have clear signal.
grounding other electrode of probe and increasing surface of metering probe will increase voltage you sense.

yust dont power the coil up and measure it from safe distance.

Michael W.

Sun Mar 26 2006, 12:27AM

Registered Member #50 Joined: Thu Feb 09 2006, 04:07AM
Location: Vernon, B.C, Canada
Posts: 324

Tesla Experimented with huge RF fields (it was said that horses running at night, corona could be seen streaming off their horse shoes to ground.) I don't beleive he had trasistor based tesla coils, so how did he produce such fields?

HV Enthusiast

Sun Mar 26 2006, 01:07AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

wrote ...

(it was said that horses running at night, corona could be seen streaming off their horse shoes to ground.)

There is no proof that any of these extraordinary claims actually occurred.

Marko

Sun Mar 26 2006, 12:04PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Tesla didnt actually do anything magical or special.
It is told that when he ran his huge magnifying transmitter electric field was so intense that you could get tiny burns from ungrounded objects (or grounded if YOU are ungrounded) hundreds of meters away.
He also powered bulbs at distance and set alight generator in powerplant wich tells how much power had to be wasted to do tihs.

His topload was on pole very high above his laboratory, probably to lower its capacitance to earth as much as possible (for higher resonant frequency) and still have large surface to couple capacitively with things around.
MT generated about 4 milion volts but streamers were suppresed (as they would be a waste of power).

TC are still horribly inefficient devices, and power is expensive so that never found a practical use.

There is a lot of PS bobbled about tesla mostly because lack of knowledge in the crowd, even wikipedia shows something unclearly about some schumann resonanceson the earth itself, but I dont see how is it linked to anything and how can it make magnifier more efficient

Nor that with horses doesnt seem to be true, since horse is always 'earthed' (unless it jumps around topload

) and many other stories just have no proofs.

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