Subject: 1st coils
Date: Wed, 11 Jun 1997 23:51:07 -0400
From: Jim <jwbuck-at-loclnet-dot-com>
I just subscribed to this list a few days ago. Actually I just got my
first true TC built yesterday. Anyway a few weeks ago I saw a picture
of a TC on the net. The primary looked just about like the insides of
one of my ham radio antenna tuners. I then looked around a little and
found a schematic. Well even the circuit looked similair to the tuner
so I took a few hours and wound a secondary on 18" of 1 1/2" PVC pipe.
I put a metal strip on the bottom and soldered the wire so I could
electrically connect the bottom of the secondary just by setting it in
the tuner. I connected a dummy load to the antenna terminal and
proceded to tune the tuner with the TC secondary installed. It worked
best at 3800 khz but even then only gave off 2" sparks with the radio at
full power (100W). I've had caps blow in my HF radio before after
about 10-15 minutes of transmitting a tuning signal while I walked
around and took antenna field strength measurments. Since I really
don't want to run the coil with the radio I built another coil in the
last few weeks complete with primary & HV caps. I am driving this new
coil with an old ignition coil connected to a 555 timer driving a SCR.
Anyway when I ran the smaller coil with the HF rig at 3800 khz the
sparks acted more like flames and I could touch them and not feel a bit
of a shock (although I did burn my fingers a few times). With the new
coil,running at a much lower frequency, the sparks are way different.
They are blue and shocked me when I touched one with a pair of pliers.
They also make noise where the first coil all I heard was the
modulating signal I fed into the radio.
Has anyone here built a high frequency driver for a TC? I'm trying to
figure out the best way to do it and I don't really want to have to
build a high power,100% duty cycle radio transmitter.