Total posts : 45366
In one of my earlier Part 15 AM transmitter
setups, I used a homemade variometer.
The outside coil was wound on a bucket from the
hardware store – I don’t remember the
dimensions, but it wasn’t that big.
The inside rotatable coil was wound on a round
plastic margarine container.
It worked. I had some kind of plastic rod that
went through holes on the outside coil form,
which was attached to the inside coil form.
It was a very long rod, so you could turn it
and be pretty far away from the variometer.
You could hold one of those cheap CB/ham radio
field strength meters in your hand and peak it
up just by looking at the meter.
The set-up tuned over a small range. It took
a long time to set it up and get it running, but
it was worth it.
At that time, the AM transmitter was a fixed
up Ramsey AM-1, which was also modified for
crystal control. That set-up didn’t go as far as
my SS-Tran set-up, but it did work well. I think
it got out 1/2 to 3/4 of a mile. When I say the
AM-1 was fixed up, I just mean that a friend of
mine put some better caps into the transmitter,
because it had some stability problems.
It was a lot of fun putting that set-up together.
It was my first set-up that actually went some
Bruce, Dog Radio Studio 2
P.S. The 1700 kHz transmission from the
AM-1/variometer set up also came in real
well on my Heathkit CR-1 crystal radio.
Actually, it blew it away!