Maker Pro
Maker Pro

That Notorious Field-Strength Meter: the pictures at long last


Paul Burridge

Jan 1, 1970
15 turns on a T50-2 toroid gives about 1.1 uH. That's probably close
enough and will take you a couple of minutes to make.

Oh, I had the dimensions and all that, thanks to Remarkable Reg's
"Solnoid2" (sic) program for working this type of thing out. On the
former I used I turned out to be 19 turns, but a ferrite slug knocked
that back to 16 and that's what I went with. Most of the problem was
in getting the bloody wire to stay on the former. I tried varnish,
superglue and model enamel before admitting defeat and taping the
bloody stuff in place, which of course looks shite. Finding suitable
enamel wire was another time-consuming pain in the arse! Then trying
to resonate the things with a known 1% capacitor against my grid dip
oscillator (which for some reason works brilliantly only on certain
frequencies and not of course the one I needed) which I had to give up
on and turned to a combination of signal generator, series resistor
and 'scope - a *vastly* easier way of seeing exactly where the
resonance was. So I'm *determined* to use those bloody coils! :)

Frithiof Andreas Jensen

Jan 1, 1970
Yeah, but it takes *time* to learn a new s/ware package and... oh,
bollocks. I guess there's no alternative. :-(

Learning about tools is time well spent....even if the actual project at
hand may not really justify it - other than to provide an excuse :)

I have been favoured by "luck" many, many times in my career: Studying
something out of personal interest, curiosity even, or perhaps for some pet
project on my own time .... and *then* people decides to use the very same
or a very similar tool/technique at work and I suddently happened to be "The
Expert (tm)" on it.