nierveze wrote:
the 9003 input tube is the successor of the 955 acorn in an another 'box'.


Alain,
I was pleased that you mentioned the 9003 being the successor of an
acorn tube. I started to mention that when I said I replaced the 9003's
with 6AK5's. There was a series of 7 pin minatures that replicated some
of the acorns.

I think the 9003 was actually the replacement for a 954 pentode acorn
and the 9002 (also used in the BC 624) replaced a 955 triode.

My B&W grid dip meter that I've had for a hundred years uses a 955
oscillator. And I did some tinkering in those early days with portable
2 metre equipment with 957 battery triodes. One small transmitter I
built used a single 957 ultra-audion oscillator and I modulated it with
a Shure magnetic microphone in series with the grid resistor ground
return. Pretty simple circuit. It sounded great on the BC 624!

What type of antenna array do you plan to use? Do you know the
frequency range that was used in the early experiments that you
mentioned?

John