Litzendraht wrote:
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

Hello John
first of all to share my happiness ,my bc624 is at home ,it took just a
week to come from Honolulu to France .This fact itself is
marvelous!!!It is in perfect good condition.It is marvelous to see 60
years old radio-set in such a nice condition ,it is nearly complete
,only the front panel mechanic to select channels ,has been removed .As
a begining I plan to use simple 2m yagi ,I have three of then 'tailored'
on 150 mhz that is an official band of radio-astronomy (shared with
other services ).In the beginning of radio-astronomy after several test
on microwave (around 3ghz) ,G.Reber finally used 169mhz ,a frequency
that is still in use in radio-astronomy
in several observatories .Here I have been using that frequency with
modified vhf radio-reciver (just cut one turn out of the input coils
,and tune again ,and tv antennas are ok)alas now there is lot of qrm by
vhf relais ,it is a local problem .I'll keep you informed .
You are right about the tubes ,I also have a gdo of that kind ,and
several acorn tubes .Thanks ,good bye 73 alain f1gqb