Hello Renato,
Hi!
I have a selective voltmeter Wandel & Goltermann TFH-2.
I tried to listen our 136 khz qso but I was not able to listen (i have a
multiturn loop homemade, 1 m. diameter, tuned via a variable capacitor. The
signal >is amplified by a cascode bi-Fet)
I think my selective voltmeter is too little sensitive (it is able to
measure -40 to + 40 dB).
I think it is possible to modify it!
Have you modified it?
Can you help me?
or must I put it in in the garbage :-(((( ?
Thanks and best regards
Renato IK2WYS
you are right, - 40 dB, is not sensitive enough (if it is -40 dBm, this is
equivalent to about 2 mV sensitivity, what you need would be at least about
-110 dBm. You might be able to increase the sensitivity with a
pre-amplifier.
However, don't through it away, those selective voltmeter do an excellent
job to measure the near-field of a transmitting station, and for that
purpose the sensitivity should be ok! Anyhow, don't through it away,
whatever you do ... those old instruments have a lot of components that
might be usable for LF applications ...
Vy 73
Geri, DK8KW (W1KW)
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