06-05-2011, 11:15 PM
(06-05-2011, 05:58 PM)Wellington Wrote: Guys - many thanks for taking the time to respond!
Al. - the 'scope probe bore the details "10X 100MHz 13pF 10MΩ", the last figure being the impedance, I believe. It's unlikely that this could've stopped the oscillator, isn't it? I took up your suggestion and checked the voltage on the triode grid, with respect to cathode, using a DMM. The results were:
LW: ~ -10V
MW: ~ -5V
SW: -0.3V
That 'scope probe is fine.
The grid voltage on SW looks too low: all you have there is contact potential. Moreover, as you say, it doesn't vary over the tuning range: the oscillator isn't oscillating. The question now is: Why?
Your aerial is quite adequate for this set.
Al.
