Well, each band model has its own crystal local oscillator. The chance of their all being off 100 Hz is zero. The PTO can be off, there is a cal process for this - it would affect all bands the same
Do you get high SWR on 12 meters? Is the ALC light on when the transmitter goes into power limit? If so, one of the relays on the LPF board may be defective. This would result in high SWR so the ALC
I did not see the part about the low RX, sorry Possibly the 12 meter crystal oscillator switching diode is bad (D14) or the coil (L21) is open. More likely, the solder joints around these two compone
I did not see the part about the low RX, sorry. Possibly the 12 meter crystal oscillator switching diode is bad (D14) or the coil (L21) is open. More likely, the solder joints around these two compon
The use of dual diodes is likely an attempt to improve isolation at this point and also to allow use of that transistor to pull the signal point to ground, thereby improving attenuation here. Are you
Thank you Phil for reaffirming the concept that got me ejected from the Collins Folklore reflector. Drift of circuit alignment NEVER causes 20 dB changes in performance, unless mis-alignment causes a
More likely than alignment as an issue, would be the switching diodes for 12 meters, or, again, bad soldering of the circuitry around those diodes and associated coils. You can check the continuity o
When diodes such as PIN diodes are placed in series, the signal isolation improves in the off state but makes little difference in on state signal loss. Gary
The only boards with band sensitive components are the bandpass filter 8056, the low pass filter 80561 and the crystal oscillator board 80563. On 80561, the same tuned elements are shared between 12