G0JJI > 31-07-2017, 01:05 AM
VK3ALB > 31-07-2017, 09:09 AM
VK3YCQ > 31-07-2017, 12:20 PM
G0JJI > 31-07-2017, 06:14 PM
(31-07-2017, 09:09 AM)VK3ALB Wrote: Hi Peter,
I think you can trust Drew's work. Can you hear the VFO and BFO using another receiver? Can you inject a signal into pin 1 on either NE602 and see a corresponding signal at the output?
I don't have notes on the NE602 but are those readings in keeping with expected input for the device?
(31-07-2017, 12:20 PM)VK3YCQ Wrote: gDay Peter,
without being familiar with the exact circuitry, my immediate response is the same as Lou's. Check to see if the oscillators are oscillating. It is a good sign that you are hearing broadband noise... at least some RF energy is getting through! If you can detect output voltage from the oscillator using the RF probe and yet still cannot tune in local signals, this implies that the frequency is wrong.
regards
Ian
VK3YCQ
VK3ALB > 31-07-2017, 11:20 PM
G0JJI > 02-08-2017, 07:29 AM
(31-07-2017, 11:20 PM)VK3ALB Wrote: Hi Peter,Hi Lou
Once you've found the VFO and/or BFO you should be able to loose couple a signal from a TX (a wire hanging near a dummy load) to the antenna input then search for a signal with your RX at the output of the 1st NE602. Once you have that repeat the process for the remaining stages.
Yes it would be nice to use a sig gen and a 'scope to see what is going on. Is your colleague or a local ham club in a position to assist you?