The TP114 test point should be a good place to get the frequency.? This is to prevent loading on the oscillator.? All I have got to go on is the schematic which isn¡¯t a very good copy.?
It¡¯s all I was able to find on the net.? Use an as accurate a frequency counter as you can get your hands on.? The cheap ones, unless they are GPS disciplined can get you close, maybe withing a 100Hz or so of the operating frequency.? GPS disciplined ones
can get you down to the Hertz level.
Have you checked the reference oscillator frequency?? It doesn¡¯t take much for this to put the entire system out of wack.? It¡¯s frequency should be 5.12MHz exactly. This is on the digital board. I have seen some synthesized radio¡¯s being
off quite a bit because the reference oscillator is out of adjustment, but this seem excessive.
Clint,
Havent done this yet but its next on my list. But a bit of confusion here. The RV75 manual Section 5-5.3 REFERENCE OSCILLATOR ADJUSTMENT calls for a freq of 1.280000 MHz AT tp114, while your guidance is 5.12 MHz. On the schematic it appears tha TP114 is after
a divider stage so this may account for the difference. I can see that this can create major problems if not set correctly. Thanks for the tip!
