Does the radio wander up to this frequency and then sort of slowly stop wandering??
The local oscillator in this radio is simply the output of a VCO in the synthesizer, one that uses the analog PTO as a reference. That is how you get a PLL that can be varied by a simple analog PTO without need for producing a premix, such as was produced in the ¡°4 line¡± radios, and many others.
This local oscillator mixes with the incoming signal to be heterodyned to the first IF, 48.05 MHz. The DR7 simply counts this local oscillator signal, subtracts the IF frequency from the LO signal to produce the reading you see on the display.
There are two separate VCO¡¯s in the TR7 (and R7). One covers the low bands 0-15 MHz and the other covers the high bands 15 to 30 MHz.
Thus it appears that your high band VCO is not operating. Of course, cleaning the band switch nd the Molex connectors on the VCO board are your first things to do.
On Dec 25, 2024, at 11:44?AM, Jim Harris via groups.io <radiove1rb@...> wrote:
I now have the receiver and transmitter working good. The problem now is that the 15 and 10 meter bands do not work. The display shows the frequency in the photo. I am trying to find time to read how the frequencies are done. Anyone seen this before or have any suggestions where to look for the trouble? Thanks again for your help.?
