Re: LO off QRG


igor-m <mikki@...>
 

Steve, when you change the tuning voltage wired to the VCTCXO the TX frequency (measured with a counter at the dummy load) has to change too, imho. The 7000's firmware or hardware has not got any internal means how to determine "how much the frequency of the xtal has changed by applying certain voltage difference". There is none internal reference except the master VCTCXO oscillator.
Thus, when your external counter show 21.000.000 at the TX dummy load with "5F" hex, and you change it to "2C" you must see a change of the TX frequency after returning from the manufacturing menu. The important assumption is there is the "VC" TXCO module soldered on the board, the DAC works and the firmware has not got a bug as well.
Would be great if we will come to an understanding "how the stuff works", as this is a topic people here discussing for a decade already :)

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