Re: prog rock ge mastr exec ii

Robin Midgett
 

Bob,
The low pass filter kits from QRPLabs are very effective for making sine waves from the square wave outputs of the ProgRock.
Thanks,
Robin Midgett K4IDC


On Fri, Jul 5, 2019 at 1:18 PM Bob / WA1MIK <wa1mik@...> wrote:
I'm working on a similar project, but in my case it's an old Motorola Compa-Station (Motrac-based) on 10m and it uses phase modulation after the crystal, so a ProgRock should be a good substitute for a signal in the 7-10 MHz range. This station uses channel elements. I plan on removing the crystals and feeding the ProgRock into the channel element, using it as a buffer stage. I may need more gain and possibly some filtering to turn the square waves into something more sinusoidal (crystal-like).

I plan on using bank switching by connecting the active-low PTT signal in the station (through a diode) to the Bank Select 0 input. That way I can have just one output active at a time, or at least disable the TX output from the ProgRock.

I initially installed the supplied crystal just to make sure the ProgRock worked. I then installed the Fox 27 MHz TCXO and after adjusting the reference register, I got its 10 MHz output to within 1 Hz. I plan on installing the ProgRock into a small aluminum box and stuffing it with pink fiberglass insulation. In my case, a drift of a few Hz at 10 MHz will only result in a drift of maybe 10 Hz at 30 MHz, and that's definitely close enough for me.

Bob M.

Join QRPLabs@groups.io to automatically receive all group messages.