Saturday, January 30, 2010

Rock-Mite 80, update

The oscillator coupling is now done by 7.5pF. Additionally, a 10V Zener diode stabilises the varicap voltage. The latter step made the TX frequency to drop to 3579580Hz, according to PA9QV's grabber. Looks a little bit more stable now, and does not show this funky power up behavior...

In a further firmware mod, the TX QRG is switched to just before transmission so that the grabber is now QSK w/o that funky frequency shift. My impression is, that there is no impact on the stability of the signal.

Test on QSK, the strong carrier at '750Hz is the Ramsey, the 50Hz lines belong to it too (presently) for comparison, a view from my neighbor's grabber (Jan, you got a TV in your area too).