I just realized, I have a source with some power on 630 meters. My old Navy URM-25 signal generator, very stable and has an auxiliary input for audio. I'm listening to it now on my Yaesu FTdx3000 and its been on for about 40 minutes and has drifted about 5-10 cycles at the most, maybe less. When I turn the output all the way up, I can peg the "S" meter on the 3000 when I just touch a clip lead to the coax of my 80m dipole. I don't know the power output with this setup but I think it has possibilities Here's the rock solid signal on WSJT-X as received on my 3000 and the frequency counter.
URM-25 can produce max 2V into a 50 Ohm load = 80 milliwatts. Typical 630m antenna has about -10 dB gain, so this is around 8 mW e.r.p. Go for it!
8 mw would get some contacts runnning WSPR mode, but then I was thinking, I could use the URM as an exciter. But at the 100,000 uv output into 50 ohm, is enough to construct a transistor driver then a final amp for more power. BTW, the generator has been on since yesterday and it has drifted to 474.3-4.
The HP-200 series have more output on both the 2200-meter and 630-meter band and are pretty stable after a warm up. Glen, K9STH
I would leave it on 24/7 for stability. It may be more stable laying on its back. ??? Building a amp is easy enough. Have Fun.
Mike Murphy, WU2D, has been building a lowfer transmitter. Details can be found in Electric Radio magazine issues # 344-346. https://www.ermag.com/index/index.cfm?action=SelectIssue Phil