In article ,
says...
(Fred McKenzie) wrote in message
Keeping the oscillator running and keying subsequent stages will usually
produce a more stable signal. However, it is not unusual for some of the
oscillator's signal to leak through and be radiated by the antenna. You can
probably imagine a CW tone that gets louder when keyed, but the pitch doesn't
change. When such a station is nearby, it is hard to discriminate between the
strength of the keyed and unkeyed signal. If you use this approach, you should
pay attention to keeping the oscillator from bleeding through. One method
might be to key all of the following stages, for example.

I had a rig in which I kept the oscillator running on key up. "VXO 6 watter"
from "QRP Classics". Great rig. The "backwave" never caused difficulty in
copying. I got about 5 W out (keydown) and about 15 milliwatts out (keyup!)
This provided some fun: If a station gave me a good report, I'd ask if they
could hear the REALLY QRP oscillator on key up. Many could!
73 Bill CU2JL
http://planeta.clix.pt/n2cqr

was there any shielding around the VXO or a terminator to keep the
leakage down?

mike c