Well, I did the tests and am reporting back. We can argue about it later
1. BU225s were worse than BUX80s (i.e. more noise)
2. They wiped out the medium wave (560 -1600khz) and did not have the
more limited effect of the BUX80s which notched out local stations and
then just annoyed on the rest of the waveband
2. Moving mains point did not solve the problem. It reduced it.
3. Moving to Battery power more or less did solve it. The radio became
quite understandable, with noisy patches when the ferrite rod in the
radio was end on to the interferance. So it was directional.
This seems to confirm
a. That transistor equivelants were a bad idea
b. That the majority of the noise is coming through the mains.
c. That a mains filter might have been a good idea after all.
/knocks himself on the head
BTW, These diodes are a mains full wave rectifier, but have NO
electrolytic smoothing it. That's pretty unusual on a single phase.
That's where I'll start. I know, I know, electrolytics are useless at
hf, but it might keep the voltage up across those diodes.
--
With best Regards,
Declan Moriarty.
--
Author: Declan Moriarty
INET: [EMAIL PROTECTED]
Fat City Hosting, San Diego, California -- http://www.fatcity.com
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