RadioBanter - View Single Post - For Pete Gianakopolis - IC-R70 comments/question

Jake Brodsky · July 23rd 06, 07:12 PM posted to rec.radio.shortwave

wrote:
Now that I think of it Michael is correct. It was the 1N4007, the 1 kV
version of this slow diode that was recommended. It would tend to have
lower junction capacitance because of the wider depletion region due to
the heavier doping for the high voltage standoff. Once the diode is
biased on dc wise, the forward drop is not significant because it
doesn't "switch" with the signal current. I think the trend to
Schottky diodes was because of the lower intrinsic capacitance.

There are better switching diodes than the 1N4007, though they are more
expensive and less commonly available. It's not a bad switching diode
for RF if you don't have anything else handy. If I'm not mistaken,
Ulrich Rhode wrote an article in QST some years back about the use of
such diodes in high performance receiver designs. His opinion was that
although cheap, the 1N4007 didn't have a place in higher performance
designs.

DE AB3A