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Old March 22nd 09, 03:52 PM posted to rec.radio.amateur.homebrew
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Default Was my father's homebrew double conversion SW receiver a HBR?


"Joerg" wrote in message
Yeah, I wish the designers of the NRD-515 here had known that as well.
Every few months a relay will become "sticky". The S-meter drops to zilch,
rock the attenuator switch 5-10 times, and it's back :-(

Relays with some current are ok but I prefer the electronic method. PIN
diodes with lots of current and plenty of carrier lifetime usually work.
One just has to make sure there aren't any rectification effects that can
cause IM or harmonics in the presence of strong signals. FET switches are
sometimes a good deal as well but since the SD5000 and SD5400 have gone
towards high-priced boutique status not so much anymore.

--
73, Joerg


Hello Joerg

Odd you're having that problem with the NRD-515. So far mine
has been rock solid, except for the rotting foam disease in the
mechanical filters... But... I do have constant problems with
the relay that selects the external VFO in the NSD-515
transmitter! It always needs attention and cleaning. Its the
odd-ball relay that was added on the bottom of the mother
board. I'm wondering if you have had the same problem
with the transmitter (assuming you own the pair) and what
you did to fix it.

73

Peter k1zjh


 
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