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Old December 21st 07, 07:22 PM posted to rec.radio.amateur.homebrew
Mike Andrews Mike Andrews is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 76
Default VHF/UHF (and above) to HF Downconverter pointers/ideas?

I've got an RFSpace, Inc. SDR-IQ Software Defined Radio, which is a
truly nifty gadget, but it stops at 30 MHz. I'd like to put together a
downconverter that I can drive with a DDS LO or my HP 8640B, to pull the
stuff above 30 MHz down into some part of the HF (or lower) spectrum. It
would be nice to be able to see a 190 KHz chunk of 6m or 2m or 70 cm., as
I can with the spectrum below 30 MHz.

At the moment, I'm looking at just plumbing together a MiniCircuits mixer
(probably +3dBm or so), some low-pass filtering, and maybe some front-end
gain so that I can be sure there's enough RF to drive the mixer.

Does anyone know of
COTS boxes to do this, or
designs in QEX or some other ham publication to do this, or
another ham who has done this or is working on it?

If someone here is doing or has done this, I'd love to know if I need a
gain block before the mixer. Other constructive comments will be welcome,
too.

73, de

--
Mike Andrews, W5EGO

Tired old sysadmin