In article ,
amdx wrote:

Thanks Graeme,
I'm thinking about building the mixer that was in QST Feb., 1993, an
article by
Jacob Makhinson. Titled, "A High-Dynamic-Range MF/HF Receiver Front End"
The mixer uses a quad FET IC, (Si8901 from Calolgic corp.)
The only online reference that I can find is here; See pdf pages 26 (text)
27 (schematic)
http://files.bluecrow.net/Amateur%20...ok_2007/11.pdf

Google around for "H-mode mixer" and "Tayloe mixer" if you want more
information. http://www.webalice.it/romano.cartoc...mode_links.htm
will get you started with *many* links to investigate.

There has been a lot of interest in this sort of switching mixer
topology in recent years... quite a few articles in QEX for example.
Many designs have come out, some of which are based on general-
purpose multi-FET parts such as you suggest, and others which are
based on CMOS "fast bus switching" ICs, such as the FST3125 and
similar. This seems to be a very good topology for handing signals
having a very wide dynamic range... I believe that Elecraft uses a
design of this sort in their K3 transceiver.

The front end is designed in three modules, preamp, mixer, and post amp.
Anyway I'm thinking about building the mixer and playing with it in the
AMBCB.
Even thoughts about building an I/Q receiver.

Yeah, I've been toying with that sort of idea too... making a
"binaural" direct-conversion receiver. There was a binaural design
published in QST a year or so ago, which uses the NE602 or similar
Gilbert-cell mixers... building one which uses H-mode switching mixers
and a couple of low-noise audio amplifying chains could be fun.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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