At 2/9/2005 09:35 PM, you wrote:
>I have a Circa 1982 Mini Circuits mixer, ZXM-2 but it seems it is not
>made anymore as MCL denies all knowledge of its existince. I was
>wondering if anyone had the spec sheet for it? It has three BNC
>connectors on in, "R" "I" "L" and is about 2" X 3/4".
> I was hoping I could run a 1GHz LO into it to hetrodyne a cable
> modulator to 1277.25 for my up and coming ATV repeater project.
My '91/'92 Mini Circuits catalog doesn't list it either. However, looking
at their numbering scheme for their other mixers suggests that it's a
5-1000 or 10-1000 MHz unit.
Yes you can use them as up-converters. However, your conversion loss will
be higher since your output signal will be above the upper limit of the mixer.
Start driving the LO port with 0 dBm @ 1 GHz & slowly increase the LO drive
until you see diminishing increases in desired output. It's probably wants
+7, +10 or +13 dBm of LO. And of course make sure you filter out the
722.75 MHz that will also be coming out of the RF port of the mixer (1 GHz
into LO port, 277.25 MHz into IF port), as you'll be getting more power
there than at 1277.25. Also make sure that your 277.25 signal is at least
20 dB down from your LO drive level, otherwise your video signal will
intermodulate with itself within the mixer, generating all kinds of crap
throughout the 1.2 GHz band. This means you won't get more than around -20
dBm of 1.2 GHz signal out of the mixer, assuming it works OK at 1.2 GHz.
Bob NO6B
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