[Yaesu] Re: 3SK51 Mixer problem

[Al Fansome]

> I have a 22Mhz and a 50Mhz signal going into a
> balanced MOSFET, 3SK51. I'm
> expecting a 28Mhz signal output after a low pass pi
> filter. My problem is
> that the 22Mhz is always on the output according to
> my scope and freq
> counter. The circuit seems straight forward enough.
> I tried two different
> FETs with the same result. Is there anybody out
> there that can steer me in
> the right direction?

I could easily be wrong, but I thought the output of a
mixer is the original signals along with their sum and
difference products.  Thus you would need a bandpass
filter (instead of a low pass filter) to pass the
28MHz and reject the 22MHz.

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