[Yaesu] 3SK51 Mixer problem

[Jon Klinkhamer]

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?

Thanks,
Jon
KB1DC