UHF mixer

Hi friends,

I need UHF mixer schematic for downconverting ~450MHz to ~45MHz.
This is a receiver project.

Ther are a lot of docs. on the web about mixers. But I can't use any special IC . I have to use only a few transistor for "mixer" section.

There are some simple ways using transmission line sections and diodes. You can also use double balanced mixers which have transformers and diodes.

Try a web search for amateur projects. The amateur radio handbooks put out by the RSGB and ARRL should have some examples. They also put out microwave project handbooks.