27 December 2021

Signal source for 24 GHz

UV-82 400 to 520
UV-82 400 to 520 MHz
While waiting to go outside with the 24 GHz experimental setup I tried to measure the module frequency. The simplest way to generate a 24 GHz signal of known frequency is to multiply a UHF source through a diode.

That's nothing new, it's cheap and worth trying. So I rigged up the multiplier shown in the picture with an unknown Schottky diode.

The Baofeng UV-82 RTX transmits between 400 and 521 MHz; that's plenty of choice to get an harmonic show up in the GHz range.

In order to check if it works I first looked for the harmonic on 10 GHz through an LNB, and sure it was where expected.

Unfortunately I did not see (receive) anything on 24 GHz, even at the higher power setting of the UV-82 source.

A better view of the diode and adapters.

Then I tried with a source that covers 2000 to 2990 MHz and there was no sign on 24 GHz while it was very strong on 10 GHz. I think the LNB amplification chain makes a lot of difference.

Still a 24 GHz module can receive another module at 12 metres distance with S9 and probably more once the antennas are properly aligned. I postpone the frequency measurement and spend time on checking which distance is possible in a radar-to-radar setup.