Wednesday, February 3, 2016

Arduino UNO, SI5351A breakout as 902MHz CW beacon

Today I decided to try to get this little beacon project up to 902 MHz, lo-and-behold it works. :-)

During the test I had forgotten I had two 15db pads (total of 30db) on the IF going into the mixer.  Since the signal was so weak with that, on the RF output side, I added a 0-500 MHz 1.5W RF amp before the final Frequency Doubler.  Which worked.

However, after this video I removed the 30db of attenuation, and the RF amp, and it was quite strong.  

Still this is a decent demo.

I also show how the almost raunchy 25 MHz TCXO.  I hate TCXO's.  My plan is to remove it, and use a 25 MHz GPSDO and that issue will be gone.  NOBODY likes a drifty beacon.

While it adds expense to the project, it's something I can test with a GPSDO I have on hand...once I've verified it resolves the problem, I'll order another (since I already use my current GPSDO in other projects).

Anyway here's the video of today's 902 MHz Beacon test.