WSPR How low can you go? (And still be heard)
As part of my Flying Squirrel project, I wanted to know, “Would my little Si3551A based telemetry transmitter,sending WSPR, ever be heard by anyone?” So I conducted the following test.
- I configured the Radio gear to send the absolute minimum signal possible, on the 20m WSPR frequency:
- A picture of the WSPR software transmitting at 20:40 UTC. 1:40PM Pacific
3. And finally WSPRNet.org confirming reception by two monitors.
The total power out of the radio is just a few milliwatts and I am being heard across the US continent! (I live on the West coast in the Greater LA area). I should add that my coax run, is about 150ft of coax, so even less power is reaching the HF vertical antenna in my yard.
I left the experiment running for a while and almost every transmission cycle on WSPR, had at least one station hearing my station. WSPR has an amazing ability to pull signals out of the noise. In the case above I was heard at -23db and -25db.
This is good evidence my SI5351A will be heard!
73s de KJ6FO