When talking about radio hacks, one may inevitably refer to WSPR (Weak Signal Propagation Mode) that’s often utilized to research the propagation conditions throughout the planet. It’s a fairly simple concept – a transceiver is connected to a WSPR client program (for instance, the one built into WSJT-X) that will listen to FSK-modulated signals. These signals are transmitted by other stations. Hence, the low-bit-rate signals will encode a minimal message into a digital signal. It will take about 2 minutes to send it. The decoded message will then be decoded to a central WSPR database. This one records any contacts and displays a map that describes the road between those stations. Learn all about it withVHF band.
There’s more than one way to go about it. You can use GPIO pins on a Raspberry Pi. This will allow you to generate the RF signal directly. However, in this case, you will need to find other hams on a ham radio forum and follow their lead using Si5351 clock generator breakout board and an Arduino Nano. Thing is – this clock generator board comes with a three-channel PLL-controlled oscillator which makes it easy to integrate into just about any kind of band in the first place.
With that said, I wanted to get my WSPR beacon for the 20-meter band. There was no other reason than the fact that I had success making WSPR contacts on that band, at least throughout daylight hours. For my first such project, I had to strip out all the whistles and bells (these are very easy to add to an Arduino project). Since WSPR transmissions need to be thoroughly synchronized in order to begin at the very top pf every even-numbered minute, it’s no wonder that most of those projects come with elaborations such as a GPS receiver or an NTP client that are designed specifically to help you handle the timing. Well, in my case, I decided that it would be far less complicated to just lay my eyes on the clock and press the button to being the WSPR transmission cycle at the right moment.
There is a slight problem still. However, I do know that my signal is encoded properly and I fit the frequency, so the issue may lie in the antenna I am using. Or maybe it’s the low-power signal. Anyway, I ordered some additional parts, so I’ll check the new installment to see if it will work the way I need it to.