First WSPR spots on 630m

A few of my blogging colleagues have written about having surprising success WSPRing with modest antennas on the 474kHz VLF band. I thought I would try to see what if anything I could spot using my attic dipole as an antenna.

Receiving WSPR-15 on the 630m band

I downloaded the WSPR-X software which supports the new WSPR-15 mode. (The standard WSPR for HF and VHF is now called WSPR-2, the number indicating the duration in minutes of the transmit cycle.)

First problem was to find a receiver that would tune to 474kHz. My K3 would not tune below 490kHz nor the KX3. My K2 doesn't have general coverage at all. My SDR-4 receiver would not go anywhere near the frequency. My FT-817 came to the rescue. I took it out of the drawer, blew the dust off it, found a power lead, switched it on and it tuned to 474.2kHz quite nicely.

The next problem was to find a sound card to receive the audio. I have three USB sound devices currently connected to the shack PC and I could only identify which driver was for which sound card by trial and error. After I realized that WSPR-X can be used for HF WSPR as well I tried it out first on 30m. For about an hour I had confusion as I did not seem to be receiving any WSPR signals at all. Eventually I tried WSPR-X on the sound card used by my K3. Once I verified that the program worked and was decoding spots I then tried receiving 30m WSPR on the '817. Once that was successful I tuned the receiver to 474.20kHz, set the mode to WSPR-15 and left it for a few hours to see what would happen.

I was doubtful whether I would receive anything on my 80 - 6m multiband dipole which is too short and totally unmatched on the 630m band, but when I came up to the shack later this evening I saw there were three spots of PA0A in JO33 at 30 minute intervals! These spots were not reported to WSPRnet as I had been so pessimistic of my chances of decoding anything that I hadn't bothered to tick the "Upload spots" check box.

So the experiment was a success. I doubt that I will receive anyone else on this antenna so it is probably not worth leaving the radio set up for it but it was fun to see what can be received here on this new amateur band.

Receiving SAQ on VLF

Roger G3XBM has posted a reminder in his blog that the Swedish station SAQ will be making a special Morse transmission today on 17.2KHz VLF to celebrate the 100th anniversary of the Nobel Prize award to Guglielmo Marconi and Karl Ferdinand Braun.

As 17.2KHz is in the audio spectrum it should be possible to receive this transmission with nothing more than a computer sound card. And Johan SM6LKM has written a software defined radio (SDR) program that will do just that. All you have to do is download the program from his web page, unzip it to a suitable folder (it's tiny, and there is no installer) and run it.

You need to connect an antenna to the left channel of the sound card microphone input (the program uses the Windows default sound card.) I don't have a long wire or any other VLF antenna so I have just used the outer (screen) of the feeder to my attic multiband dipole. Check that you have enabled the microphone input and increase the volume slider to maximum. The program will tell you if the input level is too high. You should see signals appear that disappear when you disconnect the antenna.

You can then increase the output gain in the program itself until you can hear the background noise. I can hear a few warbly carriers near the top part of the spectrum, as you can see in the screenshot above, and the occasional burst of static, so I'm definitely receiving something off-air and not just locally generated noise. There's a button that will set the correct frequency for the SAQ transmission.

It's too late for the transmission that was sent at 0800UTC today, but another is scheduled for 1600UTC. I have no idea if it will be possible to receive it with such a simple setup and poor antenna but it will be fun to try. If you read this too late for that, then there will be another transmission at 0800UTC on Christmas Eve, December 24th. I'd be interested to hear if anyone manages to receive it using this program, and with what antenna.