After experimenting with QRSS on 136 kHz about 20 years ago, I started playing with QRSS on HF in 2024. There is an active community called the QRSS Knights on groups.io.
I am using a Raspberry Pi 4 as the transmitter, using my own version of the "WsprryPi" software, modified to transmit QRSS CW and/or FSK-CW. Find the sources for my WsprryPi + QRSS clone here. This software produces a QRSS signal without any external hardware; it's directly available from one of the GPIO pins of the Raspberry Pi. Of course, some filtering of the signal is required before connecting it to an antenna. The approximate output power is in the order of 10 mW.
Most of the time I am transmitting FSK-CW6 on about 10139.850 MHz (the transmission takes about 7 minutes), followed by a single WSPR transmission in the 8th minute, triggered by appropriate Cron-Jobs. The transmissions are never unattended.
Since I have no permanent antennas at home, I installed a grabber at SO5CW in July 2024.
Details of the grabber setup can be found on a separate page: QCX + Raspberry Pi QRSS grabber and WSPR receiver setup.
It consists of a QCX and QrssPiG running on a Raspberry Pi connected to a simple vertical antenna. Click the picture below to enlarge the current grab, or check out QRSS Plus for the grabs of the last 8 hours.
An archive of the last week's grabs is available, as well as a 24h view with clickable links to the corresponding 10 minute frame. The 24h view also features a plot of the Solar flux.
In addition to QrssPiG, the RaspberryPi also runs k9an-wsprd (with some scripts and modifications by DJ0ABR, DK2RO, VK3TPM, etc.) which uploads all spots to WSPRnet.
You can see the latest spots generated by SO5CW on WSPR from wspr.live in the table below:
A few screen shots of my own signal being seen on grabbers, thanks to QRSS Plus by Scott Harden (AJ4VD) and Andy (G0FTD).
On 10m, the frequency stability of the Raspberry Pi is not very good...
My first capture ever, in QRSS mode (lowest trace).
Last modified: Monday, 28-Jul-2025 08:23:56 CEST