From Wikipedia, the free encyclopedia.
WSPR (pronounced “whisper”) is an acronym for Weak Signal Propagation Reporter. It is a protocol, implemented in a computer program, used for weak-signal radio communication between amateur radio operators. The protocol was designed, and a program written initially, by Joe Taylor, K1JT. The software code is now open source and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF bands.
W8UM Receiving Station Link: Map | WSPRnet
Enter W8UM into the “Receiver Call”
WSPR Beacon on 10 Meters
In collaboration with The Case Amateur Radio Club of Case Western Reserve University, W8EDU, (see their side of the story here), students at the University of Michigan Amateur Radio Club assembled a raspberry pi + LPF WSPR beacon to be used on 10m. This setup transmits ~10dBm (10mW) through 3 RF switches, a few hundred feet of coax, and through a 10-40m trapped vertical antenna.
Transmissions were successfully reported by multiple stations at wsprnet.org on bands between 80m and 15m. Transmissions on 10m from W8UM to W8EDU have been unsuccessful so far, having tried the 10mW from the raspberry pi, as well as short-duration transmissions using 5W, 10W, and eventually 20W from the Kenwood. The high power transmission station has been shut off, but continues to operate in receive-only mode.
W8UM has been able to hear W8EDU’s transmissions on 10m, using a SteppIR HF yagi antenna pointed at heading 116 degrees from north. Initial results are presented in the graph below:
It was observed that the raspberry pi transmitting WSPR idles on the frequency previously transmitted on, even after the transmission ends. This causes causing local interference that desensitizes our simultaneous signal reception. With the Raspberry pi rotating between 40m, 10m, 10m, 20m (in order), while the Kenwood alternates on TX, RX, TX, RX on 10m, we get alternating points of high and low signal levels that make the resulting data unusable.