GRES joins the Global Flea-Powered Digital Whisper

RADIO CONTACTS CONFIRMED OVER 17,000 KM DISTANT ON JUST 0.2 WATTS

WSPR demonstration

On Tuesday 14-11-23 at the GRES club meeting at South Barwon Community Centre, an experiment was held testing the performance of home-assembled WSPR equipment.

The “Weak Signal Propagation Reporter” system uses an extremely low-power transmitter, sending an automatic digital coded signal containing little more than callsign, grid locator and power level data, all compressed into a 50-bit signal, sent very slowly at a bandwidth of 6 Hz and taking about 110 seconds. The system was designed to test propagation paths on LF, MF and HF bands. (Ref. www.wikipedia.org/WSPR)

A live on-line database at www.wspr.rocks can display signal reception activity, including as a world map.

Our evening’s experiment used a tiny WSPR transmitter (from www.zachtek.com) with an end-fed half-wave antenna (loaded with a “No-Tune” board from www.qrpguys.com) and a calibrated 8.74m length of hook-up wire supported at the top by a 9m telescopic squid pole (from www.haverford.com.au).

The transmitter was programmed to operate on 20 metres (14.1 MHz) and set up in the car park outside our Belmont meeting room. Transmission was measured on a power meter displaying that its output was just 200 milliwatts (see photos). The antenna was set firstly on a north-south orientation, and later east-west to compare reception results, which were monitored in real-time on a computer indoors.

All those present at the time were very interested to see that these signals had been immediately detected around the world, including Japan, New Zealand, Alaska, eastern USA and Canary Islands! – see screenshot.