Contributed by AJ5W (David)
With all apologies to the ham-centric podcast 100 Watts and a Wire (which is a fun show if you’ve never tuned in), the FSK mode WSPR can provide results with far less power. WSPR was developed by Nobel-winning physicist Joe Taylor, K1JT, to study propagation. I occasionally set up my software-defined radio to run WSPR since it can largely be left unattended. This past weekend, I set up the SDR to run WSPR with one watt of output on 40 meters. My “beacon” was set up to transmit 20 percent of the time and listen for other stations during the remainder of the operation. The total operational time for this test was a twenty-hour period from Saturday evening through Sunday afternoon (some operators let WSPR run uninterrupted for days or weeks at a time). Oh, and the antenna – a shortened, end-fed resonant dipole…in the attic. Less than ideal is a pretty big understatement.
Unsurprisingly, my one watt signal on 40 meters was robustly received across the contiguous United States and southern Canada. Now for the WOW factor. There were two reception reports from stations in Australia (see screenshot). The station in southwestern Australia, VK6XT, is nearly 11,000 miles from Tulsa – on ONE watt! Not only did he hear me, but I heard him as well. Even though this was a passive “contact,” it demonstrated that DX – extreme DX – is possible with low power and a modest antenna. In theory, a bona-fide two-way QSO was possible since we each heard one another’s station. Not bad for one watt and a wire strung through my attic.
If you are looking for a new challenge in the world of digital HF, give WSPR a try.
Wednesday, March 9, 2016
The next Tulsa Digital Radio Club meeting will be Saturday, March 12th at 1 PM. It will be held at the Broken Arrow Central Library at 300 W. Broadway.
We will cover "RMS Express message addressing". The Tulsa system is now linked via HF, VHF, and internet to the N5CST system in Poteau, OK and the KC5OAS system in Magnolia, AR. We also have a full-time internet connection to the Branson, MO N0KFQ system. We will show you how to address messages to recipients on the other systems.
As always, we can answer general questions you may have regarding digital modes from packet all the way up to FLDIGI (PSK31, Olivia 8-500, etc.) and everything in between.
Speaking of Winmor, the AE5ME-12 system is now full time on 7100 kHz and 3595 kHz. We also have a 'weak signal" experimental Winmor port on 144.23 Mhz USB that has allowed an operator in West Tulsa county to connect using 2 watts.
Also, don't forget to check in to the statewide APRS net this weekend, which coincides with the start of the meeting at 1 PM. We will be operating the net from the library.
Hope to see you at the meeting!