07 April 2009

WSPR: Beginner's Luck?

I had to confirm my MP3 WSPR assumptions with an on-the-air test. With the family permission I erected the antenna (base loaded horizontal monopole on the balcony), plugged the MP3 pen to the FT-817 and pressed the "Play" button at the +/- correct moment. No GPS or any real-time clock sync method was involved.

Output power was in the 0.5W ballpark, perhaps less since I was careful not to overdrive the FT817 SSB circuitry (50% ALC). FT817 uses ALC to control output power, so I need to measure it (another day, please).

On the wsprnet.org website, where WSPR spots are uploaded in real time by some kind listeners, my call appeared at 4 macro-distances: 8, 1000, 2000 and 19000 km away. 19000 km means New Zealand, The Antipodes from here.

What's Next? Either setup a WSPR Moon receiver or build an independent DSB/SSB transmitter.

One thing to mention. In this experiment I ran a 100% TX and 0% RX. I transmitted for 2 hours without breaks, except for few seconds between each sequence. This can be relaxed adding 2 minutes (02'00.00") of silence in the WSPR audio file.






Call Frequency
Drift Grid dBm
by loc km
mi

IK1ZYW 10.140117 -18 0 JN35tc +27 0.501 OH3QN KP20tx 2121 1318

IK1ZYW 10.140117 -21 0 JN35tc +27 0.501 M0DUO IO91kw 995 618

IK1ZYW 10.140130 -15 1 JN35tc +27 0.501 IK1JNS JN35sb 8 5

IK1ZYW 10.140127 -19 0 JN35tc +27 0.501 EB1APK IN73bg 1094 680

IK1ZYW 10.140168 -26 -2 JN35tc +27 0.501 ZL3IN RE66hk 18812 11689

IK1ZYW 10.140131 -24 0 JN35tc +27 0.501 G4KYA IO93ln 1129 702