WSPR Desktop Transmitter in Tanzania
Updated: Oct 5, 2019
One of the WSPR Desktop transmitters have found its way to East Africa running continuously as a WSPR beacon in Tanzania.
André OE8ASR/5H7MP is the operator. He contacted me in May about the possibility of getting a WSPR Desktop customized for 40,30,17,12m. I agreed and sent it to him early this summer. He had some problems and false starts so we stayed in contact while I helped out best I could over Email. He mentioned he would take it to a remote location so it was important it would work well standalone. He has up till now operated the transmitter out of Austria and tweaked it in preparation for the remote setup. Everything seemed to be working fine and this week he moved to the remote location in Tanzania. While he was on site there was one final problem that I had to fix for him and that was a bug in my PC Software that stopped him from saving a custom TX Delay.
There was a bit of a time emergency as we had to fix this problem before he left for Austria again. Luckily I was able to find the bug and rewrite and compile a new version for him, that is the 0.78 version that is available now in the download section.
He wanted to have a TX delay around 1000 (16 minutes) as his power source is solar cells and batteries and the power budget might not be large enough for continuous operations.
The Beacon is running with the following power levels:
40m - 1 Watt
30m - 1.5Watt
17m - 2 Watt
12m - 0.1Watt
Andre was kind enough to send me some pictures from the site.
I checked the results for the first week of operation and it seems to be performing really well.
Andre even managed to get a number of spots from Hawaii which is more or less on the other side of the planet from Tanzania. According to my calculation the earth circumference around the equator is 40,000km so that would mean the long path would be 21,300km and the short 18,300 as shown in the screen shoot. One might guess that the signal picked up in Hawaii was the long path as it goes over water most of the distance but there is no way to know for sure.
The Antenna is an off center feed dipole with a 100ohm resistor across the feed point to help lower the SWR. Here is a VNA scan Andre sent me, The SWR is especially low on 10MHz and it can be clearly seen in his spot list that this band is performing very well for him.
SWR Plot 1-30MHz
The antenna is only 10.5m long and with a resistor over the feed point one would expect such an antenna to not be a very good transmit antenna but the proof is in the pudding as the saying goes.
Also notable is the great performance on 18MHz. I suspect the near equator location helps out with that as I have noticed that while the MUF rarely goes up to 18MHz here in my northern latitude in Sweden - in places nearer to the equator it does more often go up to 18MHz and beyond. There was also the odd spot on 12m in Europe that might confirm that theory further.
All in all this will be a great beacon to check out the the propagation on 17m and 12m as the sun is getting more active in the coming years.
Andre also operate a normal station from this location.
Well done André and thank you for sharing with us.