Earlier in the week I released my first boxed up product for sale here at ZachTek.com. It is a small fixed frequency receiver for shortwave reception of WSPR signals.
The very first customer was Bernard Ghiste - A Belgian Radio amateur with the call sign ON7AN.
He got the receiver three days after I posted it to him and he let me know it now was on the air listening to 20m.
When I checked what he was hearing on 20m I was presently surprised to see that he was receiving lots of stations. Se a snapshot of a 30 minute session below.
In fact he was hearing many more stations than I heard from my position here in Sweden and was even hearing stations in South America and Antarctica where I heard nothing.
Belgium and Sweden ar not were far away and considering we used the same type of receiver I was curious what the difference was so I reached out to him and asked about his antenna and location. He answered: "My configuration :Raspberry PI 2B, Raspian and .. of course WSJTx 1.9.0,
Antenna is W3DZZ home made and balun 1:1.
Situation : at the end of my garden with 40 meters of semi rigid TV cable (diameter +- 14 mm)High +- 12 meter,
Very quiet situation, the neighbours are at about 50 meters"
My Antenna is a dipole at about 10m height and I live in a small depression in the landscape so that probably accounted for some of the difference between what I was receiving and what he was at the same time but I think the biggest difference lies in his last remark.
"Very quiet situation"
Although I don't live in a city there still seems to be lots of man made noise at my position that probably raises my local noise level considerably. A few days later later that suspicion was confirmed when we had a total electrical blackout for more than 15 hours at my location. The whole peninsula where I live was without power and went dark and quiet. All around me in a radius of 15 to 25km all electrical equipment was silenced.
I took this as an opportunity to see what the HF reception would be on 20m using my WSPR-RX and a Laptop that had a few hours of battery in it. And sure enough, I started to see far away station after a short while, the furthest away was Argentina and Barbados. Se picture.
I also listened with head phones and a modified WSPR-RX that I could tune around the 20m band and boy was the noise level low! When I unplugged an re-plugged the antenna in to the receiver I did not get that usual very high noise that I'm used to get.
At quiet frequency spots that no one was occupying the noise was only increasing very slightly when I inserted the antenna, It was nearly magical and sort of spooky in it's quietness. But at occupied frequencies people were booming in.
This is is how it's suppose to be! I was thinking.
From these events I took away three points.
A good receiver, a good antenna and a good location is needed for maximizing your WSPR reception but sometimes you are limited by your local noise level.
It's fun to use WSPR to compare stuff. This time I compared my QTH with the assistance of ON7AN but other times it will be antennas, transmitters, receivers etc that I can compare using the help of fellow Hams that Network in the great Invention that is WSPR
My small and humble receiver seems to work well and is doing it's jobb.
The following day that Bernard put the WSPR Receiver on the Air and Network - I turned on a small Arduino based WSPR transmitter that is on the prototype stage at the moment and will try to finish up and sell as product as well.
The transmitter puts out 200mW and after few hours of transmission in to my 20m dipole Bernard was picking it up using his new receiver. It was particularly satisfying to me to see the connection on WSPR Net knowing both ends was using electronics that I had built.
I will finish with a photo of Bernards setup.
He is using a Raspberry Pi, an USB sound card, and a 7805 regulator to get really low-power station for 20m WSPR reception and in true Ham style have put it all on a bread board (actually if you look closely it seems he is using a section of a parquet floor, fancy! :-) )
Bernard - ON7AN setup. Uses 0.4A@5V DC.
Well done Bernard. I have to spend some time setting up aRaspberry Pi as well.
73 and see you all on the air and on the WSPR map.
//Harry - SM7PNV