Audio Introduction:
WSPR (whisper):
Weak Signal Propagation Reporter.
You don’t have to be a licensed radio amateur to use the WSPRnet online map or the WSJT-X computer program for receiving stations. You can login as a short wave listener. The stations you hear will be shown with your icon on the map.
If you are only interesting receiving, and you don’t have a radio with a USB connection for a computer, don’t worry. You can take audio from your receiver, via the headphone socket for example, and feed that into your computer’s line or microphone input. You will need to go into the WSJT program on your computer and choose the correct audio input settings. On the WSPR screen you will need to tick the box marked ‘upload spots’ so your icon and the stations you hear will be shown on the map. Also, your PC must be connected to the internet.
Remember, the USB dial frequency on your radio is 1.5 KHz lower than the transmitted frequency (the centre frequency). You need to take the centre frequency you want to decode and subtract 1.5 KHz to calculate the Dial Frequency for USB.
Formula:
USB Dial Frequency = TX centre Frequency – 1.5 KHz
Example: Dial Freq = 5.250 MHz – 1.5 KHz = 5.2485 MHz
WSPR decoding is done +- 100Hz of the centre frequency.
It is usual to quote the Centre frequency and the operator needs to calculate the correct dial frequency.
USB dial frequencies in MHz:
0.136. 0.4742. 1.8366. 3.5686. 5.2872. 5.3647. 7.0386. 10.1387. 14.0956. 18.1046. 21.0946. 24.9246. 28.1246. 50.293. 70.091. 144.489. 432.300.
Propagation:
The WSPRnet online map is perfect for checking propagation. Say you’re on 10 metres and you wish to work Australia. Keep an eye on the map and, when you see stations from your part of the world hearing and being heard in VK land, it might be possible to have an SSB contact with Australia.
WSPR on 12 metres:
I’m now using WSPR with my IC-7300. My first attempt on 12 metres was most successful. Here is a map showing where I was being heard by stations as far as South America. My power was about 3 Watts. My antenna is a 5/8 vertical tuned for 10 metres so the SWR would have been very high. I cheated by using the radio’s auto ATU to keep the TX happy.
I’ve been having a great time with WSPR on various bands. There was a station in Greenland on 4 metres. I couldn’t hear him but he did show up on the WSPRnet map.
WSPR on 10 metres:
This was on 10 metres during the afternoon of 24/11/24 with the IC-7300 power down to 1%. I was being heard in Svalbard. JW1ITS, in International WSPR Beacon Project. My antenna is a 5/8 vertical 2 metres AGL.
Heard in China and Russia. This was on 10 metres at 0900 GMT 25/11/24. My antenna is a 5/8 vertical 2 metres AGL.
Australia on 10 metres:
I was heard near Melbourne at 1130 UTC on 1/12/24. Transmitter power on the IC-7300 set to 0%. Antelnna 5/8 vertical 2 metres AGL.
WSPR on 15 metres:
It’s truly amazing just how far a couple of Watts will travel on this band. I was using my doublet on this band, hardly an ideal antenna, and I was heard thousands of miles away.
Top Band – 160 metres:
Out of interest, I’m trying WSPR on top band. My aerial is a doublet, 30 metres top at 10 metres high… obviously not designed for 160 metres. In fact, it’s about 49 metres short! However, having a decent ATU, I can get 1:1 SWR. By the way, you can load a six inch nail on top band and get 1:1 SWR with a decent ATU. But, obviously, it will be a useless antenna. I’ll be testing after dark tonight (17/11/24) on 1.8366MHz. Power will be about 5 Watts to begin with. Will I be heard in America?
I wasn’t heard in America but I did reach Iceland and Turkey. I’m now using a 30 metres long end-fed antenna. The results were much the same as the doublet so I will be lengthening the end-fed in the hope that it will improve things.
VLF:
I tried my Miniwhip active antenna on two VLF frequencies. I heard F6KPL on 474.200KHz. I also monitored 136KHz but heard nothing.
WSPR Desktop Transmitter:
I’m awaiting arrival of a WSPR DesktopTransmitter from Zach Tech. Take a look at the link for information. It’s a standalone multi-band WSPR transmitter with built in GPS. Well worth buying if you’re into WSPR. With this little unit, I will ne able to transmit continuously from any location. All I’ll need is an aerial and a 5 Volt power supply. I intend to use the TX in the car on 10 metres using a 1/4 vertical antenna. Hopefully, the GPS signal will place me at the correct location on the WSPRnet online map.
