The Weak Signal Propagation Reporter Network is a group of amateur radio operators using K1JT's MEPT_JT digital mode to probe radio frequency propagation conditions using very low power (QRP/QRPp) transmissions. The software is open source, and the data collected are available to the public through this site.

From Robin M1DUD:

"Just to let you know that Matt OZ6OM is WSPRng from Denmark today Sunday.
He is running the UKSMG stand at Odense and will be on WSPR all of today
hopefully giving a demonstration of how it works!!!

If you can listen for him on 50.293 or can be QRV it would be most welcome.

73 Robin."

How is the snr calculated and what is the bandwidth of the channel?



I have been running the WSPR software since about the 20th of October 2010 and have really enjoyed it. It's amazing to see how far your signal goes when you are running very low power of 5 watts of less.

To see my WSPRnet Bio, go to



Today I noticed some spots that didnt show up as spots, there seems to be a frequency drift of some 10hz form some folks on 10m. The signal should be perfectly redable but it slopes in the form of a J from about 155 hz to 124 hz. I'm wondering if their transmitter isn't as stable as it should be or if this is just some spurrious emission. I only seem to see it in the 10m and 6m bands. Other than that this has proved quite an interesting little program and beats the snot out of the CW beacon format. Cheers!

In the past several days I've seen quite a few WSPR signals that don't decode because they are mis-timed. This happens when one's computer clock is off by more than a few seconds, and it can be prevented by using an internet time service.

So I figured the mess out. My CLock update was not running and was pushed over 17 seconds ahead of CUT(GMT) CUT is COordinated Universal Time per NIST. HAHAH It only took me untill 2 am to figure out that I wasn't so coordinated. All fixed and appears to be working corectly using the NTP service as opposed to DIm 4. Still going to hang on to DIm 4 though It may prove more stable due to more requent updates.

A slightly amended version of WSPR 2.11, with the FMT package, has been posted on the WSJT Home Page.

Direct links are as follows:



There are two significant changes since r2247:

To all those who expressed interest in my software utilities that can help you make very accurate frequency measurements with your CAT-controlled WSPR setup:

These programs are now included in a new WSPR 2.11 package just posted on the WSJT Home Page:

There are many reasons why from a particular location the reported
TX and RX signal-to-noise figures can be very different. One obvious
cause is a different transmit power level at the station on the other
end of a particular WSPR-path. The positioning of the RX-antenna
relative to noise sources is however often the most determining factor.
This is perfectly evident if there is only one major local noise source,
and if it is OFF intermittently (during round-the-clock WSPR-operation).

At OH3MHA and similarly on various other locations we have observed that
things are generally fairly balanced at 10 MHz and higher frequencies, but
7 MHz and 3.5 MHz very often expose computer hash, internet data transfer
spectra (e.g. HomePNA), PLC, switching power supply harmonics and the like.
I do not have experience on the lower bands (1.8 MHz / 500 kHz / 137 kHz),
but there may be a slight advantage due to the fact that there the geophysical
background noise threshold is higher to begin with (to make a fundamental
distinction as opposed to man-made noise: geophysics cannot be manipulated).

OH3MHA was temporarily active on 7 MHz where antenna SWR is optimum with
a perfect 1:1 match, but the incoming man-made noise is very high, so that often
only a few stations are received for upload, while dozens of OH3MHA-spots
are reported by others. OH3MHA transmissions are now back on 10 MHz where
the situation is fairly symmetric, with about even numbers of in/outgoing reports
for each 2-minute transmission slot... We are presently experimenting with products (like the Webswitch 1216H) to have full TX-control
under all imaginable circumstances. Remote control could also be a solution
if one wants to install full WSPR-RX-functionality at a quiet remote location.

I will try to add figures and plots soon to my previous blog posting regarding the
analysis of the benefits of poor ground with vertical antennas for WSPR-traffic.

I have started to use WSPR only few days ago and I am exciting !
It was a lot of work to setup WSPR for my RX/TX Ensemble (KB9YIG SDR transceiver 1Watt output power). For receiving only I was able to use only Rocky 3.6, my external sound card Emu 0202 and internal Realtek sound card. But for transmitting I am using PowerSDR-IQ v1.12.20 by SV1EIA and EMU 0202 with VAC. I have found a lot of information about setup on
After first day of transmitting I have realized, that my long wire antenna (41 m long with antenna tuner MFJ-948) works well toward Australia :)

2010-11-01 05:22 LY2BOS 10.140199 -8 0 KO24or 1 IW4EGP JN64gb 1494 223
2010-10-31 22:02 LY2BOS 10.140190 -27 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 21:44 LY2BOS 10.140190 -23 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 21:34 LY2BOS 10.140189 -26 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 20:46 LY2BOS 10.140190 -22 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 20:38 LY2BOS 10.140190 -20 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 20:28 LY2BOS 10.140190 -20 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 20:16 LY2BOS 10.140190 -19 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 20:06 LY2BOS 10.140191 -20 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 19:54 LY2BOS 10.140190 -21 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 19:42 LY2BOS 10.140190 -25 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 19:32 LY2BOS 10.140189 -25 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 19:24 LY2BOS 10.140190 -24 0 KO24or 1 VK6ZRY OF78wd 12886 109
2010-10-31 18:48 LY2BOS 10.140192 -23 0 KO24or 1 VK6ZRY OF78wd 12886 109

I've come to the conclusion I need a more stable and accurate signal generator than my circa 1950 Precision E-200-C or my Heathkit Dip Meter to align the WSPR transceiver. I ordered an N3ZI DDS 2 VFO kit.

K1JT's station is a little south of due east from my QTH (near Detroit, MI)at Az 291 that would imply Az of 0 degrees is about due south and increases in a counterclockwise compass direction. However, I noted that contacts in England or Germany as listed in the database at approximately the same Az - which I think is incorrect, please advise, thanks...

I'm new as of yesterday, 30 October. I signed up because my local club has been interested in propagation and NVIS, and we will be working on some NVIS antennas during the next year. Thank you to QST for the links; thanks to CQ Magazine for the introduction to WSPR several months ago.

Especially for new WSPR users, I call attention to the following text from step #7 of the quick-start instructions from the User's Guide:

"Select a desired Tx frequency by double-clicking somewhere in the graphical display area. Available Tx frequencies fall in the range 1400–1600 Hz above the dial frequency. Clicking near the bottom of the graphical area gives a frequency near the lower limit, and clicking near the top puts you near the upper limit."