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.

1 Watt to 9el Tonna

KP4MD WSPR station has been off the air since mid March 2011 due to hardware problems (recalled overheating HP computer due to a defective Nvidia GPU chip).

I'm in the process of relocating to another house and have no proper antenna. I stuck a mobile whip for forty metres on a 16 foot pole and pushed it up inside the foliage of a large cherry tree in the garden. Unsurprisingly, not many contacts on forty in comparison to the horizontal dipole at the other house.... Until I found WSPR, that is.

If your running a flex grab the latest full release of 2.0.22, in 12 months its come a long way ! The 1500 is tops for stuff like WSPR and super compact for the briefcase. Camping or Hotel room working it goes with you and runs no fuss and no crashes ! It makes very good use of the new high performance small notebook processors. Its now my favorite radio.

With the arrival of Tronson RF attenuator (model RA1728A)
I was finally ready for more low power experimenting.
Easter Friday afternoon was ideal time to tune into 40m WSPR.
An email notification about experiment was sent to LF reflector
and couple of locals quickly joined in.

The very frist transmission was done with barefoow Genesis G59 transceiver running 10 mW:

10 milliWatts

2011-04-22 02:32 VK2DX 7.040060 -18 0 QF56oe 0.01 VK3DB QF31dt 657 221
2011-04-22 02:30 VK2DX 7.040062 -6 0 QF56oe 0.01 VK1DSH QF44ms 253 231

The G59 10 milliwats signal was an easy decode over the distance of 657Km
so power was immediately reduced to 1 milliwat (10dB attn)
Signal at this power level was barely detectable at VK3DB, but good enough for decode at -29 s/n.

1 milliWatt
Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2011-04-22 03:12 VK2DX 7.040060 -15 0 QF56oe 0.001 VK1DSH QF44ms 253 231
2011-04-22 03:10 VK2DX 7.040059 -29 0 QF56oe 0.001 VK3DB QF31dt 657 221

With additional 10dB attenuation and 100 microwatts output,
the signal was still an easy copy over the distance of 253 Km by VK1DSH.
Actually, Dale decoded almost every transmitting sequence!

100 microWats

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2011-04-22 03:50 VK2DX 7.040060 -20 0 QF56oe 0.0001 VK1DSH QF44ms 253 231
2011-04-22 03:48 VK2DX 7.040060 -19 0 QF56oe 0.0001 VK1DSH QF44ms 253 231
2011-04-22 03:44 VK2DX 7.040060 -24 0 QF56oe 0.0001 VK1DSH QF44ms 253 231
2011-04-22 03:42 VK2DX 7.040060 -23 0 QF56oe 0.0001 VK1DSH QF44ms 253 231
2011-04-22 03:40 VK2DX 7.040061 -21 0 QF56oe 0.0001 VK1DSH QF44ms 253 231
2011-04-22 03:38 VK2DX 7.040061 -23 0 QF56oe 0.0001 VK1DSH QF44ms 253 231

Just put a 7.5m vertical on the back fence. Couple of counterpoise wires along the fence. Self-resonant about 8.6MHz but tunes well on 40-6m. Will shorten it tomorrow to be self-resonant on 30m, but in the meantime, the LDG Z-11 ATU seems to be doing the job. Eventually a remote switched loading coil to accomodate 80-6m is in the plan.

Much more lively than the experimental 30M (horizontal) flat-top (in the walnut tree to the east and the plum tree to the west) fed with 10.7m 300 ohm ribbon that I have been using for the last year on 30-10m.

For the last two days I have been monitoring WSPR signals on 7, 10 and 14 MHz and uploading spots. It is amazingly good though my reasonably quiet receiving location is a help. Surprises have been the relatively close VK2 stations heard at less than 200km, and the much more distant EU and NA signals heard on all three bands at various times of the day. Also some of them have been quite low powered, as low as 23 dbm or 0.2W. As a nice additional touch today, one of the stations heard was K1JT.

What a great piece of software! Thanks, Joe!

A smashing success with this little baby, within 15 minutes of installing the power connector it's up online and on air. With the VAC & CAT for this work this Flex1500 has real sex appeal. Mmmmm nice ! No old suit case style radios and sound card interface units, all software, all sleek and modern.

Today I stop my WebTRX and let run WSPR. I use WSPR before only from home for little tests but it is so interesting, that I will run it now longer. I let it run for first tests simultaneously on 15 and 20 Meter on a 2 Element Quad. I beam now 310 degree. If I find a program that can turn rotors which used HyGain DCU1 or Yaesu GS232 protocol by time, I turn it in the morning time to east. Any ideas?
On 10 I try to run WSPR from home, but not 24h a Day.

I'm getting some very strange decodes, so I'm not quite sure what's going on.

I'll let it run for a while, tx on 144.489,469 MHz.

Latest beacon design has 16 stored frequencies covering all bands 1.8 to 50MHz selected randomly. AD9852 DDS generates WSPR directly Feeds to broadband 6W PA driving untuned 7m high vertical antenna

I've been running WSPR for the last few weeks with just 50mW. Results so far are very encouraging, considering the less-than-ideal setup here.

I'm producing 50mW in the same way I did 100mW - setting the FT-897 to 5W, then backing off the audio into the FT-897 until the external power meter reads ~50mW. It's not an exact science, but if anything there's likely to be less than 50mW actually ending up being radiated!

Well pleased, I've finally managed to be heard in Australia. VK1UN on 10MHz SNR -28 dB!

Winter is easing its grip, but it is not yet time for antenna work, so the
anti-parallel dipoles mentioned in the previous post will have to wait.

While the weather is warming up, the 85 watts dissipated by the IC-761
during WSPR-reception is a bit of a waste; soon the shack will need
additional cooling with all equipment running. Therefore a "hundredfold"
reduction in rx-power is very welcome. Presently 15 volts 40 mA is fed
to a 7812 regulator followed by a 7808 to provide 12 and 8 volts bias to
four 8-pin chips, namely a SA612A - NE592 - SA612A - LM318H string.

SA612A mixers have very low bias, so they are prone to overload and
IMD when fed with wide input spectra. In this prototype receiver some
risks are taken, but narrow pre-filtering is expected to minimize the IMD-
problem. Due to the availability of standard crystals for certain frequencies
the 10140.2 kHz band-center seemed within reach with a 4.000 MHz and
a 6.144 MHz crystal. Both had to be pulled down a little off their nominal
frequencies for WSPR action. So we are talking about a superhet.

The first SA612A has the 4 MHz crystal in its oscillator section so
6144 kHz is serving as the intermediate frequency. Actually another
6144 kHz crystal is used as the IF-filter in the NE592 stage between
pins 2/7. It is in fact not a straightforward filter: it kind of "shorts"
two emitters of the NE592 at X-tal series resonance, which peaks
the amplifier gain enormously at around 6140 kHz. Bandwidth is not
much more than the 200 Hz WSPR-band, so it is quite a remarkable
response for a single high-Q component in that particular circuit.

The second SA612A makes a 6144 kHz crystal oscillate round about its
nominal frequency, so both the 4 MHz and 6144 kHz crystal have to be
pulled down with a series coil to arrive at band-center 10140.2 kHz with
1500 Hz BFO offset, actually in LSB mode. As standard WSPR offers

Please ignore my info spots 2011-04-01 07:24
No correct power info. Sorry. Run WSPR in XUbuntu
Now all ok! Good bay Windows :-(((

I am running a stand-alone WSPR beacon with my qrp SDR Cube with no stickin' PC! 1 watt in a G5RV on 40 m

Today I started running WSPR on my HCJB Pappradio SDR-Receiver. It's receiving only. Running on an 22m endfeeded indoor antenna I would see what this little thing can receive in WSPR Mode.

My handle is Basil from the City of Malabon ,Metro Manila ,Philippines

You can visit my qsl information at

I use the WSPRnet whenever I need to contact stations who are on the map.

So if I see your call-sign I will not hesitate to contact you 73 and Mabuhay! de Basil


Time for the transmission:

Every day from 20 to 24 h GMT

Dias, frecuencias y modos de transmisión para el Periodo de Actividad en 500 kHz

Activity Period fron 1-4-2011 to 30-4 2011

Día Día de la semana Frecuencia (Dial) Modo Shift a portadora = 1500 Hz