WSPR (Weak Signal Propagation Reporter)

by Gianni I1YHU (translated by I1UWF)

It is almost one year that I have an interest to the transmissions using WSJT or JT65A for HF and I visit regularly Joe K1JT site to be updated with new programs that he put in the web for every OM.

I have several times read documentation about WSPR, I had understood that it was a system to be used to study the propagation.

Going deeply this matter I have seen how big was my misunderstanding as the WSPR is an outstanding and completely new system to communicate. A good CW operator is able to "read" signals at -16 db, using JT65A we can demodulate signals at -28 db while WSPR arrives at -32 db. You switch on your receiver, find the frequency and you can hear only noise; you could think to switch off the radio but on the monitor will appear many calls.

I was interested to try this transmission mode and I was really surprised as my monitor displays several callsign of OM while from the receiver I could hear only noise.

WSPR QSO are not real QSO, we could define them as "virtual QSO" in fact I can listen a station and my system inform, via a link, a database that I have heard this station indicating also the report in db; in the next over I can see on the database that particular station has listened me indicating also the report in db. At this point, as it has been a bilateral listening, with a regular report, the QSO is valid.

Who would like to better understand how this system works can find in the web many solutions but according to my experience the best is the one of Joe K1JT.

You can find also an interesting documentation, in italian written by IV3NBA, with many instructions at: iv3nba.

I made the download from Joe K1JT site of the WSPR installation file, it take only few minutes and you are ready.

At first run the program is asking you to complete the setup, see first picture:



On the right side it appears a window you can enter requested data as your callsign, your locator using six characters, your input and output audio device (it is enough to click on the triangle and you will immediately see what you have in your system), transmission power in dbm, it is wise not exceed 5 watt and therefore you can let the suggested 37 dbm; if you like to reduce or increase the power the system itself shows you relevant value in dbm corresponding to watt, to conclude indicate the com for the PTT leaving the DTR protocol suggested by the system.

If you use the CAT with your TRX the PTT obviously must be None and furthermore you must tick CAT flag and insert requested values.

Let Tx fraction cursor on 20, it is used to determine in percentage the transmitting time.

Take out the flag from idle, it is used to actuate the button Tune to force the transmission in case of test.

Tick the flag Upload spots, in this way every listening you perform will be transferred to the general database therefore everybody can see the station listened from you and from others.

In Band menu insert the band you would like to utilize and then tune your TRX on the frequency that appears in the field Dial in mode USB, do not change the frequency in the TX field.

Now setup is finished, close the program and reenter again having synchronized you PC with exact time.

WSPR cannot work having differences bigger than +/- 1 second and therefore to be sure about the synchronism my PC clock is set with the atomic clock belonging to the Institute Galileo Ferraris in Turin; time to time I am forcing manually the synchronism, in this way I am sure to have differences lower than few milliseconds.

At the beginning the program put itself to receive in the following even minute and for about 120 seconds hears and then switch to transmission.

It has been a big surprise for me when during my first listening I saw the callsign of Joe K1JT; my system has forwarded a report in db to every stations and I can watch it linking to the WSPR database that is wsprnet.org/olddb.

The database works on a static page and therefore to see new QSO you have to click each time on the button Upload spots in the right upper corner.

Following pictures can clarify how it works:



As you can see I have heard Joe K1JT three times with signals of -6,-5 and -13 db, propagation was dropping down, it is normal in 40 mt. as the skip become shorter during the day.

Joe K1JT listened me with signal -11 db.

From the database you can see the locator of the transmitting station too, the output power, in this case Joe K1JT had 5 watt like me.



It has been a big pleasure to listen and to be listened from K1JT, not only for the QSO itself as I had a bilateral QSO also with New Zealand and always using 5 watt but particularly to have met Joe K1JT during the events happened last June in Sanremo in occasion of the Marconi's Centenary Nobel Prize for Physics.

I am now preparing cables to connect my radio FT-817, with an output power of 0,5 watt, to discover what happen using WSPR in such extreme low conditions; you can really enjoy yourself analyzing variations across different bands etc.

I have to thank Ivo IW1PAK as, during some test with JT65A, he told me about WSPR giving the first details and pushing me to begin.

I hope that somebody is interested to start WSPR after reading my notes.

73 de Gianni I1YHU

Italian version