QRP Labs Ultimate3 WSPR beacon back in the game

Last year saw my rather nifty Ulitmate3 WSPR beacon giving up the ghost after having been placed in it’s long awaited custom made housing. As to why it decided it didn’t want to work any more is anyone’s guess but my money is on a broken cable somewhere.

With that in mind it had been sat on my desk for the best part of 6 months until I had the time and the inclination to get it working again. Part of the problem may have been trying to cram too much inside the case. I had diligently designed and built a PSU to provide a dual voltage to supply the beacon and the SKM52 GPS module but in hindsight, when I get the relay-switched LPF board built I was going to be making life harder for myself by trying to pack everything into the diminutive case.

I invested in a regulated 5V external PSU and the new recommended SKM61 GPS module from QRPLabs.com

The advantage of the SKM61 is it runs off of 5V, directly from the beacon – a few less wires to worry about. So, duly armed with a soldering iron I set about rebuilding the various interconnects and redesigning my case layout.


Ok, not very exciting I must admit but a bit more secure and screened than my last jury rigged setup.

The SKM61 fiited nicely onto a tiny off cut of veroboard and I added a set of connectors to allow easy changing or boxing up (if I get to it!)


Now with the moment of truth upon us, it was time to power everything up


Unfortunately the photo isn’t brilliant, as this time after a 5 minute wait, I was receiving a very nice heart beat sync pulse from the GPS showing that we had a GPS lock and location and time were being provided by the GPS satellites. A quick fumble through the menu system to change my callsign to my new one and we were off!

Screenshot 2015-05-23 18.04.54

Well, sort of. I was in the middle of the Solent! Now this caused a degree of head scratching as I sure as hell wasn’t maritime mobile and the flood defences around Portsea Island hadn’t sprung a leak as far as I was aware! After revisiting the settings in the beacon my only conclusion was that the latitude and longitude being provided by the GPS were off. My old friend Google didn’t provide any clues on this one so I posted a call for help on the QRPLabs forum.

Thankfully, someone who knows a lot more about this than me (aka the all round nice guy, Mr Hans “QRPLabs” Summers) came to the rescue. To quote the man verbatim

“WSPRnet is a bit strange. 

Yes, the WSPR protocol only sends the 4-character locator. If you switch on the extended WSPR protocol then it will send 6 characters but that takes two WSPR transmissions and there are other disadvantages too, so it is not a good idea really. 
However most stations in WSPRnet have 6-character locators, even though they are only transmitting 4-character locators. The reason for this is that WSPRnet stores the 5th and 6th characters internally in its database and adds them to the 4-character locator received over the air.
The exact circumstances of this are not very clear to me. But I know how you can make WSPRnet “know” your 5th and 6th character and put them on all the spots of your transmission, and on the map etc (so that you will be inside Portsmouth). Unfortunately it is NOT a matter of becoming a WSPRnet user (with username) and configuring your 5th and 6th character – that does not work, you still show up as 4-character. 
What you have to do is UPLOAD your own reception report. As soon as you upload a reception report (your reception of other people’s WSPR stations), declaring your 5th and 6th character, your 5th and 6th character are put in the database. You can do it by actually receiving WSPR stations in the proper WSPR program, and uploading the spots. But there’s another way too, that I know does work. If you look at the old DB page http://wsprnet.org/olddb notice on the top right side of the page, some fields for uploading your log. Here you type in a 6-char locator, and this is where WSPRnet gets the 5th and 6th character from, that it puts on your spots. You need to find an ALL_MEPT.txt file, you can google for it and download it. Then edit the file to have one date header and one single row, that can be a fake spot of yourself, e.g. at a time/freq you know you transmitted. Then upload that. It seems that WSPRnet doesn’t write this entry into the database, it recognises it is you spotting yourself and excludes it; but it DOES get the 5th and 6th locator characters into WSPRnet.”


So, in short because my last WSPRnet reports were under my old call sign 2E0DFU, M0XXF has no entries in the database. As such, until it does the 4-character locator will be used, placing me in the middle of the brine.

I had a rummage around for the ALL_MEPT.txt file inside the WSPR software installed on my laptop and couldn’t find it until I discovered that versions of WSPR over 2.0 name it ALL_WSPR.txt

Screenshot 2015-05-25 10.36.18

Now Hans had offered me a solution to my problem, but my old Stellar Labs receiver kit was sat on the desk making a forlorn face at me as it hadn’t been used since the end of last summer. With that in mind it took all of 3 minutes to plumb it into my laptop and fire it up. By changing my callsign details within WSPR to M0XXF, in under 4 minutes I had current database report entries listed under my new callsign and my location was safely back on dry land!

Everything is working nicely and my beacon has a nice metal enclosure to keep it safe. The next step will be to sort out a D-plug connector for the GPS antenna, an enclosure for the GPS module and build the relay switched LPF kit, but in the meantime I’ll just let it sit there happily doing its thing.

Screenshot 2015-05-25 13.59.50