Tuesday, November 20, 2012

20 November 2012

Today my main rig has spent even more time on other things than WSPR. Besides trying to work some PSK31 DX I have also been testing a beta release of K3 firmware. This new version has an improved CW decoder that is a bit less finicky about settings. It works very well but is still beaten by the Windows program MRP40 which I regard as the gold standard for CW decoders. As Wayne N6KR says, the MRP40 algorithm is probably ten times more sophisticated and the K3 MCU doesn't have enough code space for it.

I've been interested in Morse decoders since the first home computers and can remember keying in a program listing in BASIC from a QST article in the late 70s. Later I wrote a decoder in Hisoft Pascal which ran on my ZX Spectrum. It actually decoded strong, perfectly sent Morse but it was not reliable enough to be useful. More recently I tried implementing a Morse decoder in KComm but it was a total failure.

I didn't have a lot of success with PSK31 DXing on 10m either. I only made two contacts but I heard what would have been two new South American countries: HC7AE in Ecuador and CE4BRO in Chile. I didn't need to look up HC in a book as I remember from my teenage SWLing days hearing HCJB Quito, the Voice of the Andes!

I think band conditions were better today but they supported more propagation from Europe so there were higher QRM levels (and lower operating standards ;) ) I moved up the band to try and get away from all the IMD products but hardly anyone was listening up there so it was a bit futile.

Someone who did hear my CQ calls was Vito IZ7DMT. He was a whopping signal but was signing IZ7DMT/QRP. He told me he was running 5 watts from an FT-817 and was rather indignant that I wouldn't use the illegal /QRP suffix during handovers. Nice QSL though!

Here is the result of today's WSPRing:
10m WSPR spots @ G4ILO 20 November 2012


Paul Stam PAØK said...

Ji Julian, I know you like MRP40. I have tested the software too, but I think CWSkimmer is the best CW software. It can decode weak signals and more calls at the same time. Great software. 73 Paul

Alex Hill said...

I've built a PIC based decoder and found its only really good with signals >55. Similarly phone based ones are the same. Both were a bit of a disappointment in those terms. The weaker signals can be picked out by ear but not it seems by either the PIC or the software.

I've never used MRP40 and used skimmer many moons ago and that was excellent.

I am surprised that there isn't more software of that calibre (or am I missing something?)

Unknown said...

I used CW Skimmer until the trial ran out so I haven't been able to compare the two directly. The main disadvantage of Skimmer is that using it in a contest puts you in an Assisted category while a basic decoder doesn't.