Results with the new 500kHz transverter

WSPR reports received this evening (40mW ERP)

A decent evening testing the new 472/500kHz transverter with WSPR reports from 6 different stations (best DX 440km) and copying 3 different stations on OPERA Op4 mode. There is still a slight PA instability that needs to be fixed (probably decoupling changes), so there is a bit more optimisation to do.

472/500kHz transceive transverter

Rev C Transverter (one correction: o/p LPF cap 6n8, not 100n)

Armed with the sensitivity data in the last post I have now modified my MF transverter to add the receive parts, without a preamp. I used the same scheme adopted in my old transverter to automatically switch through the 500kHz (or 472kHz) signal on receive directly to the FT817. Only 4 additional parts were needed to make it into a TX/RX transverter.  As proof that the RX part is working I have just copied PA0WMR with a huge signal on OPERA Op4 with the signal passing through the transverter.

First 500kHz OPERA reports

Having managed to match my 6m long coax feed line (as a Marconi vertical) up to the 10/6m halo antenna on 500kHz by adding some inductance wound on a ferrite rod in the shack, I've just received my first OPERA beacon reports on the band from ON6EO at a distance of 220km and G0KTN at 210km. Reports were -30dB and -29dB S/N which is marginal.

OPERA mode on 500kHz

500kHz OPERA RX this afternoon (on left are my spots)

Having now uploaded the latest version of OPERA weak signal mode software I have been looking on 500kHz using my, as yet, untuned short vertical antenna. CPU load without waterfall is running at around 40-50% on my Dell Inspiron 630m and the PC is running in a stable way. So far copied PA0A, PA3ABK and M0FMT. If I can get the antenna resonated crudely I may try OPERA TX on 500kHz later this weekend.

Weak signal modes compared

There has been quite a bit of debate recently about just how good certain weak signal modes are when compared against similar modes. So, ON7YD has done some research and straw polling to compare them and published the results on his wonderfully informative website. He asked people to try to decode some weak QRSS signals by eye - these were at defined S/N ratios and compared the results against OPERA at various speeds and WSPR.

Amongst his conclusions is that "Opera8, QRSS10 (or DFCW10) and WSPR should have a more or less equal performance."  This is very much as I have found from practical experience on 136kHz where QRSS3 does not perform as well as QRSS30 which is somewhat better than WSPR. So, WSPR being much the same as QRSS10 seems spot on. The advantage of WSPR is of course the internet database reporting which allows you to see where you have been received. QRSS reports depend on someone decoding the signals by eye and then manually sending you a report, which rarely happens. So, WSPR remains my favourite weak signal beaconing mode.

ON7YD's graph showing the effectiveness of various weak signal modes

OPERA (weak signal mode) - a word of warning

Since installing Opera V1.0.4 a few days ago my Inspiron 630m Win XP PC has started to behave very oddly. For years it has worked in a very stable fashion with very few issues in 6 years of use.  Now it is slow (very slow) even when not using OPERA, CPU load is high and running Ccleaner, which usually takes a minute, took nearly AN HOUR to get rid of 156M of files to be cleaned up.  Now, I cannot PROVE the link, but the coincidence is remarkable.

To make matters worse, the software once installed does not appear to be listed in the list to uninstall. Not being a PC expert I am loath to just remove all the obvious files in case this damn program has left something behind that "leaves its mark".

The lesson is DO NOT INSTALL DODGY, UNSTABLE AND POORLY WRITTEN SOFTWARE unless you know what you are doing and you know how to get rid of it safely and completely.

OPERA, as a weak signal mode is interesting, but I am VERY unhappy that it has messed up my good old faithful PC.

OPERA - new weak signal beaconing mode

There is a new very weak signal beaconing mode being trialled currently on 136 and 500kHz called OPERA. The current version is available as a zip download at http://www.mediafire.com/?w74a061m48nv806 but this is a beta version and updates are happening quite fast at the moment, so best check the RSGB's LF reflector for the most recent version from Graham G4WGT.

Initial indications are this is even better than WSPR, which as we all know is an excellent QRP beaconing mode. I managed to decode SM6BHZ (just under 1000km) and PA0A tonight when using just my 20m separated earth electrodes (no antenna in the air here at all) on 136kHz.

Over the weekend I may give this a go with a few mW ERP on 500kHz and, when I get my vertical loop re-erected, on 136kHz too.

Early days yet, but a most interesting mode that does NOT need critical PC timing (unlike WSPR) and that can use the PTT line or VOX control to key the TX i.e. it is simple to interface rig to PC.