Thursday, 26 November 2015

630m WSPR

                    Happy Thanksgiving to those of you in the U.S.A.

It seems that the 630m WSPR digital crowd is growing quickly, with more new stations showing up every evening on the web's WSPRnet activity page. Most nights see activity from 80 or more stations, either transmitting or listening in WSPR mode on 630m!

WSPR is the 'Weak Signal Propagation Reporter' beacon-only mode being used by many of the stations presently transmitting on 630m, especially the U.S. experimental stations.

Those with the WSPR software (freeware and easily installed) usually have the program automatically upload their spots (stations being heard) to the WSPRnet page so that the transmitting stations are able to see where their signals are being heard. It also becomes quickly apparent, when examining the various spots, just how good or bad propagation might be at any given time.

WSPR Waterfall Displaying Detected Signals
Since WSPR is a non-QSO mode, the ability to observe propagation conditions, is its major feature. With transmission periods of just under two-minutes, and a very narrow FSK data information stream, WSPR can dig into the noise and copy signals that are often inaudible by ear ... some 15dB or more, past the audible level. Of course, audible signals are also demodulated as well, and will appear on your list of spotted stations, on the WSPRnet data page.

If you choose, you can also see your spotted stations in a Map mode, as shown at the top. This map shows the stations that I was hearing last night on 630m.

Along with the call and grid locator of the station being heard, the WSPR software also indicates several other bits of information, including the signal-to-noise ratio as heard at your location. Shown below is the decoded output from several stations following the two-minute transmission period.

06:58 WH2XXP 0.475662 -13 0 DM33 5 VE7SL CN88iu 1909
06:58 WG2XXM 0.475709 -6 0 EM15lj 5 VE7SL CN88iu 2610
06:58 WG2XKA 0.475723 -9 0 FN33lq 1 VE7SL CN88iu 3833

Note the SNR reports ... usually, signals stronger than around -14dB will be just detectable by ear with anything in the + range being pretty strong.

Shown below are the Tuesday night reports of local station, VE7CNF, and indicates the extensive area over which his WSPR beacon was reported. Toby is running a modest 5W eirp station from a suburban-sized lot. Analyzing the reports, it is apparent that many of these stations rose to audible signal levels at various times throughout the evening and would have probably been workable on normal CW mode ... even from the 'burbs!


There are probably many of you already listening to WSPR signals on HF and have yet to venture down to 630m to see what can be heard. The improved propagation conditions of late make this an ideal time to have a peek at 630m and see what you can spot.

Your low-band wire antennas can often hear surprisingly well below the broadcast band and you may be surprised at what WSPR can detect. Use the USB mode with your receiver set to 474.200 kHz and, if possible, upload your 630m MF spots to the WSPRnet. You can also follow up-to-the-minute activity on the 2200m/630m ON4KST Chat page which is always interesting.

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