Is FT8 and psk31 generally use around 20 to 30 watts maximum, as a "social rule", so that one station would not be too strong as to mask out other station, due to agc of rig?
On Saturday, December 29, 2018, Jim Brown <k...@audiosystemsgroup.com> wrote: > On 12/28/2018 4:54 PM, Simon wrote: > >> Hi K9YC, >> >> Many thanks for the detailed analysis. >> >> 1. Sorry, I do not understand why u said, quoted, "Gauging by the FT8 >> signals centered around 7075 kHz, I'd call this QTH pretty noisy". This is >> the FT8 band at 7074kHz, usb and wsjt-x decoded good copy of traffic. >> Those are wanted ft8 signals. >> > > I'm using their strength as a guide to the strength the noise sources I > identified. > >> >> Ft8 Traffic was busy, 4 decodes per 15 seconds cycle. Strongest signal is >> 4 dB snr. Most are better than -4dB snr, rare one was weakest at -19 dB. >> From call sign, many are from Indonisia, Australia and new zealand, 4000km >> from Hong Kong sota qth. So, it was good received signal from 4000 to >> 6000km away. It was healthy signals. >> > > That's not a lot of decodes -- I regularly decode several dozen signals on > each pass on the HF bands. > >> >> 2. The sota site has no AC utility electricity and no street lamps, it is >> a laws protected country park area where they preserve nature. >> >> 100 meters away is a public toilet with solar panel and pir triggered led >> lighting, which should be off as there is likely no one in toilet. Solar >> panel was zero output as it was dark, 30 minutes after sunset. No charging >> pwm noise. >> >> 500 meters away, and blocked by hill profile, as 100 meter lower, is a >> ranger office. Should be all person off duty at that time. Sure, there may >> be some smps still running. >> >> Up 150 meters, are two airport long range survilance radars, one primary, >> one secondary radar, with Powerful smps inside. Radar range about 700km for >> the hong kong fir, flight information region, from hong kong to taiwan to >> philpines. >> >> There is a residential estate, 500 homes, 30 floors buildings, 2 km away, >> with all kind of smps inside, computer, fluroresent lighting, led lighting, >> vfd motor drive for lift, etc. >> > > It's hard to get away from noise. In essence, all of these noise sources > are added together to form the noise floor. To find a dead quiet band, you > almost need to be tens of miles from sources. One of the few times I've > encountered that was a county expedition for the California QSO Party three > years ago in a very remote part of Trinity National Forest. No homes, no > radio sites, nothing as far as the eye can see from our site looking out > from about 1,000 ft above the ground sloping away from us. > > 73, Jim K9YC > > > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel >
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