[Lowfer] Little PSK coming up to JD on 74.322...

Wed Jan 1 22:16:22 EST 2014

That 8.9 kHz work is absolutely amazing.  Stefan and Markus plus others won't slow it's progress until one or more make regular T/A crossings on that "audio freq"!!!

> From: jrusgrove at comcast.net
> To: lowfer at mailman.qth.net
> Date: Wed, 1 Jan 2014 21:59:09 -0500
> Subject: Re: [Lowfer] Little PSK coming up to JD on 74.322...
> 
> JD, Bob
> 
> Yes, it's always good to run tests as almost always something is learned!
> 
> The nice thing about software that reports some sort of SNR indication is the ability to analyze a 
> path over an extended period of time. It's a little less convenient, but one can infer the same 
> information with keyboard QSO modes or QRSS by looking at the quality of copy. If tasked with 
> testing a potentially marginal path (say coast to coast groundwave on 73 kHz) with currently 
> available software, I'd probably choose OP/OPDS since there is a wide range of different 
> speed/sensitivity levels to choose from ... if one isn't interested in the reporting aspect any 
> speed can be used on any band. One would expect the daytime groundwave to be fairly constant (as it 
> is on 60 kHz WWVB) so it should be possible to use the slow modes without running into significant 
> signal dropout due to fading. As you have probably read the guys in EU are experimenting with 
> OP-4hour on 8.970 kHz!
> 
> Based on the daytime strength of 60 kHz WWVB I would imagine if the station were moved to CA it 
> would still be easy audible copy here during the daytime. Doing coast to coast daytime groundwave 
> with an 'amateur' setup will, of course require weak signal techniques. Think I'd start with OP65 
> and see how that works.
> 
> Jay
> 
> ----- Original Message ----- 
> From: "Bob Raide" <rjraide at hotmail.com>
> To: "Bob Raide" <lowfer at mailman.qth.net>
> Sent: Wednesday, January 01, 2014 9:10 PM
> Subject: Re: [Lowfer] Little PSK coming up to JD on 74.322...
> 
> 
> > JD and Jay;
> > I found the results most interesting.  PSK31 has certainly been around a long time.  74 kHz 
> > operation to us has not.  It's new territory for me and interestingly has a "mind of it's own"! 
> > Was good test and the improved performance of QPSK31 was interesting.
> > It would be impossible to determine how far the ground wave "goes out" without actual on air 
> > testing.  And same with various modes at that freq.
> > It would be interesting to know just how far from the transmitter some of the proven good modes 
> > would reach.
> > Would a mode like WOLF reach California ground wave-or Jason-or OPDS32?
> > If I am not mistaken my signal was audible?  OPDS32 would maybe provide detection to another -40 
> > SNR ?
> >
> >
> >> From: listread at lwca
> >> To: lowfer at mailman.qth.net
> >> Date: Wed, 1 Jan 2014 19:47:24 -0600
> >> Subject: Re: [Lowfer] Little PSK coming up to JD on 74.322...
> >>
> >> That is an excellent article, Jay, along with its predecessor at John's
> >> site.  Should be most helpful.
> >>
> >> The main object of today's test was to kind of stretch folks' thinking about
> >> the daytime possibilities of LF.  The emphasis at 2200 and 4000 m has long
> >> been nighttime DX...and at this time of year, especially the Atlantic Coast
> >> guys to Europe and the Pacific Coast guys to Japan.  This is natural and
> >> worthwhile and rewarding, and I have no doubt it will lend itself to
> >> continued accomplishments for many years.
> >>
> >> The side effect, though, is that there has been only minimal attention to
> >> the daytime characteristics of these two bands.  It also tends to leave a
> >> gap in the middle of the country where it's already hard to generate
> >> interest in LF, since transoceanic opportunities are much more rare here.
> >> Bob and I went into today's demonstration knowing that the modes we had
> >> mutually available were not ideal for consistent communication, but given
> >> how reliable his signal has been here (especially at 74 kHz), we wanted to
> >> see just how far outside the box we could go* with a mode that's mainly
> >> thought of in connection with HF bands, and still see results.
> >>
> >> Bottom line, it was very gratifying to see keyboard-speed text arriving via
> >> almost 1030 miles of groundwave with 1 watt ERP.  I was pretty confident his
> >> signal was up to the task, but it was still a welcome sight to see it
> >> actually happening.  Makes me curious how slow we'd have to go to get
> >> reliable copy that could, for instance, then be relayed another thousand
> >> miles, and so on.  Just another fun opportunity to experiment and explore.
> >> Many thanks to Bob for his generous cooperation!
> >>
> >> 73
> >> John D
> >>
> >> (*We even seriously considered AMTOR/Navtex, but during the testing
> >> concluded that we'd need more signal or less noise. Maybe after dark some
> >> time when XRS4 or XEB is already lighting up the night sky.<g>)
> >>
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