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

[jrusgrove at comcast.net]

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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