Message-ID: <00ef01c980ad$e06b5d80$0301a8c0@mal769a60aa920>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <004f01c9809a$708b5c30$0301a8c0@mal769a60aa920>, <497F3902.1070604@sighthound.demon.co.uk> <497F5976.5945.1B872C2@v.d.heide.on-line.de>
Date: Tue, 27 Jan 2009 18:34:23 -0000
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Subject: !QRe: LF: PROPAGATION WSPR
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Klaus
They are flogging a dead horse but cannot see it
mal/g3kev

----- Original Message ----- 
From: "Klaus von der Heide" <v.d.heide@on-line.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, January 27, 2009 5:59 PM
Subject: Re: LF: PROPAGATION WSPR


>
> Dear LF Group,
>
> we should clearly differenciate between all aspects.
>
> A propagation study does not need any information transfer
> via the radio path other than confidence on the identity of
> the station in focus. In that case, observing the carrier
> is best. So WSPR has no advantage over QRSS.
>
> On the other hand, WSPR has the advantage of automatic
> recording. But that is not an advantage of the mode, it
> simply is the lack of a corresponding simple program that
> does the same with a QRSS signal.
>
> If the propagation is monitored with the final goal to
> make a QSO at appropriate conditions, then the information
> transfer gets important. In that case, WSPR may outperform
> QRSS by a few dBs (at the same error rate).
>
> Nevertheless, WSPR is not very near to the Shannon limit.
> I spent nearly all my leisure time of the last year with
> the design of a new digital ham radio QSO-mode HD43 that
> comes as close as possible to the theoretical limit.
> I will send a preprint on request.
>
> 73 de Klaus, DJ5HG
>
>
>
>> mal hamilton wrote:
>> > On LF  I do not think wspr is the correct mode to study propagation
>>
>> Good points Mal. However CW for manual reception and QRSS, to be viewed
>> on a waterfall display, are fine for all manner of uses and in extremis
>> QRSS is probably more sensitive than WSPR. However QRSS requires the
>> receiving station to be actively watching the screen all the time, or to
>> save traces automatically and then manually review them, by eye, later.
>>
>> This is rather time consuming and laborious.
>>
>> WSPR may have it's downsides, and the problems last night with G0NBD
>> aside, I've never had any problems decoding anything I can visually see,
>> and also much that I could not hear and would be at the threshold of
>> QRSS useabilty.
>>
>> I have confidence that what I see reported by the software is a
>> reasonable representation of what was transmitted, and it's much easier
>> to quantify changes in signal strength vs time with the WSPR data than
>> estimating by eye the quality of a QRSS transmission.
>>
>> It may not be accurate in terms of actual reported S/N ratio, but it's
>> consistent from session to session, and gives numbers to work with, if
>> that's your interest.
>>
>> Not everyone can sit waiting for the brief propagation opening, so
>> automating the process at least adds another facet this interesting 
>> hobby.
>>
>> If it hurts no-one then what's the harm?
>>
>> Regards,
>>
>> John
>> GM4SLV
>>
>>
>>
>
>
>


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