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Re: LF: Re: WSPR Spots

To: <[email protected]>
Subject: Re: LF: Re: WSPR Spots
From: "Graham" <[email protected]>
Date: Sat, 21 Feb 2009 13:54:27 -0000
Importance: Normal
In-reply-to: <AC3B1FEE011A4FF781082DDA07637BD0@p4>
References: <[email protected]> <AC3B1FEE011A4FF781082DDA07637BD0@p4>
Reply-to: [email protected]
Sender: [email protected]

Mark,



I think 'we are looking at situation parallel with the argument of using video enhancement as evidence in the judicial system , in that the adjacent pixel decisions do not always result in a correct recovery of the original data .. and over lay filters / masks can be 'biased' I assume this is the case as the recovered call signs are in a recognisable format and not simply random data .. ?


I am coming to the conclusion that the single reported signal level is
barely adequate on 500KHz, an pretty useless when the QSB is fast.. what
WSPR software needs for studying propagation is perhaps 10 or 20 sig level
measurements per period,

Funny you should mention that , this page was started Nov 2007 , with the same in mind !

http://groups.google.co.uk/group/uk500khz/web/the-big-beacon-project

G...

--------------------------------------------------
From: "Mark" <[email protected]>
Sent: Saturday, February 21, 2009 8:17 AM
To: <[email protected]>
Subject: LF: Re: WSPR Spots


Hi all,
The spurious calls generated here are as a result of a wideband birdie that
wanders through the 500KHz band, probably a switchmode PSU
Not all the bad decodes get uploaded, so there would appear to be some
filtering of what is uploaded
What the software needs is a checkbox after each decode, so that the user
can mark bad messages, the system could them automatically remove those from
the database

I have also been analysing the spots by graphing signal strength, and
comparing for example my reception of SM5BHZ with that of other stations.
(for anyone interested I have used an Excel macro to download specified
spots from the web database, and put them in a formal easy to use with the
graph wizard)

I am coming to the conclusion that the single reported signal level is
barely adequate on 500KHz, an pretty useless when the QSB is fast.. what
WSPR software needs for studying propagation is perhaps 10 or 20 sig level measurements per period, just uploaded to the database for future study. I have suggested this to Joe, but I think he has higher priorities and no-one
else has requested anything similar

Regards
Mark GM4ISM
www.dc2light.co.uk


----- Original Message ----- From: "Andy Talbot" <[email protected]>
To: <[email protected]>
Sent: Friday, February 20, 2009 10:11 PM
Subject: LF: WSPR Spots


According to the WSPR Spot database, there is some "interesting" DX
being received chez GM4ISM.
Is there some carrier or coherent  QRM present to generate these false
hits?

Just got a WSPR generating routine running on a 16F628 PIC with AD9852
DDS combination.
At the moment it only operates at 100% duty cycle, but I'm Looking at
PN sequences for randomised transmission slots with 20/25/33% Duty
cycle operation.

Andy  G4JNT
www.g4jnt.com




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