RE: LF: its back - maybe -

[Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>]

Dave, Andy,

 

from my own experience I have the impression that false decodes often occur in the absense of real decodes.

Last week I had WSPR runnig several nights on 137kHz (attempting to catch G3XBM) on my 500kHz antenna. Connecting the antenna just make the noisefloor (as given by the WSPR software) rising by some 5-10dB, so the antenna performs rather poor on 137kHz. I got no real decodes, but serveral false ones. Often the deccoding proccess took over 1 minute (on 500kHz with real bandnoise and signal it normally takes 5-10 seconds).

Also interesting is the rather frequent appearance of "twins": one false call shows up during the same decode session on 2 different frequencies.

 

73, Rik  ON7YD - OR7T 

 

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Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Dave Pick [davepick@btinternet.com]
Verzonden: dinsdag 21 september 2010 16:14
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: its back - maybe -

Andy

Yes, some very interesting callsigns coming up! Super DX... some of them appear to be in the middle of the Pacific ocean!
What causes that?

Dave.

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From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
Sent: Tuesday, 21 September, 2010 14:45:07
Subject: Re: LF: its back - maybe -

Several decodes of the QRP transmission at G3YXM, all at the -25 to -27dB S/N level, so right on the threshold.

 

Dave, you're getting quite a number of false decodes accordng to the WSPR database.  Inpulsive QRM perhaps ?

 

Andy

www.g4jnt.com

 

 

On 21 September 2010 11:47, Dave Pick <davepick@btinternet.com> wrote:

Andy

I've put my WSPR back on on 137.5 but as I was setting it up I heard a "G8IMR" CW ID so I'll be surprised if I don't get a copy!

Dave

By the way, I had a similar shed conflagration a few years back, it was better than yours - the fire brigade attended!

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From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
Sent: Tuesday, 21 September, 2010 11:10:10
Subject: LF: its back - maybe -

Hope I'm not typing this too soon, but monitor 137.53kHz (USB dial 136kHz) WSPR.

600 Watts again

 

A bucket of water is lying close by this time.  

The coil is now in a brand new plastic dustbin with the variometer control brought to the outside world on a plastic spindle.

 

Nary a bit of aluminium tape in sight

Andy
www.g4jnt.com

ps.  the WSPR message is still untrue.  Its nearer 17dBm ERp than the 13dBm is says.