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Date: Tue, 24 Feb 2009 09:49:07 +0000
Message-ID: <fc7eccec0902240149p687e999bve95de930ad4b7ed6@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: More WSPRing
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I already have probably one of the simplest (not sure about cheapest )
5MHz monitoring stations.   Active whip feeding into an SDR-lite Rx
feding into a cheap boot-sale (=A320 quid) laptop.  It doesn't need
internet conenction for 5MHz logging, but could have it if needed.

The only proviso is that the monitoring software ideally has I/Q
stereo channel inputs to give the sideband isolation, which many
laptops don't have.   For narrowband purposes, a simple RC phasing
network can be used instead (see RadCom Data column a few months ago.
 For 500kHz with a ferrite rod, an even simpler Rx ought to be
feasible.

Andy  G4JNT
www.g4jnt.com



2009/2/23 Mark <markhughes1@blueyonder.co.uk>:
> Hi all,
> Not withstanding the fickle nature of propagation, my WSPR / Grabber recei=
ve
> antenna is not the most efficient, and does suffer from an elevated noise
> floor compared to my main station antenna.
> Signals are typically 6dB stronger on the inverted L, though I have not
> spent any great effort quantifying the differences.
> One of the true benefits of WSPR is measurement of signal level variations
> at one location, but to get =A0meaningful data on relative strength betwee=
n
> stations would take many receive stations with identical equipment.
> That is of course eminently possible, a cheap PC and a standard ferrite ro=
d
> active receive system + simple SDR would enable a major propagation study.
> Most amateurs have a PC and internet, if a cheap design were published for=
 a
> WSPR monitor station, we could potentially get many listening stations QRV
> and gather a lot of interesting data. not many transmitters need be on, so
> no problem for non NOV holders.
> With other 'front ends' any band could be monitored.
>
> How cheap can we make such a system, is anyone interested?
> Mark GM4ISM
>
>
>
>
> ----- Original Message ----- From: "Andy Talbot" <andy.g4jnt@googlemail.co=
m>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Monday, February 23, 2009 9:20 PM
> Subject: Re: LF: More WSPRing
>
>
>> That's very interesting - =A0I appear to be 10 - 15dB better S/N with
>> you Johan (-5db S/N) at 1200km, than with GM4ISM (-20dB S/N) at 577km.
>>
>> Background noise levels ?
>> Sea path ?
>>
>> Andy =A0G4JNT
>> www.g4jnt.com
>>
>>
>>
>> 2009/2/23 Johan H. Bodin <jh.bodin@telia.com>:
>>>
>>> Solid copy in JO67MR Andy, including the CW ID!
>>>
>>>
>>> 73
>>> Johan SM6LKM
>>>
>>> Andy Talbot wrote:
>>>>
>>>> 503.870 +23dBm ERP running now, =A034.375% duty cycle ...
>>>>
>>>> Andy =A0G4JNT
>>>> www.g4jnt.com
>>>
>>>
>>
>>
>
>
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