From: "James Cowburn" <james.cowburn@virgin.net>
To: <rsgb_lf_group@blacksheep.org>
References: <12077821.1264946261487.JavaMail.root@wamui-cynical.atl.sa.earthlink.net> <38A51B74B884D74083D7950AD0DD85E82A1ACF@File-Server-HST.hst.e-technik.tu-darmstadt.de> <4C25D51A6FE646D5B8D9D37C87EA6BBC@lindavideo> <02E3EF3F48994AB88A1489042CE7EA02@JimPC> <284438.50947.qm@web87001.mail.ird.yahoo.com> <38A51B74B884D74083D7950AD0DD85E82A1AD5@File-Server-HST.hst.e-technik.tu-darmstadt.de> <00a101caa471$beaf7530$1bb2a8c0@vp2fc459c0ffcf> <20100203082523.6D257F3862@smtps02.kuleuven.be> <003001caa4b1$c5b831b0$0217aac0@desktop> <002a01caa4c3$28d86a10$8d01a8c0@JAYDELL>
Date: Wed, 3 Feb 2010 12:32:38 -0000
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Subject: LF: RE: Re: RE: QRP on 500kHz
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Hi Jay

Thanks for this.  Will do.  Have PMd you with further details

 
 
 
With best regards
 
 
Jim
 
 
Dr. James Cowburn

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of
jrusgrove@comcast.net
Sent: 03 February 2010 11:22
To: rsgb_lf_group@blacksheep.org
Subject: LF: Re: RE: QRP on 500kHz

Jim

Have been looking for your WSPR signal whenever you're active. The lowest
ERP from EU received here 
so far was +20 dBm from G0NBD...about a dozen spots over several nights.
Distance was 5198 km. The 
spots were in the -22 to -25 SNR range so reception of a station that is 6
dB below G0NBD should be 
possible. Please transmit whenever you can - there are at least several
stations on this side of the 
pond that routinely keep an eye on 502.4 kHz.

Jay W1VD  WD2XNS  WE2XGR/2


----- Original Message ----- 
From: "James Cowburn" <james.cowburn@virgin.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, February 03, 2010 4:17 AM
Subject: LF: RE: QRP on 500kHz


> Rik/LF
>
> That too has been my experience.   With 10W out (approx 50-100mw erp) I
can
> work 1000km stations on WSPR with SNRs of around -20dB to -25dB.  If I
> switch to low (1W so approx 5mW or less) I can still be copied by M0LMH at
> 200km and John PG in the Shetlands (916km) at -29dB, also LA3EQ (800km)
and
> others in D/F.
>
> Similarly in the recent dry spell I was getting around 12 to 15w into
> antenna, now it is wet that has dropped to 10W.  Sub-optimally I am using
a
> silver birch tree as the support for my inverted L and will likely be
> suffering losses due to the wire running close to the trunk and then over
a
> bough and out thru the branches.  A job for summer is to use a better
> support away from trees!
>
> Curiously my mid range reports  are the ones that disappear on QRP and the
> local ground wave signals collapse
>
> Obviously it has a lot to do with the noise at the Rx end too, if not more
> so than the output at the tx end
>
> My best dx to date on wspr mode is 1200km out to Lubos when he set up a
> quiet RX location but TF/SV/SP would be good.  I'm sure that with right
> condx and 10w there is enough in the link budget at 50mw to 100mW to get
to
> 2000km or so.
>
> If I can reiterate a plea from Roger G3XBM, if there are any 500KHz
> enthusiasts reading this who are in the range 1500km to 2500km from IO/JO
> squares, even if only on Rx then let us know when you are monitoring and
we
> can see just how far more modest stations can get with QRo/QRP/QRPp.
>
>
>
>
> With best regards
>
>
> Jim
>
>
> Dr. James Cowburn G7NKS IO92ub
>
> Icom 706mk2G, 10W inverted L 6m/30m
>
> -----Original Message-----
> From: owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Rik Strobbe
> Sent: 03 February 2010 08:26
> To: rsgb_lf_group@blacksheep.org
> Subject: LF: QRP on 500kHz
>
> In the past I had noticed that my antenna detuned several kHz during rain.
> As it was raining last night (not a bit) I took the chance to do some
> antenna measurements using low power (25W input, about 15W output).
> Due to the bad SWR the antenna current was only 0.3A, estimated ERP about
> 20mW.
> At one moment I unintentionally started a CQ instead of giving a
> carrier (hitting the wrong button on the keyer) but decided to let it
> run while noting the measurement results in my "lab book".
> To my surprise I was called by Finbar (EI0CF) and had a nice QSO with
> him, receiving a 559 report.
> Condx on 500 last night seemed average to me.
> Conclusion: with a few Watt in a modest antenna (lazy-L, 11m high and
> 25m long) one can work 1000km (or more) in CW on 500kHz.
>
> 73, Rik  ON7YD - OR7T
>
>
>