From: "James Cowburn" <james.cowburn@virgin.net>
To: <rsgb_lf_group@blacksheep.org>
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Date: Wed, 3 Feb 2010 09:17:56 -0000
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Subject: LF: RE: QRP on 500kHz
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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