From: "James Cowburn" <james.cowburn@virgin.net>
To: <rsgb_lf_group@blacksheep.org>
References: <AANLkTin5sumGSuy3XGXNK1jxKthgldBJLcCQsKj54vzp@mail.gmail.com>,<4C1B29FB.7090502@telia.com> <BF4A524700075746A6467658DFC7102C5107CB1298@ICTS-S-EXC2-CA.luna.kuleuven.be>
Date: Fri, 18 Jun 2010 10:10:18 +0100
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Subject: RE: LF: Earth electrode loop and 500kHz ERP
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Hi Rik

I'm actually using an inverted L oriented E-W   7m/35m.   The vertical
portion is at the westerly end and goes up into a silver birch tree and
cross a branch at 7m and then goes in an easterly direction across my garden
through a porcelain insulator attached to an aluminium mast on my garage
roof.  The wire then slopes down for 3 metres terminated with a springy
bungee cord to allow for wind flex


The vertical end is linked to the loading coil (approx 500uh) and then
connected back to the shack via 60m of RG213.

SWR @ 502 is 1.2 and RL is -18dB  Impedance is 52ohms  as measured by mini
VNA

Rx is a standard ICOM IC 706mk2g.   ZLP interface to Dell D610 with integral
onboard soundcard.

The IC 706 is also used to transmit and generates around 15w of RF at 500khz

 
 
 
With best regards
 
 
Jim
 
 
Dr. James Cowburn
26 Birch Close
Broom
Biggleswade
Beds
SG18 9NR
 
T +44 (0) 1767 600522
M+44 (0) 7967 300152
E james.cowburn@virgin.net
 
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-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Rik Strobbe
Sent: 18 June 2010 09:57
To: rsgb_lf_group@blacksheep.org
Subject: RE: LF: Earth electrode loop and 500kHz ERP

Roger, Johan,

I had a look at the WSPR data on june 16 between 18 and 20 UTC (daylight):

At G7NKS:  both G3XBG and G3ZJO are at 46km, G3ZJO was in average 3dB
stronger
At M0BMU: G3ZJO (76km) is about 8 dB stronger than G3XBM (69km)
But I believe that Jim is using a loop for RX and  the angle between ZJO and
XBM is about 70 degrees, so that can cause some dB difference (depending on
how Jim's loop is orientated).

This can give a clue about the difference in ERP between Roger and Eddy.

73, Rik  ON7YD - OR7T

________________________________________
Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org]
namens Johan H. Bodin [jh.bodin@telia.com]
Verzonden: vrijdag 18 juni 2010 10:10
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: Earth electrode loop and 500kHz ERP

Roger,

the programs SOILSKIN and EARTHRES by G4FGQ (SK) will not answer your
questions
directly but they are related to your questions and they are interesting to
play
with (many of his programs are).

  http://www.zerobeat.net/G4FGQ/

73
Johan SM6LKM

----

Roger Lapthorn wrote:
> Questions:
>
>    1. Now, how big is the loop thus formed?
>    2. How much of this is within the ground?
>    3. What is the 500kHz ERP likely to be?