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From: John Rabson <john.rabson@numeo.fr>
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Date: Fri, 4 Feb 2011 18:36:04 +0100
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References: <AANLkTik25SxY1Uo0BLO5wCPPak_xr4ZnQzp4CbDqkAON@mail.gmail.com> <Pine.LNX.4.64.1102032010470.1022@paranoid.lipkowski.org> <EF9DB1FF-7808-4E78-8A91-99C5961CF353@numeo.fr> <AANLkTimhz7qdxYApxFDjs4VSbKhkbv7+FL=kj-HJESO4@mail.gmail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: Earth-mode or not earth-mode
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Warren,

The transmit signal was coupled inductively into the rail using a standard=
 cave radio resonant loop. The signal was recovered at the receiving end=
 using a similar loop.

If I recall correctly, the signal was starting to drop off noticeably at=
 1.6 km.  The tests were done in an area where there is substantial interf=
erence from LORAN C, so it may have been  signal-to-QRM rather than signal=
-to-QRN that set the maximum range.

Also, the receiving operator complained that walking a good mile on railwa=
y ballast* was making his feet hurt, and he would have to walk the mile ba=
ck to get out of the cutting. =20

*Note that it is not wise to walk on the sleepers (railroad ties?)  as it=
 is all too easy to lose your footing if they are wet or greasy.  I have=
 been there!

73 John F5VLF
              G3PAI

On 4 Feb 2011, at 16:22CET, Warren Ziegler wrote:

> John,
>    If this was conduction through the rail, why was it limited to 1.6kM?
> Was this the length of unbroken track?
>=20
> --=20
> 73 Warren K2ORS
>                 WD2XGJ
>                 WD2XSH/23
>                 WE2XEB/2
>                 WE2XGR/1