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From: "Ashlock,William" <William.Ashlock@bocedwards.com>
To: rsgb_lf_group@blacksheep.org
Date: Sat, 2 Aug 2003 13:30:09 -0400
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Subject: LF: RE: Re: 500m drums of coax  dipole
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David,

I hate to break the news to you but theory and loads of experimentation have
shown that the horizontal portion of a wave this long is short-circuited by
the ground surrounding the transmitting antenna. Therefore a horizontal LF
dipole is very ineffective at any practical height above ground. This why
verticals and loop antennas (mounted in the vertical plane) are used
exclusively at these frequencies. You may find, however, that your long
dipole turns the conductive portions of the soil into some kind 'ground
antenna' having a vertical component... so I wish you well. And keep us
posted!

Bill A

-----Original Message-----
From: captbrian [mailto:captbrian@ukonline.co.uk]
Sent: Saturday, August 02, 2003 8:18 AM
To: rsgb_lf_group@blacksheep.org
Subject: LF: Re: 500m drums of coax dipole


Is there the slightest evidence that 136 propagates  (propogates?) by
scatter or reflection.? I assume most of a 2" high dipole radiation goes
straight up to Mars.

Bryan
-----Original Message-----
From: G0MRF@aol.com <G0MRF@aol.com>
To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Date: 02 August 2003 11:47
Subject: LF: 500m drums of coax?


>
>
>> >Are you making a coax dipole for 136?
>> >
>> >73
>> >John Rabson G3PAI
>>
>I've always wondered about dipoles / loops at 136k?
>A 'dipole' just lying on rocky ground where the water table is many metres
>below the surface could be quite effective. The angle of radiation would be
poor
>but the efficiency may not be as bad as first suppossed. One advantage of a
>big antenna on the ground is that it can't fall down and, for the local
>planning committe, it's less than 9 feet high.
>
>Some time ago I tried to simulate this by making a dipole for 21MHz and had
a
>number of QSOs through it while gradually lowering it's height and
retrimming
>as I went. I managed to work Romania were I sent "Ant dipole  5cm agl".  I
>have no idea what the Romanian though of this madness and he didn't stay
around
>long to find out.
>Incidentally, at about 2 inches off the ground the antenna was resonant at
>about 20% less than it's normal 'free space length'. Never did find a big
field
>to try it on 136k.
>
>73
>
>David  G0MRF
>


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