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From: "MAL HAMILTON" <MAL@g3kev.freeserve.co.uk>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re: vector potential
Date: Wed, 24 Jan 2001 18:04:43 -0000
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-----Original Message-----
From: g3ldo <g3ldo@ukonline.co.uk>
To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Date: 23 January 2001 20:44
Subject: Re: LF: Re: vector potential


>Hi Rik,
>
>> I did a little test on saturday afternoon :
>> I did put the lower part of the loading coil (that is normally in
>> horizontal position) vertical (directly under the wire).
>> I did measure the antenna current and the signal strength of DCF39, in
>both
>> cases not the slightest difference.
>
>Interesting.
>
>Some time ago, while operating from Amberley Museum, we had a Tesla coil
>group giving a demonstration. It was though that this would cause
>interference with my operation, located about 1km away. It did not.
>Out of curiosity I took my mobile LF equipment and parked close (100m) to
>where the Tesla group were demonstrating. I enquired as to what frequency
>they were operating on. It seemed to depend on the size of the coil - small
>coils and small sparks used higher frequencies, around 200kHz. The very big
>coils operated on lower frequencies - around 70kHz - as you might expect.
>I set up the LF receiver with a short length of wire so that I could hear
>the stronger commercial stations. When the Tesla coils were fired up tuned
>around and heard - nothing!
>This surprised me. I expected, with that degree of power being used for the
>receiver to be overwhelmed.
>The Tesla coils were close wound with an annular metal capacity top from
>where the sparks were induced with an earthed wand.
>
>Now Toni, HB9ASB, used a coil as an antenna on LF, see page 58 of the LF
>Experimenter's book. This type of coil is known as the Normal Mode Helix.
>This type of antenna is incorporated into Rubber Duck antennas used with
>VHF/UHF handhelds.
>A mathematical analysis of this antenna is given, in the discussion of
>different types of antennas, in Corum's torodial antenna patent
application.
>At the end of this analysis is the following:
>
>"There is an alternative way to derive Equation 1. (from the analysis just
>described), which proceeds from the introduction of a fictitious
>conceptional aid. This very useful tool is a great assistance to performing
>field computations for helices and solenoids. Kraus has shown that a loop
of
>electric current, i.e., electric charges flowing around the circumference
of
>the loop produces the same radiation fields as those of a flow of a
>fictitious magnetic charges moving up and down the axis of the loop. The
>fields external to a helically wound solenoid can be found by assuming a
>flow of electric charges around the helix, or by assuming a flow of
magnetic
>charges moving along the axis of the solenoid. The latter computation is
>much simpler to perform analytically than the former".
>
>The word vector potential is not used but in a formula illustrating this we
>have.
>
>AR  = (|E subscript theta| / |E subscript phi|)  [The = sign has a delta
>sign over it - whatever that means.]
>
>
>The purpose of quoting this formula is not to try to blind you with science

That is hardly possible and you could be out of your DEPTH with the BOFFIN.
You can fool some  people some of the time but not all of the
time!!!!!!!!!!!!

>but to show that our mysterious A  has popped up again.
>
>Regards,
>Peter, G3LDO
>
><g3ldo@ukonline.co.uk>
>
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