Re: Halloween Coiling and the FCC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Dave wrote:
> I'd not expect this to be wholly effective.
> I routinely get 'worldwide' SW reception with
> a SW receiver, with whip, in the basement.
> Granted, coiling freqs are different.

Yes, it'll make 100 times the difference at 0.1Mhz than
it does at 10Mhz, for a basement with small 'aperture' :) 

>> you should find as you rotate
>> the radio that in one particular alignment the signal
>> vanishes almost completely.

> Less so if its riding the mains, or other
> wiring....

There should always be a null. Even if the source is spread out.
The vector sum of the separate components of the distributed
source arriving at the receiver will sum in *some* fixed
phase to give a total resultant vector.  So long as all the
phase relationships are fixed (nobody is moving) the resultant
vector stays fixed. Set the ferrite axis perpendicular to this
vector for a null.

> i believe the physics goes
>  with this...)
>  Loudest signal is 'broadside'
>  Sharpest  _direction_ is with the null (least
>  signal)
> Null is off the _end_ of the ferrite.

Yes, that's correct.  The ferrite rod responds to the
transverse H field, so the source must be broadside for
peak signal.  Aim the axis at the source to null the signal.
The null is generally quite sharp with a long ferrite.

Gary Peterson wrote:
> a well grounded helical resonator...Use your long-wave receiver
> to detect the signal, 

Pointless elaboration.  If you want to couple to the E-field, just
use a whip antenna, but you discard directivity.
--
Paul Nicholson
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