[time-nuts] Frequencies used for GPS

[Chuck Harris]

For what it is worth, the short dipole is made up of 3.5cm long halves,
and the long dipole is made up of 4cm long halves.

-Chuck Harris

Dave Martindale wrote:
> On Thu, Oct 20, 2011 at 06:52, Chuck Harris<cfharris at erols.com>  wrote:
>> Here is the standard antenna for the T-Bolt.  Not a helix, but
>> rather some sort of crossed dipole.
>>
>> The feed point is the corners of the two V shaped elements, forming
>> a sort of bowtie><    With the ends capacitively coupled to the
>> ground plane.
>
> But notice that unlike a bowtie, the two visible arms are different lengths.
>
> I would guess that the other side is similar, with the two long arms
> in a straight line and the two short arms perpendicular to that.  So
> you end up with one dipole that's too long for resonance, and another
> dipole (at right angles to the first) that's too short for resonance.
> The shifts away from resonance cause a phase shift of the current
> relative to voltage, with one dipole leading and the other lagging.
> And the phase shifts make it a circularly polarized antenna, instead
> of linearly polarized.
>
> (I'm not an antenna expert, but this explanation makes sense to me).
>
> - Dave