[time-nuts] Common-View GPS Network

[Magnus Danielson]

On 04/16/2013 08:04 PM, Attila Kinali wrote:
> On Mon, 15 Apr 2013 23:00:49 -0700
> Jim Lux<jimlux at earthlink.net>  wrote:
>
>> the effect of a strong multipath (which is what the choke ring
>> suppresses) would be a LOT bigger than that..
>
> Uhmm.. to my understanding, this is not quite true.
> The choke ring does not surpress general multipath, but
> the waves from near and below the horizon, which are often
> full multipath issues.

Well, it's an approximation against the most likely sources, and has 
proven effective for exactly this form of mittigation. Arguing about the 
semantics fills no real purpose.

> You can see the choke rings as forming of a specific wave impedance
> (or wave resistance, if you want) in the region at the top.
> At other places, this technique is known as electromagnetic bandgap.

You typically put three spatial zeros for the relevant frequencies at or 
sligthly below the horizon, with rotational symmetric around the axis of 
the antenna.

Cheers,
Magnus