[aprssig] PHG directivity

[Robert Bruninga]

>>> n0yxv at gihams.org 05/11/06 9:31 PM >>>
> I've notice that PHG can only do Circles. 
> Since almost none of the coverage patterns 
>I've seen really are circles...

No, That is only for omni stations.  If you have a 
blockage in one direction or a favored direction,
that is what the directivity digit is for.  It can 
offset the pattern by about 6 dB.  That's like a
12 dB difference in the favored direction compared
to the blocked direction.

> One case I know of the Digi covers better to the 
>West than it does to the East. ... So the circle 
>correctly shows coverage on the West side but 
>shows only relative coverage on the East side. 

I'm not sure I follow the english there, but that digi
should then be using a directivity digit in its PHG so
that the pattern is offset in the favored direction.
What is it's call, so I can look at its PHG?

>Another example is a Digi I have that uses a 5 
>Element Yagi. My PHG shows a circle but really
>should show more of an elliptical pattern.

A 5 element Yagi is perfect for the PHG directivity digit.
It has about 6 dB gain and so the offset pattern will 
clearly show on the map out about twice as far in the 
direction it is pointed

The directivity byte in the PHG will convey to the
users a realistic visualization of the coverage pattern 
for stations with offset covaerages...

Bob, WB4APR