[aprssig] PHG in APRS and Xastir?

[VE7GDH]

Bob WB4APR wrote...

> PHG is intended to show RELATIVE performance in
> the RF domain which is what ham radio is all about.

That's kind of my point. Many people, myself included, fudge the PHG figures 
to try and get it to more closely represent real world performance. With 
fudged figures, they are kind of meaningless. At this point, I'm inclined to 
adjust my PHG so it shows a tiny circle on the map rather than one that is 
more meaningful in relation to the sometimes huge PHG circles that I see 
around me.

re relative to what...

> The 2 dB difference is not all that significant (in what
> PHG is trying to do), but it was supposed to be isotropic.

OK... I'll go along with that. It doesn't make a huge difference. Ummm... 2 
dB difference to what? Quarter wave? Half wave? hi Regardless of whether it 
makes a huge difference, it should be stated in the spec. I have always 
thought of gain in relation to a half wave. Antenna manufactures really seem 
to like using a quarter wave because of the inflated figures. Isotropic is 
kind of hard to build even if the antenna is in space, so for terrestrial 
use, it doesn't seem quite right to me.

> There are many greater errors and  greater discriminants
> in quantifying radio range that are more important.

That I can agree with!

> If you can point me to where I had preciously suggested
> "tweaking" them, I will be  happy to go back and
> change them, because I agree, it is getting people on
> the wrong track here...

I don't recall you suggesting it. It might have been over on the NWAPRS 
list. I'll have to do a search and see if i can track it down. In the 
meantime, I'm going to go back to "by the book" settings for my PHG. I've 
got nothing against PHG per se... I think it is when a PHG circle as shown 
on a map (full size or half size) and it is inferred to mean coverage that 
it becomes more meaningless. Perhaps that is my problem... that I am still 
trying to perceive it as coverage rather than something that is relative. 
None-the-less, my PHG circle is about to become miniscule compared too the 
ones around me. Probably be changed in the next couple of hours or so.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"