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UI-View Bashing (was Re: APRS RF DX? (Was RE: [aprssig]APRS in Atlanta - flooding the network))

Robert Bruninga bruninga at usna.edu
Thu Oct 13 19:31:21 UTC 2005


>>> "hasan schiers" <schiers at netins.net> 
>You said:
>
>"I'd rather not cater to dumbing down of HAM radio
>to plug-and-play where we cannot assume that users
>have an idea of their height above average terrain
>and its importance in local RF communications."
>
>In response, I say:
>
>That's another problem....very, very few hams 
>have access to HAAT. I think  it is a very safe 
>assumption that 95% of APRS users have no 
>idea whatsoever what their HAAT is.  It's not that 
>they are stupid. Busy, perhaps lazy, 

Again, you are trying to be too precise in a very
imprecise world of RF.  Yes, there is a very
exact defination of HAAT as requried by the
FCC, when reporting the HAAT of a repeater,
but again, this is ONLY so that the FCC has 
a CONSISTENT value that is computed the
same way.

But I say, any Ham should be able to look out
his window and be aware of whether he lives
on a hill or in a valley, or is blocked in a direction
by a hill or has favorable coverage in a given
direction.  And further, to have some clue as
to how high is antenna is generally above
the surrounding terrain.  If he isnt aware of
his RF environment, then we have a long way
to go in Ham education.

> but actual HAAT info is scarcely to be seen. 
>I'll do an  experiment sometime. I'll ask every 
>single aprs op I talk to what their HAAT 
>is and report back the % who actually know.
> (after I ask them how they determined their HAAT). 
>Want to take bets on how low the percentage 
>is going  to be? 

Yes, obviously it will be very low and that is exactly
the problem!!!!!  If everytime they looked at their
APRS map, they SAW a PHG circle that is proportional
to their PHG, then maybe they would start "thinking"
about it and be aware of it.

And then maybe they would either learn about it or 
at least make their circle realistic" rather than simply 
ignoring  *the*single*most*important*parameter in 
VHF communications.

>My only concern is all the extra stuff that has to 
>be done (and it won't be in most cases) to arrive 
>at a PHG that is even remotely meaningful.

To  me it is trivial and obvious.  My antenna is in the
top of an 80 foot tree.  I am generally aware of the
neighborhood around me and generally I am lower
than most.  I estimate that my house is probably
about 20 to 50 feet lower than everything around me.
Hence, I choose about 40 feet as my Height above
average terrain.  I just dont understand the
difficutly...

>UI-View displays PHG with an add-on just fine.
> It seems to be nit-picking to be overly concerned 
>that it doesn't do it out of the box.

I did ignore this problem back when UIview first
came out. but now that the MAJORITY of all
users are u sing it, and only 8% of UIview users
are using PHG, this is causing a big impact on
user understanding and display of their local 
RF network and is having a big impact on our
ability to visualize our local RF networks.  It is
no longer a nitpick.  It is a missing fundamental
element in APRS at MOST user stations.

>It's not that PHG is simply inaccurate....it is terribly 
>inaccurate and creates totally false conclusions..

Thats not at all what I see here.  If you have
some bad PHG's, then fix those bad stations.  ANd
also I think your statement is clouded by overly high
expectations.  PHG is a relative display, not supposed
to be precise.  You simply cannot measure RF range
as precisely as you appear to be attempting.

>Practically no one I have met in aprs knows how to 
>calculate haat or where to get the info to do so. 

This is amazing to me..  ANd a real concern for the
future of ham radio if a person cannot estimate
his effective antenna height above surrounding
terrain.  Please dont try to apply the very precise
(but practically meaningless) FCC definition of
HAAT for repeaters to this very simple human 
observation of the relative  performance of their
own antenna location.

>This is a "practical" limitation of the PHG concept....
>yet PHG is out there en masse...  there are two 
>problems to be solved:
>
>1. UI-View32 users need to run the add-in for PHG. 
>When they do run the  add-in, problem number 2
> below surfaces.
>
>2. Anyone purporting to publish PHG data needs 
>to get it right. (or at least close)

Yes, so why sweep this problem under the rug
and keep shooting the messenger that the 
majority of APRS users these days are blind
to their practical RF ranges becuse not only are
they not asked for their antenna height, but
then the impact of it is not displayed so they
are really missing the most practical aspect of
local RF communicaitons (Antenna height)
which was FUNDAMENTAL to the pricinples
of APRS.

>Both of these are significant problems and they 
>stem from the same source:  USERS, 
>and the odds are really stacked against you 
>getting this cleaned  up<vbg>. 

I disagree.   I think users are very capable of estimateing
their antenna height.  SO the problem is not the users.
THe problem is:
1) Most of them are looking at map displays  with no
RF range information.  THus they do not get
ANY feedback as to what it means, whether it is right
or wrong, or its impact on communcations.

2) Since they dont see it, are not asked for it, and
dont use it, then of course, they dont have an 
interest in it and may claim not to understand it.

So I dont think it is the users.  It is the view 
and the APRS tool that they are using that
is not making them aware of this very fundamental
aspect of RF communicaitons.

Show it on the map and then people will pay
attention to it and have some incentive
to get it right.

Actually, I am surprised to get this kind of feedback
from Iowa where i thought it was pretty flat.  It
would seem to be very easy in most cases for
any user to visualize his antenna height.  Unless
agian they are entering height above sealevel.
If so, they yes, we have a big problem...

Bob, WB4APR




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