[aprssig] 9600? Faster?

Robert Bruninga bruninga at usna.edu
Thu Jul 7 09:29:41 EDT 2005


>>> vk4tec at tech-software.net 07/07/05 3:13 AM >>>
>I did some testing co-located 1200 and 9600
>9600 does not seem to reach as far as 1200
>mobile environmet harsh to 9k6 signals

Same here.  We did extensive tests with 4 different
radios over 200 feet separation using lab attenuators
and a very long run of RG58 to eliminate any chance
of leakage.  The diffrence was 7 dB.  So it takes
50W at 9600 to equal 10W at 1200 baud.  Or
about half the range.

And this does not inlude any differences due to multipath
in the mobile environment...   I see no advantages at
all to 9600 for APRS (except to use the 9600 baud
satellite)...  Bob

-----Original Message-----
From: Curt Mills [mailto:archer at eskimo.com] 
Sent: Thursday, 7 July 2005 3:55 PM
To: TAPR APRS Mailing List
Subject: Re: [aprssig] 9600? Faster?


On Wed, 6 Jul 2005, Phillip B. Pacier wrote:

> We've been doing some experiments in So Cal with 9600 APRS.  Frequency in
use
> here is 438.975.  Equipment generally being used on the digi/igate/home
client
> end is the KPC 9612, and mobiles use D7/D700 equipment.  Initial tests
show
> that it works better than most people will tell you.  I'll keep you
updated.

Per Bob King, K7OFT, posted on the NWAPRS list just today:

"UHF APRS SYSTEM IN PUGET SOUND AREA IS ON 440.875 MHz Simplex 9600
Baud."

That's in the Seattle, WA, area.  He also mentioned that it is
important to adjust the deviation with a good service monitor to
3kHz.


Bob Donnell, KD7NM, mentioned this:

"With several 9600 baud projects under our belts over the years,
here in the Seattle area, we've found that +/- 2.75-3.00 kHz
deviation to be the target range, when used with filters designed to
work with a +/- 5 kHz deviation FM environment."

--
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer 
  Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me:  I picked the coordinate system!"

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