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[aprssig] FW: [nwaprssig] D700 UHF APRS DIGI

scott at opentrac.org scott at opentrac.org
Mon Sep 25 19:50:58 UTC 2006

Why use a D700 as a digi?  From what I've heard, it has a hard-coded 500 ms
TXD.  That completely destroys any increase in throughput you might get by
going to 9600.  You could put a LOT of FEC data on the packet, though!


From: aprssig-bounces at lists.tapr.org [mailto:aprssig-bounces at lists.tapr.org]
On Behalf Of Herb Gerhardt
Sent: Monday, September 25, 2006 12:32 PM
To: TAPR APRS Mailing List
Cc: K7OFT Bob King
Subject: [aprssig] FW: [nwaprssig] D700 UHF APRS DIGI

Since the TAPR APRS list seems to have come to a slow crawl lately, maybe
some of the members who are interested in new APRS development want to join
our NW APRS SIG and follow the development of 9600 baud APRS.
Bellow is a message of a discussion we have been having for about a month
now on 9600 baud UHF APRS that we are experimenting with on the NW APRS
Group Network.  It looks like we are coming up with another innovative more
efficient APRS network.  Maybe those of you who are innovative and curious
on helping to pioneer a more efficient APRS Network should subscribe to our
list to follow our development.  Maybe some other congested areas want to
give 9600 baud a try.  I am sure Bob King K7OFT would be more than willing
to help you get started.
You can subscribe to our list at our web site below.
Herb, KB7UVC
NW APRS Group, West Sound Coordinator
Our WEB Site:  http://www.nwaprs.info <http://www.nwaprs.info/> 


-----Original Message-----
From: nwaprssig-admin at nwaprs.info [mailto:nwaprssig-admin at nwaprs.info] On
Behalf Of David Dobbins
Sent: Monday, September 25, 2006 9:40 AM
To: nwaprssig at nwaprs.info
Subject: Re: [nwaprssig] D700 UHF APRS DIGI

Thanks to both Bob and Scott for their efforts. We're breaking new ground
here. Far as I know, there is no other APRS interest group with a 9600 baud
UHF activity. The plan to expand the system here in Spokane is coming along.
I'm still looking for a home for the 9600b digi. It needs to be mountaintop
or tower top somewhere near Spokane. 

I think we have the digi settings all worked out. We'll leave them on the
wiki pages, but I will duplicate them to the website shortly, now that we
have settings ironed out. This is critical with using a D700 as a remote
digi, because unlike the KPC-3, there is no remote connect to make further
changes. It would take another trip to the hill for those changes. 

Come on Portland OR and Vancouver BC, any interest in your neck of the

Let's spread this good stuff faster than the bird flu!


On 9/25/06, R.M. King <krm1012 at qwest.net> wrote: 

I'm not sure, but Scott may have been referring to the original file we used
to set up the D700 on UBALDI.  That file is stored on my home computer and
my laptop.  It has been modified to correct for the BEACON E 15 error.  It 
has been changed to BEACON E 90.

By the way,  I did some testing with the D700 DIGI on Baldi to test the
decrementing feature of WIDEn-N.  The results of the testing show that the
D700 DOES indeed decrement a WIDEn-N packet.  And that was done with the TNC

set in the configuration shown on the wiki page.  I would encourage others
to verify this.

The test that Scott just finished this weekend when he traveled to Eastern
Wa. and earlier tests I have done in Eastern Wa and Puget Sound, and 
comments from others taking up 440.875MHz 9600 Baud operations here should
once and for all put away the commonly held notion that you need super
strong signals to work 9600 Baud.  It is simply not true.  My field tests 
indicate that 9k6 works as well as and in certain situations, better than
1k2 operations.  Give it a try!

Scott, thanks for putting the APRS 9k6 Baud DIGI on Baldi.  It will
certainly open lots of eyes.

Bob King

nwaprssig mailing list
nwaprssig at nwaprs.info

David Dobbins
Medical Lake, WA 

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