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[aprssig] 30M APRS and digipeaters... STUPIDITY!

Bob Bruninga bruninga at usna.edu
Thu Jul 12 20:43:15 UTC 2012


This WIDE2-2 on HF is absolutely absurd!  

Go to a mountain top and LISTEN to what WIDE2-2 does to a normal APRS VHF
network.  You will hear not just your one TX packet and the first copy, but
you will hear as many as 16 additional copies from the surrounding digis!

DO it on HF and the original 3 second packet (at 300 baud) will clobber the
channel for the NEXT full MINUTE as every digi takes a crack at it, AND
WAITS ITS TURN.  Or COLLIDES with everyone else and NOTHING is decoded.

Please READ AND UNDERSTAND why digipeating on HF is simply dumb.

http://aprs.org/APRS-docs/HF.TXT

It was back in 1992, and still is today.  In fact, it is even dumber because
we now have IGates adding spatial diversity reception to every packet
transmitted!

Bob, WB4APR

-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Sergej
Sent: Thursday, July 12, 2012 2:04 PM
To: aprssig at tapr.org
Subject: Re: [aprssig] 30M APRS and digipeaters...


> We do need an updated modern best operating practice for HF operation.
>   We should either revisit the ECHO/GATE scheme or move to a new
> scheme closer to something like the WIDEn-N used on VHF.
>

Agree. My opinions based on long time HF aprs in this part of world:

1) Fixed stations with good RX/TX facility
(say low S0-S3 RX noise and 50 or more Watts of power) and fullsize antenna
can be WIDEn-n digi with max 2-2 hops.
Any more hops then 2-2 should be dropped down to 2 by digi or just ignored.
Substitution of WIDEn-n to real DIGI CALLSIGN when digi'ed is VERY
recommended.
Any other fixed (with human operator also) stations can have digi enabled
only on its CALLSIGN.

2) Any fixed station welcome as RX-Igate.

3) RELAY,ECHO,TRACE digi aliases is obsolete and not used on HF.

4) There should be proper WIDE2-2 DIGIs distance grid.
E.g. every 1800-2200km for 20m band and 1000-1500km for 30m.
(average daylight single hop of F-layer propagation)

5) Beacon rate for fixed stations not fast then 15-20min.

6) Beacon rate for moving stations not fast then 3-5min.

7) For message exchange use direct path as more as possible.

8) If need message exchange with station not in direct range try to find
best digi(s)
path and use digi CALL(s), instead of WIDE2-2 to not trigger all digis.

Comments, additions is welcome.

73, Sergej
ut1hzm

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