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[aprssig] 30M APRS and digipeaters...

Stephen H. Smith wa8lmf2 at aol.com
Thu Jul 12 17:12:17 UTC 2012


On 7/12/2012 12:42 PM, Bill Vodall wrote:
> 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. 73 Bill - WA7NWP


I believe the original ECHO scheme on HF was adopted to prevent inadvertent HF 
digipeating when TAPR TNC2s configured for VHF operation were switched to HF 
operation without resetting the internal configuration.   (Many TNC2 designs 
including the MFJ 127x varieties included a hardware alternate-action 
pushbutton switch that switched the unit from VHF 1200/220 tones to HF 
1600/1800 200-Hz-shift HF tones.)

If the unproto path of a TNC2 had been set to the usual WIDE (or in those days, 
RELAY,WIDE) for VHF and then switched to HF without reconfiguring, the path 
would be ignored, since HF digis would only respond to ECHO.    If you actually 
DID want digipeating on HF, you would have to explicitly reconfigure the 
unproto path in the unit to ECHO.

ECHO became the entrenched standard on HF for decades, until the recent influx 
of newcomers familiar only with VHF conventions started arriving on HF due to 
a) low cost soundcard software TNCs and  b) code-free access to all HF bands,

I don't think we need gating anymore, since there are now enough igate stations 
listening directly on HF that can pass HF packets directly to the Internet.   
HF-to-VHF gating is the legacy of Kantronics KAM  dualport HF/VHF TNCs that 
could do this (crossband digipeat) standalone with their internal firmware.     
(As I mentioned in my previous post, my experience has been that I can beacon 
pretty much anytime from anywhere in North America and show up on the Internet 
WITHOUT being gated to VHF first.)

Shortening the packet path from ECHO,GATE,WIDE2-2 to just ECHO (or better yet 
nothing at all) will significantly increase the chances of a posit being 
received successfully, since you are eliminating between 12 to 17 characters.


-------------------------------------------------------------------------------

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Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
Home Page:          http://wa8lmf.net


High-Performance Software-Only Packet TNC
http://wa8lmf.net/miscinfo/UZ7HO-Soundmodem-Install-Ver-0.44-Beta.exe

High Quality Calibrated Static Maps for Any APRS App
    http://wa8lmf.net/aprs/PM9_StaticMap_Export.htm

  Vista & Win7 Install Issues for UI-View and Precision Mapping
     http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7


"APRS 101"  Explanation of APRS Path Selection & Digipeating
   http://wa8lmf.net/DigiPaths









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