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[aprssig] Arrghh!!! Digipeating Being Facilitated On HF!

Stephen H. Smith wa8lmf2 at aol.com
Thu Aug 19 23:14:47 UTC 2010


  [Reposted from APRS Messenger Yahoo Group -- 
yahoogroups.co.uk/cross_country_wireless]


Thanks for all the feedback on the HF digipeater question.

It's interesting to see the views from both sides of the argument.

The original motivation was to provide HF APRS over PSK and GMSK for emergency 
communications and the option to digipeat to provide extra coverage into a skip 
zone would always be a useful tool to have available.

On the other hand I don't want to see a situation like we have in Europe on 30m 
AX.25 in Europe where incorrect digi paths are used.

I've uploaded v2.80 to the website and Files section.

I've added a single hop digipeater option.

There are two new click boxes on the main window to select HF digipeater and to 
add a WIDE2-1 digi path to transmitted packets. The click boxes are off by 
default and are not saved an program close so that the operator has to choose 
to digipeat or be digipeated each time the program is started.

For a packet to be digipeated it has to be received correctly and the checksum 
confirmed. The WIDE2-1 digi path is replaced with the digipeater callsign and 
re-transmitted with a new checksum. The digipeated transmission is always sent 
as GMSK-250. The original packet can be either PSK-63 or GMSK-250.

There are several restrictions on what is digipeated.

If the packet is a message to the digipeater station it won't be digipeated.

If it's a ?aprs or ?APRS query it won't be digipeated.

If any of the following text strings are seen in the packet it won't be 
digipeated: TCPIP TCPXX ?aprs ?APRS ?igate ?IGATE

Other changes in this version:

Option buttons for RTS, DTR or both for serial PTT output.

The font on the group message display has been changed to make reading easier.

If the serial port connection to an external TNC is lost then a re-start timer 
tries to re-connect again.

That's it for now.

73,

Chris, G4HYG



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

--

Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

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

*** HF APRS over PSK63 ***
    http://wa8lmf.net/APRS_PSK63/index.htm

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







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