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[aprssig] Re: TIGER maps what-s the problem?

Steve Dimse steve at dimse.com
Sat Jun 17 20:54:02 UTC 2006


On Jun 17, 2006, at 3:35 PM, Keith - VE7GDH wrote:

>> 2) The current APRS-Internet Filterning systems (I think)
>> will not recognize a message sending station until it sends a posit.
>> If this is true, then this is a big problem for D7 users who need
>> to send a message from a new location.  Pete can probably
>> correct me on this...
>
> This was from UI-View, not from a D7 (which I don't have) but from  
> a laptop that normally only has a TCPIP connection, I disconnected  
> from the APRS server, changed my callsign to VE7GDH-3 and deleted  
> the position in the station setup and then re-connected and sent a  
> message. Checking on findu.com, my message showed up there. I then  
> disconnected and put things back to normal... VE7GDH-10 and the  
> correct lat/long for the position.
>
> Then I went to my IGate (VE7GDH running UI-View32 of course!) and  
> disconnected from the APRS server. I then did the same routine and  
> changed the callsign to VE7GDH-3 and deleted the position. After  
> double-checking that I was disconnected, I sent a message via RF.  
> Again, I went to findu.com and looked at the station that I sent my  
> message to and my message was listed there. It would appear that  
> the APRS-IS didn't object to a message from VE7GDH-3 sent both via  
> TCPIP and via an RF connection and gated by another station.  
> VE7GDH-3 to the best of my recollection has never sent a position  
> report by APRS.

APRS-IS as designed never rejects any message. If there is a problem  
(and as Bob said, Pete would be the one to chime in here) it is with  
the filtering software. APRServe, the original hub program, had a  
port that consisted just of the message traffic, specifically for  
IGates with low bandwidth connections. This has now been supplanted  
by AHub and a filtering add-on. I am not certain, but I do seem to  
recall that the filtering software only passes messages to stations  
that meet the filter criteria. The criteria is generally based on  
position, so the filter must know the position of a recipient if it  
is to pass a message.

If this is indeed true, and if all IGates serving an area connect to  
the APRS IS through filtered ports, then a message will not appear on  
RF unless the recipient has transmitted a valid position report. This  
is not the original design of the APRS-IS, my intention was that the  
internet side of an IGate would see all messages, and the decision to  
transmit based on "locality", being defined as within n digi hops,  
where n generally equals 2.

Steve K4HG





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