Mutiple IGates, Same Callsign/SSID

[Rusty K7RMO]

The Amateur Radio Group of Oregon is planning to install multiple receive-only IGates in under-served regions of Oregon. Our plan is to use WA7RGO-10 for each of them. Will this cause any problems in the aprs.fi world? At this time we don't know how many will be deployed but it could eventually be ten to twenty or more.

Thank you,

Rusty K7RMO

[Heikki Hannikainen]

Yes, it will cause problems on aprs.fi. They'd all be a single igate, and
only one location can be shown for a single callsign-SSID at a time; if
they'd report their positions it would draw an ugly mesh on the map. Also,
only one set of statistics collected per callsign-SSID.

Even worse, it will cause packet loss on the APRS-IS network, so it would
cause problems outside aprs.fi. If WA7RGO-10 (A) is connected to APRS-IS
server 1, and another WA7RGO-10 (B) is connected to APRS-IS server 2, then
APRS-IS server 1 will drop all packets transmitted by igate B and APRS-IS
server 2 will drop all packets transmitted and gated by igate A.

This is due to one of the loop prevention algorithms in the APRS-IS
servers - if it has a validated local client with a callsign-SSID of
WA7RGO-10, it will drop all packets from WA7RGO-10 which come in through
some other socket.

Each APRS station needs its own callsign-SSID.

- Hessu

[Rusty K7RMO]

Hessu, Okay, thank you, we will find another way to do it.

Rusty, K7RMO

[Nosey Nick VA3NNW]

I understand SSIDs have to be numeric (and have a very finite maximum) "on the air", but on the APRS-IS internet side there's no such limit? Surely you could give each one a unique 2-letter SSID? WA7RGO-AA, WA7RGO-EF, WA7RGO-PQ, WA7RGO-ZZ?

Quite apart from the loop-control issues already mentioned, this would make diagnosis easier too - if one of them appears to be being abused, or sending corrupt packets into the system or whatever, surely you would like to know which one?

73, Nick VA3NNW

[Lynn W Deffenbaugh (Mr)]

I considered making the same suggestion for alpha-numeric -SSIDs which are compatible with the APRS-IS, but realized that if they're running an IGate, they'd still likely want to advertise its presence on the RF side which the alpha-numeric solution does not support.

The only solution I can come up with is contacting local amateur radio clubs that might be within the target service area and use -1 through -15 of those various club callsigns for the IGates.  That would still preserve the base callsign (suppressed -0 SSID) for the club's use.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

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[Heikki Hannikainen]

The suggestion is good. The original post started with:

"The Amateur Radio Group of Oregon is planning to install multiple
receive-only IGates"

Which kind of implies no transmission on RF. If there's a need to announce
their positions on RF by one transmit-capable iGate, it could transmit
APRS Objects having the same names (alphanumeric SSID, WA7RGO-A0 to -A9,
-B0 to -B9...).

> https://groups.google.com/d/msgid/aprsfi/6a6b3148-228e-7138-d405-5d377c3d6f8d%40gmail.com.
>
>

- Hessu

[Bob Poortinga]

If they are receive only, why not use place names or tactical names as the APRS "callsign." This is done quite commonly. Take a look at the mountain top digis in Colorado as an example.

Bob W9IZ

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[Rusty K7RMO]

To everyone that has replied to my question, thank you! We will be considering all of your suggestions.

Rusty, K7RMO