[aprssig] Fixing AISat Digipeated Packets

Heikki Hannikainen hessu at hes.iki.fi
Fri Apr 19 15:42:07 EDT 2019

On Fri, 19 Apr 2019, Max Harper via aprssig wrote:

> As some of you know, AISat has some problems with digipeating and some/all igate software will not gate these
> packets. Robert MacHale KE6BLR has written some code to fix these packets for me and a few others. 
> My question is, should we be doing this? I know this is outside what an igate would normally do.

I'd vote "no":

- If gateway software starts modifying packets intentionally, there will 
easily be slightly different variants of the modifications done, which 
will cause slightly different duplicates of the packets to be present on 
the network. There are already too much problems with things like this 
happening on buggy igates which can't handle non-ASCII characters, or 
treat APRS packet contents as unicode (or some other encoding) strings as 
opposed to binary byte arrays/buffers.

- If there's a single piece of software that's doing something wrong on 
the network, that software (the satellite) should be fixed, instead of 
doing really ugly workarounds elsewhere.

- That would set a silly precedent.

If they are unable to fix and re-upload the software after launching a 
satellite, and can't be bothered to test the software on ground before 
launch, they should seriously consider their budgeting of money and time.

Satellite launches are so expensive (or valuable if you get a bargain 
price) that a liiittle bit of APRS network co-operation testing might be 
squeezed in the budget. Or a bootloader with firmware update support, 
even, as you will always have some bugs in there that you just might want 
to fix.

   - Hessu

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