[aprssig] Venting about malformed packets

Heikki Hannikainen hessu at hes.iki.fi
Mon Jul 31 05:34:02 EDT 2023

On Fri, 28 Jul 2023, John Gorkos wrote:

> I was just spending some quality time relearning Java while updating 
> JavAPRSLib (now with weather packet parsing!), and I just want to claw my 
> eyes out at the number of malformed packets that traverse APRS-IS.  By my 
> eyeball count, between 2 and 4% of all transmitted packets are malformed.
> Of those, almost all are "hand entered" station info, and most of those are 
> bad lat/lons (too many digits, not enough digits, etc). Just carelessness. 

I think the underlying reason is that hand-crafting valid APRS packets is 
really quite difficult, unless you're fairly tech-savvy and have some 
understanding of coordinate formats.  Most APRS end users do not have that 

I think all APRS devices and applications should provide an user interface 
or configuration tool which would just take in the source data 
(coordinates, symbol, comment text string) and convert it to a valid 
packet. Likewise for PHG: just have the user input the antenna height, 
gain, etc, and then generate the PHG string without having the user 
convert by hand.

When entering coordinates, the applications should allow coordinate input 
in both of the common formats (decimal degrees AND degrees+minutes). On 
computer/mobile apps and internet-connected web UIs, just show a map where 
the coordinates are landing, and allow to adjust the position on the map.

   - Hessu

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