[aprssig] case sensitivity of NSWE in posit reports

Keith VE7GDH ve7gdh at rac.ca
Wed Dec 29 14:52:22 CST 2010

Bob WB4APR wrote...

> Yes, those two bits NSEW or "nsew" are the only two bits we
> have that are available for carrying additional info in an APRS
> packet that are backwards compatible with most existing systems.
> But they are NOT with UI-View...

That is strange. I just generated an object using lower case n and w in
the lat / long. UI-View didn't have any trouble displaying the object.
Just to give it a bit more of a workout, I changed the script so that
it generated a regular position report instead of an object. Again,
UI-View displayed it OK.

If anyone wants to look at the object and position report that I used,
the name of the object was 123456789. I originally used the same
name for the "callsign" for the position report. Just to cover all the
bases, I changed it to VE7GDH-13 and did it again. Ignore the few
syntax errors while I was fiddling with it. It still displayed OK in
UI-View with lower case n & w used in the lat / long. Another myth
bytes the dust. I don't know who started the rumour, but it doesn't
appear to be true.

> so until UI-View is replaced completely, we cannot use those bits.

With all due respect to authors who are designing APRS clients, this may
be a long time in coming. I can't see all UI-View users just giving the
program the heave ho en masse... at least not unless something in the
APRS spec is changed to make it incompatible. All other APRS clients
would have to be updated too, but at least if the authors of those clients
were still actively developing the program, that shouldn't be a problem.
A lot of hardware might have to be updated too, but many of them would
just require a firmware update. I know there may eventually be a compelling
reason to stop using UI-View, but it  would likely take a conscious effort
to change the spec in such a way to make this a requirement, and APRS
would likely be in pretty in chaos during the transition.

On the other hand, if we are going to have chaos, we could all just move
to OpenTRAC. It would give us everything that APRS does now, but with
almost unlimited expansion for additional symbols and new ideas. It would
be a major change, but sometimes major changes are needed. Either we
stick with what we have now, which includes UI-View, or we move
forward. It's amazing what has been done within the constraints of using
20+ year old hardware, and some newer equipment that has mostly had
to live within the same constraints of that 20+ year old equipment.

73 es cul - Keith VE7GDH
"I may be lost, but I know exactly where I am!"

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