[aprssig] "special icon" and overlays

[Robert Bruninga]

> I've never used overlays...
> could you give me a few examples...
> ... what I would program into my D7g 
> or my D710 to display a couple of icons 
> with overlays...  Would /[  and 
> H[ give me the hiker symbol as I understand it?

Back 10 years ago when the D7 was designed, many people were
using WinAPRS and it had a limitation which only allowed overlay
characters on a few dsignated symbols.  Back then, the D7 also
then only allowed overlays on those few symbols.  The D700
followed suit.  In 2006/7 we realized that few people are using
WinAPRS, so we can expand future APRS and allow overlay
characters on all symbols.

But I am not sure if that got into the D710 or not (it will in
the future).

So, anyway, to see how they work, simply choose a symbol that
already allows an overlay.  You can see them in the
www.aprs.org/aprs11/symbolsX.txt file as the ones with a # in
the ALTERNATE or SECONDARY table listings...

Kenwood solved the problem of the graphics by placing the
overlay character to the upper left of the symbol instead of
trying to overlay it right on top of the complex graphics.

Bob, Wb4APR