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<font size="2"><font face="Arial,sans-serif">It is now becoming
apparent to me, based on several emails I have received since the
release of the new updated APRS symbol sets, that many people think the
APRS symbols are actually transmittted as tiny graphics. <br>
<br>
THEY AREN'T ! ! <br>
<br>
All that gets transmitted is a single alphanumeric ASCII character that
represents a given symbol POSITION in the APRS symbol list, not the
array of colored pixels itself. A second single ASCII character ( "/"
or "\") determines if the symbol is selected from the primary or
secondary set of about 90 symbols each.<br>
<br>
You can see the relationship between the alphanumeric codes and the
symbols they are supposed to represent, on my web site at:<br>
<a class="moz-txt-link-freetext" href="http://members.aol.com/wa8lmf/aprs/APRS_symbols.htm">http://members.aol.com/wa8lmf/aprs/APRS_symbols.htm</a> <br>
<br>
(A version of this reference chart, in GIF image format, is also in
each of the downloadable symbol set zip file archives on my site.)<br>
<br>
<br>
[[[[[ SINGLE MOST IMPORTANT FACT HERE ]]]]]<br>
What the receiving station sees is determined entirely by what icon
(symbol) happens to be in that particular cell IN HIS COPY of the
symbol grid. You CANNOT force another station to see a given symbol by
merely changing YOUR set of symbols.<br>
<br>
<br>
Over the years, many changes and additions have been made to the symbol
set. Most importantly, some symbols have been moved from the primary to
the secondary symbol set. The reason is that some symbols in the
secondary set can be overlaid with a letter or number of your choice;
the symbols in the primary set cannot. The cells in the text grid on
my website that are highlighted in yellow indicate overlayable symbol
positions in the secondary symbol set.<br>
<br>
For example, the green DIGI star in the primary set has an unchangable
"D" in a white circle as part of it's graphic design. The solid green
star in the secondary set is intended to be overlaid with a letter or
number of your choice to indicate digipeater capabilities. For
example, "N" would denote WIDEn-N capabilities, "R" = simple
RELAY-only, "U" = UIdigi-based digipeater, etc.<br>
<br>
Note that not all APRS applications properly handle the overlay
characters. On some programs you will only see the base symbol from
the secondary set but not the overlaid letter or number. For example,
UI-View properly renders the overlays, but the UI-Point add-on for
MapPoint does not. <br>
<br>
UIview's author (G4IDE - SK) unwittingly added to this confusion by the
usage of "No. Symbol" and "No Symbol" in symbols.txt, the file that
determines the text description of symbols that you see when choosing a
symbol and that you see in the "Stations Heard" list.<br>
<br>
"No. Symbol" means "Numbered Symbol" ; i.e. Overlayable<br>
<br>
"No Symbol" means "Unassigned Symbol"; i.e. this cell has nothing in it.<br>
<br>
The shelter symbol (red building outline - lower-case z) is a special
case. For a long time, the shelter symbol was located in the primary
set. It was then reassigned to the same position in the secondary set
so that it can be overlaid with letters or numbers. The position in the
primary set then officially became a "NO SYMBOL" slot. <br>
<br>
( In all other cases, a symbol moved from the primary to the secondary
set was replaced by a new, unrelated symbol in the primary set. )<br>
<br>
The result is that if you chose the "SHELTER" code in UIview (from the
secondary set) , it would show up as NO SYMBOL in APRSplus, WinAPRS and
on FINDU which still assumed the symbol was in the primary set.<br>
Conversely, if a user of APRSplus or WinAPRS would send "SHELTER"
from their (outdated) list it would be coded as being in the primary
set and show up on FINDU as such, but as NO SYMBOL on the more current
UIVIEW.<br>
<br>
<br>
<br>
1) FINDU is now using the updated Rev G character set which conforms
to the latest APRS symbol definitions and assignments. <br>
<br>
2) If you choose to use the new symbols "Mobile Satellite Station",
"Wheelchair", "Snowmobile", "Logged On" or "Laptop" in the primary set,
or "Construction Zone" (Steamshovel) or "SUV" from the secondary set,
it will show as such on FINDU, but people with outdated older versions
of the symbol sets are going to see "NO SYMBOL" on their maps. <br>
<br>
3) THERE IS NOTHING I CAN DO ABOUT THIS MESS except urge everyone to
update to the current symbol set as soon as possibile.<br>
<br>
<br>
In the interest of reverse compatibility (since the primary set
position corresponding to the current position of "SHELTER" in the
secondary set is now technically UNASSIGNED), I chose to place the
shelter symbol in BOTH the primary AND secondary sets of Rev G
symbols. I will leave the symbol there until a new meaning and symbol
gets assigned to the primary cell. <br>
This will make YOUR copy of UIview, APRSplus, etc., display the
shelter symbol ON RECEIVE no matter which code (primary or secondary)
the other party sends, but you can't make a single TRANSMISSION that
will show correctly on everyone else's display, since you can't
TRANSMIT both the primary and secondary codes at the same time. <br>
<br>
Note that I have filled all other "unassigned" ("NO SYMBOL") slots in
the symbol sets with a crosshairs symbol (rather than the old tiny text
message "NO SYMBOL") so that posits transmitted by others with invalid,
out-of-date or incorrect codes will at least produce a usable position
indication on your own maps.<br>
<br>
(In all other update cases, a symbol moved from the primary to the
secondary set was replaced by a new, unrelated one in the primary set.
No position, other than "SHELTER", was left vacant as a result of a
symbol re-assignment.)<br>
<br>
For example in the early days, upper-case letter "T" in the primary
set caused the symbol "Thunderstorm" to be displayed. Some time ago,
this symbol was moved to the same position in the secondary set. The
empty slot in the primary slot was reassigned to "SSTV". However, many
APRS software authors (and FINDU.COM) continued to use the outdated
symbol set. As a result, I would select the "SSTV" symbol on my Kenwood
D700 when I run my "Mobile SSTV LiveCAM", but people viewing my posit
on findu would see a moving thundercloud instead. Now that the findu
symbol set is updated and current, visitors to findu will correctly see
the SSTV symbol (TV monitor with a smile face in it). <br>
<br>
<br>
<br>
<br>
<br>
Stephen H. Smith wa8lmf (at) aol.com <br>
<br>
Home Page: <a class="moz-txt-link-freetext" href="http://wa8lmf.com">http://wa8lmf.com</a><br>
<br>
New/Updated "Rev G" APRS <a class="moz-txt-link-freetext" href="http://members.aol.com/wa8lmf/aprs">http://members.aol.com/wa8lmf/aprs</a><br>
Symbols Set for UI-View, <br>
UIpoint and APRSplus:<br>
<br>
<br>
<br>
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