[aprssig] Object Tip o' the Day
John Gorkos
jgorkos at gmail.com
Fri Jun 10 15:13:58 EDT 2011
If you're one of the remarkably helpful people injecting Objects into the APRS
network, PLEASE follow the spec.
Just as an example, here's an anonymized beacon that's being injected into the
network:
NXXXX-10>BEACON,qAR,W8DF-5:;147.00+*111111z4212.85N/08536.57WrKARC RPTR PL94.8
The object name is "147.00+". However, according to the Spec, Chapter 11 for
"Object Report Format -- with Lat/Long position", the Object name is a
mandatory 9 characters long. So, on both my parsers and the Perl parsers,
this beacon blows up, nothing makes it to the maps, and puzzled looks abound.
I'm not sure what the firmware parsers do (Argent, Kenwood, Yaesu, etc) with a
non-spec-following packet.
Just wanted to pass this along. I've sent three helpful emails to beacon-
broadcasters today because I believe beacons are the Right Thing, but they
need to be done the Right Way.
Also, while I'm on my soapbox..
<rant>
WTH is wrong with people and coordinates and APRS? Really, is it that hard?
Let's play "Find what's wrong with these positions":
@101325z3384.86N/11817.17W_196/000g002t060P000h83b10136.wview_5_18_6
Nice try, but you can't have a "Minutes" value in your Latitude over 60.
@101325z43.233N/77.1W_000/004g003t066P000h54b10177.wview_5_19_0
This is bafflingly wrong. 43.233N 77.1W isn't the right format.
Both of these first two came from "wview" software, it seems. Perhaps the
author could do some verification?
@101323z0000.00N/00000.00_065/000g002t066P000p000r000b0125h57.PCWS2.93.19E60
Not only do you not know where you are, you tell the world in the wrong
format. It doesn't matter if you're parked on the Prime Meridian, you have to
give me an E or a W to fit the spec.
!4520.34N/1620.20E#9A7S-10 APRS4R IGATE
Fail on Longitude. Need 5 digits before the decimal. At least we know this
guy is East of the prime meridian.
!2111,72N/101136.09W#PHG47506/ http://craeg.remtronic.com
Comma, period, they're all pretty much the same, right? Not too sure about
the 6 digits in the Longitude, either. Perhaps there's some wraparound effect.
;146.920- *111111Z4328.18N/0854.76WrT094 R20m Fremont Rptr
This one gets the "SO CLOSE" award. He actually space-padded the object name
(see top of message, before I started ranting), then managed to dork up the
Longitude with 4 instead of 5 digits left of the decimal.
!494713N/00917.48E#APRSsop DH4FAJ
If my wife missed periods the way hams do, I'd need three jobs to pay for all
my kids.
!4158.36N/08749.53W
=3954.22N/07518.27W
Short, sweet, and almost missing the point. The "/" is the SYMBOL TABLE, the
missing character at the end of the message would tell me what symbol to
use...
=5120.94N/0.01W/www.nehr.org.uk {UIV32}
Another guy withing spitting distance of the Prime Meridian, and unwilling to
spend the zeros to tell the rest of us about it.
!5000.01/01208.22E# (APRS DIGI Marktredwitz) 1
We could ASSUME North here on the latitude, but the spec doesn't allow for
that.
; 146.760-a*000000z3802.17NS08424.17W#PHGphgd/R,SSn,Wn BARS Digi in Lexington,
KY
Another object that was SO CLOSE. Corrrectly padded to 9 characters, then the
"S" in place of the symbol table. Note: this COULD be correct. Someone tell
me if it is. Is this the correct format for an overlay icon?
All of these packets came across APRS-IS in the space of about 30 seconds.
take a gander here:
http://aprs.fi/stats/daily
at the "Number of packets received from APRS-IS per second" graph. See that
red fuzz at the bottom? That's ignorance and laziness manifesting itself in
our network. This is the place to be involved. This is where people like the
ones on this list can stand up and say "Stop polluting our ether with bad
packets." Software developers - put simple checks in place to keep your users
from spewing garbage into the spectrum. Use APRS.FI and look at the stations
in your neighborhood in RAW PACKET mode. If you see red, do a little
elmering.
</rant>
John Gorkos
AB0OO
More information about the aprssig
mailing list