TMD710 APRS Problems
John McNelly <jkailimcnelly@...>
I have an Arduino set up with a TNC for APRS position reporting and messaging. I am getting messages that look like this:
I am trying to have this interpreted as a mobile station with a balloon icon, GPS coordinates 2400.00N, 12100.00E. The F= and A= stuff is GPS fix and altitude info that I am appending to the end of the packet as the status.
However, when I view my packets on the D710 station list, it shows up as “COMPRESS” and looks like this:http://i.imgur.com/jYlCnlU.jpg
Why isn’t the correct symbol displayed, and how can I get the D710 to show me the GPS coordinates of my tracker? I am trying to use this to track a weather balloon we are launching for school on Tuesday, and the D710 is my best hope of decoding the APRS packets to find out the balloon’s location and track it down. I could always read packets off of P.MON, but with heavy APRS traffic it would make things much more difficult than if the coordinates were just displayed on the station list.
Good morning John KK6NQK, all symbol strings transmitted have to be interpreted by the firmware in the TNC that displays it. You can check Kenwoods site about that at http://www.kenwood.com/i/products/info/amateur/software_download.htmltoggle quoted messageShow quoted text
As the Kenwood TMD710A TNC is much different than the TMD700A that I own, I am not sure if there are menu options to deal with it, though I wouldnt expect it. Several other discussion forums can probably nail this on down for you, especially the first two listed below.
Bob Bruninga wb4apr@... is the source for all things related to APRS as he started APRS from the beginning. He also has a ton of information on a web site at: http://www.aprs.org/
Good luck and let us know what you ended up doing to resolve your issue.
73 from Bill - WD8ARZ
WD8ARZ-7 HT TH-D7AG
WD8ARZ-9 Mobile TM-D700AG
WD8ARZ-10 Android Smart Phone - APRSdroid and U2APRS
APRS Viewer on Android for displaying APRS stations only, no beacon / transmitting.
On 11/16/2014 11:14 PM, John McNelly jkailimcnelly@... [TMD700A] wrote:
Your message format is not correct. This is not a Kenwood radio issue; it is a general APRS issue.
Your use of "@" as the first character indicates a data type of "Position with timestamp (with APRS messaging)". You did not include a timestamp, so any receiver will not understand the formatting of your message, and will misinterpret where your symbol characters are in the message.
You have 4 options to correct this:
1. Replace the "@" in your message with "=", which indicates "Position without timestamp (with APRS messaging) - This is probably not what you want, because your Arduino beacon probably does not support APRS messaging.
2. Add a timestamp before your lat/long. - This is probably not what you want, since you are still advertising messaging capability.
3. Add a timestamp, and replace your "@" with "/". This would indicate the time of the beacon and indicate no messaging capability. This is probably closer to what you want, although you'd have to set up a clock in your Arduino, which can be challenging.
4. Replace the "@" in your message with "!". This is your easiest option. This will indicate no messaging and no timestamp. Everything else is (mostly) correct.
The standard for Altitude with /A= is 6 digits for altitude in feet, so /A=001000 for 1000'.
You may find it enlightening to read the APRS spec, if you're writing your own APRS-generating code.