APRS. No Altitude reporting

My teammate and long time friend Danny Kight has been running his APRS for a year or so. I originally programmed this for him. It has never shown altitude. I assumed I forgot to check the 'send altitude'. Well I read the configuration today and much to my surprise, send altitude was checked. Now scratching my head. Any ideas what might be causing this?

Mike,

I would put the GPS at the top of the suspect list. Can you try a different GPS? Is Danny using a standalone GPS or getting NMEA data from something with a shared data stream?

You might also try disabling MIC-E so the actual data string will be transmitted. Look at my raw data to see the unencoded NMEA data being transmitted:

http://aprs.fi/?c=raw&call=N399SB

Without the encrypted MIC-E symbols you can pick out the data in each packet. I disabled MIC-E so it would be easier for SAR to see what my tracker is transmitting.

hmm. Interesting. I hooked it up to my spare GPS and the altitude is working. I believe you have nailed it. He is getting GPS from his GRT NMEA out. That explains it. Ill get with GRT and find out why its not sending alt in their sentence.

Kahuna said:

hmm. Interesting. I hooked it up to my spare GPS and the altitude is working. I believe you have nailed it. He is getting GPS from his GRT NMEA out. That explains it. Ill get with GRT and find out why its not sending alt in their sentence.

Click to expand...

GRT may have a menu in their setup that allows you to select the sentences being transmitted.

My iFly 700 has that feature. I just set it where it sends everything.

PGRMZ

I'm pretty sure it's the $PGRMZ sentence you need for altitude reporting on APRS.

Neil

Only Send Valid

Not directly related to the missing altitude but "Only Send Valid", a checkbox near the upper right of the TinyTrak3 configuration screen, should also be checked. Otherwise the tracker can send a packet before the GPS has acquired satellites, resulting in a Lat/Long of 0/0 (out in the middle of the ocean).

Sure, the bogus packet is filtered out by most web servers but not before it's transmitted on RF and on the APRS-IS causing needless congestion.

73,
Joe, K7JD