APRS elevation issues

[Marty Glapa]

Any ideas on this analog APRS issue? I see an issue with elevation a while ago but see now resolution.

When I view GPS info on my Anytone 878 handheld screen the latitude, longitude and elevation are all correct regardless of where my location is. However, when I look at the data on aprs.fi, my elevation always shows anywhere from about 700 to 1,200 feet lower elevation than where I am, latitude and longitude are correct. I see other HAMs on aprs.fi using the same digipeater/ igate and their elevation is correct (so maybe not a network problem). Same problem when I travel and use digipeaters/igates in other geographic locations. Problem occurs no matter if I use a rubber duck or the antenna located on my vehicle. Doesn't matter what path setting I use. Doesn't matter if I am stationary or moving. I am on the latest firmware release for the radio, but I have had this issue with every previous firmware load. Doesn't matter if I set the radio to metric or imperial measurements. Radio is not beaconing a fixed location. Happens on every analog channel enabled for APRS and on a dedicated APRS channel I have on the radio. I have wiped the radio clean via hard reset and reloading of the code plug. I don't see a way to calibrate GPS settings, but per earlier, all GPS information displayed is correct per radio display screen. Adjusting APRS sending intervals has no impact.

It almost seems like the radio is sending the wrong altitude information even though GPS shows the correct information. 

Any ideas?

[Heikki Hannikainen]

On Sat, 11 Sep 2021, Marty Glapa wrote:

> Any ideas on this analog APRS issue? I see an issue with elevation a while ago but see now resolution.

First things first: There is no analog APRS. APRS is a digital protocol.
Some manufacturer apparently is confusing DMR or D-Star/DPRS with APRS and
somehow thinking DMR would be more digital than APRS. :)

> When I view GPS info on my Anytone 878 handheld screen the latitude,
> longitude and elevation are all correct regardless of where my location
> is. However, when I look at the data on aprs.fi, my elevation always
> shows anywhere from about 700 to 1,200 feet lower elevation than where I
> am, latitude and longitude are correct. I see other HAMs on aprs.fi
> using the same digipeater/ igate and their elevation is correct (so
> maybe not a network problem).

> It almost seems like the radio is sending the wrong altitude information
> even though GPS shows the correct information. 

By your description it seems very likely that the radio is encoding the
altitude wrong, and you seem to have figured it out correctly. aprs.fi is
just displaying what the radio is sending. You can check the raw packets
and what they contain after decoding here, just look up your callsign and
compare the decoded data with what you're expecting to see:
https://aprs.fi/?c=raw&call=&limit=25&view=decoded

Please contact the support department of the manufacturer, or the support
forum of that radio. This aprs.fi forum is for discussing aprs.fi (the web
site, and the iPhone/iPad app). This forum is not for general APRS topics
or support/issues of hardware and software from other vendors such as
Anytone.

I normally outright reject all posts in moderation phase when
device-specific configuration issues or bugs are posted (there are quite a
few coming in), but I made the exception to get a chance to point this
out.

- Hessu

[Marty Glapa]

Determined by working with several others who encounter the same problem, and the vendor, that indeed this is a radio firmware problem.

Marty

--
You received this message because you are subscribed to the Google Groups "aprs.fi" group.
To unsubscribe from this group and stop receiving emails from it, send an email to aprsfi+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/aprsfi/alpine.DEB.2.21.2109141032070.2043%40jazz2.he.fi.