Strange D* problem when tethering MMDVM to iPhoneSE

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w9mt
Posts: 23
Joined: Mon Jul 15, 2019 2:40 pm

Strange D* problem when tethering MMDVM to iPhoneSE

Post by w9mt »

I have successfully built several MMDVM's currently running Pi-Star 4.1.5. They work great without issue on DMR and Fusion at home and in my vehicle.

I also have three MMDVM's that I rotate for use for D-Star at home and in my vehicle whilst mobile (one at a time with 2 spares). Two are standard Chinese MMDVM kits in the black metal boxes with a 0.96" monocolor OLED3 LCD. One is an N5BOC MMDVM with an identical LCD. All three of the D-Star configured units exhibit the same problem when used with cellular data via the iPhoneSE.

ALL of my D* MMDVM's work properly, connecting to and using ANY reflector on my home WiFi network. As such, I find it hard to believe the problem lies within the Pi-Star app.

Here is how the problem manifests itself:

I use an original iPhoneSE (4G LTE on AT&T, which is on a GSM TDMA derived infrastructure) for tethering cellular data to my MMDVM's. I can connect any of my D-Star configured MMDVM's to most reflectors with the voice prompt indicating "Connected to REFnnnn", where nnnn is the reflector ID. The problem lies in reflectors in the range of REF030 A, B, or C through REF033 A thru D. In that narrow range, the female prompt voice says "Connecting to REF03nn" and never actually connects. Anywhere else everything works fine when connecting to other reflectors. I remember a time where connections to the very popular REF030C ragchew reflector did work, but more than a year ago, 30-Charlie stopped connecting via iPhoneSE tethering. Currently, none of my D* MMDVM's ever successfully connect to 30-Charlie at all via the iPhone.

I tried reverting back to 2019's 3.4.17 load on an SDHC chip, but that didn't fix this issue.

Where do I look for a cause to this problem? I find this very weird, as I have never seen this issue with any other reflectors other than this narrow range that includes 30-Charlie. I have no other problems with QSO's dropping on any other reflectors, either.

So what's the guess? Is this an iPhoneSE problem or more likely an AT&T infrastructure issue? If so, how should I phrase my questions when I call tech support?

Any light that can be shined on this strange issue would be most appreciated.

73, and many thanks...Tony (W9MT)
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