[Bug]: T114 can't send messages longer than 47 chars

[adingbatponder]

Category

Other

Hardware

Heltec Mesh Node T114

Firmware Version

2.4.3.91d6612

Description

Messages above 47 characters cannot be sent. Other are reporting that the message length that causes failure to send is variable https://www.reddit.com/r/meshtastic/comments/1fhc47k/heltec_t114_message_sending_bugfault

Relevant log output

No response

[adingbatponder]

https://meshtastic.discourse.group/t/problems-with-heltec-t114/14489

[adingbatponder]

Does it forward packets normally or are certain length messages not forwarded?

[meshtastic-bot]

This issue has been mentioned on Meshtastic. There might be relevant details there:

https://meshtastic.discourse.group/t/t114-fails-to-send-messages-above-certain-length/14719/1

[GUVWAF]

Can you try setting a lower transmit power (e.g. 3 dBm) and see if the issue persists?

I'm trying to figure out if it's a hardware issue (e.g. unstable power supply or EMC issues) or something else.

[lupusworax]

Lowering the transmit power to 3 dbm did the trick! it transmitted for me from one T114 to another (DM), longfast.
3dbm --> success
5dbm-->success
7dbm--> success but slight delay
8dbm--> failure
10dbm-->failure
But even with the 3db setting I was not able to successfully send a max length/characters message.

[willfootwill]

exact same behaviour here - ok below 8db

[willfootwill]

I tried going back to earlier firmware 2.4.xxx, no improvement

[lupusworax]

I am on 2.5 most recent release. If this issue is hardware based its bad, really bad!! because how I see it now every T114 so far is affected.

[NeilMartin]

My T114 is running 2.4.2 and I just sent a 71 character message to LongFast. Received successfully on my T-Deck (2.4.2).

[lupusworax]

Also tested to send from my T114 ( stock 27dbm) to my Heltec V3 a much longer message then 71 (150) successfully 3 times out of 4. #longfast DM

[DTopp]

Today at 27dBm I can send around 60 character messages, up to 30 characters no problem after that I had to resend a couple of messages.

At 3dBm I'm managing to send 200 character messages (stopped there as I wasn't sure what the limit is) and they've been getting through no problem.

[aljaxus]

can send 144-char (base64 encoded, and 107-char decoded) messages with tx_power set to 5. (more info in reddit reply)
Same message was not reliably sent when having tx_power set to 27. Will test further and update this reply as I go.

[thebentern]

Thinking out loud... Given this symptom combined with some of the sporadic BLE issues, I wonder if we're looking at some hardware level issues with the LDO converter not being able to supply enough current to the MCU + peripherals under certain loads.

[lupusworax]

Would a big enough capacitor at the LDO be able to buffer that?