TD-H3 GMRS observation: transmit issue with/without privacy code

[Imply4907]

Good day!

I apologize if this question has been asked/answered -- I did some searching and wasn't able to find anything specific to this, yet I don't believe I'm the first person to encounter this.

TLDR; I can't transmit on a second similar frequency channel with or without a "privacy code"

I know "privacy code" usage isn't private. I'm using it as a general term for using DCS/CTCSS codes to reduce hearing unwanted signals.

Equipment: I have a TIDRADIO TD-H3 (HAM version) running in GMRS mode

• The firmware version is GMRS_240817
• I can and have programmed it on Odmaster or CHIRP
• I can do some limited work on the HT itself
• I just got it this week, so I'm still a little new (Jan. 15 2025)

Intent: My younger children have some FRS radios where I used FRS/GMRS Channel 1 plus a "privacy code" to (a) reduce some of the distraction from area GMRS/FRS users (b) potentially reduce the possibility that their ears might hear something inappropriate. I'd still like to be able to switch to a regular "privacy code"-free channel when I'm away.
I want to talk to communicate with them from my TD-H3.

Situation: I can't transmit out on higher of the TD-HD3's two channels if I have a mixture of privacy code and non-privacy code for the same frequency. The radio prevents transmitting on the higher channel of the same simplex frequency. Example: If I use GMRS freq. 1 and put the "privacy code" on HT radio channel 1. I then use a "privacy code" free GMRS freq. 1 on the HT radio's channel 31. I can transmit out and be heard on the FRS radio when I use HT channel 1, but can't actually transmit (and hear a rejection tone) when I use the HT radios channel 31 on the same frequency. If I make HT channel 1 clear of codes and make HT channel 31 the same frequency as channel 1, but use a "privacy code", the radio blocked me from transmitting on channel 31.

I discovered this after several hours of troubleshooting and hand-wringing. It didn't matter whether I used DCS or CTCSS. I then tried using "privacy code" on the lower radio channel and put the privacy free* on the greater channel and saw I could use a privacy code successfully. What's a little weird is that I have a repeater setup with a CT tone and the radio will transmit fine.

I don't know if this is by design or a limitation of the TD-H3 and similar firmware. For all I know, it might be a general phenomenon of TIDRADIO products.

Comparison: I have a brand new pair of Baofeng 5RMs that I would like to see if they exhibit the same phenomenon, but there are issues with the programming over the cable preventing me from quickly programming them. Maybe I'll figure out how to program them on the keypad. Observation: I get the feeling that Baofeng and TIDRADIO are basically the same manufacturer but simply different brands.

Kind regards,

Jim
Woodleaf, NC USA
WSGP797

Edited 18 hours ago by Imply4907
clarification of the "intent" section. Edit 2: improved title. Edit 3: Corrected typo in firmware version.

[Imply4907]

What I described appears to be a limitation of the TD-H3 and not the 5RM as I just tested a similar scenario on the Baofeng.

[WRTC928]

20 hours ago, Imply4907 said:

What I described appears to be a limitation of the TD-H3 and not the 5RM as I just tested a similar scenario on the Baofeng.

I was about to tell you that I haven't had this problem on the 5RM. Is the TD-H3 a GMRS-specific radio? Sometimes the manufacturers of GMRS radios fail to consider the possibility that you might want more than one channel or more than one repeater on the same frequency.

[Imply4907]

It's the HAM version but its running in GMRS mode. I only have my GMRS license at this time.

[Imply4907]

Update: I put an inquiry in to the nice people at TIDRADIO.