UHF mismatch?

[Cuppa]

Our Icom UHF in the car hasn't had a great deal of use, but has always worked perfectly when needed.

Our old hand held GME hand helds similarly have never been a problem. (But have only ever been used to communicate with each other)

Tested both out together this afternoon as we want to lend one of the hand helds to the friends we will be travelling with soon.

Result - When MrsTea talks to me from either of the hand helds, I can hear her loud & clear on the Icom in the car
When I talk to MrsTea - she can hear me, but only just *very* quiet - has to have the handheld right on her ear to hear anything - & yes the volume is fully turned up.

Calling from one of GME hand held to the other GME hand held - loud & clear both ways.

Also tested with a neighbour's Icom Hand held & our Icom unit in the car - Loud & clear both ways!

Any ideas as to why when calling either GME for our Icom in the the car reception on both GME hand helds is almost inaudible. Same on a variety of channels we tried.

The Icom unit in the car is an 80 channel unit & the two GME Handhelds are 40 channel & I'm thinking I might vaguely recollect reading somewhere that there is a bit of an incompatability which this can cause the problem we're having?

[PeeBee]

Have you checked the actual channel spacing list for the 40 - 80 channels? The difference is 12.5hz v 25hz. most of the changes are in the upper 40 channels and not that user frequented from what i can see.

Have you checked the earth points, being antenna and radio? Where are you standing relative to the vehicle antenna mounting, is the vehicle blocking the signal? Its frustrating this radio stuff for sure. Check for cracks in the antenna. Also, do you have something like a Celfi antenna of antenna in a close proximity to the UHF, even close to the UHF frequency. You can lose a hell of a lot of power via a short circuit path from one antenna to the next and nothing actually goes out the UHF stick

[Cuppa]

I just read the following with thanks to Mr Google. I think it explains it our situation. I have ascertained the neigbour's hand held is an 80 channel.

When using a 80 channel uhf it can be possible to communicate to someone using a 40 channel using the first 40 channels, or vice versa. However, due to the difference in band widths, the person on the 80 channel can come through quiet and be difficult to hear to the person using the 40 channel.

https://www.offroadaussie.com/whats-the-difference-between-a-40-channel-and-80-channel-uhf/

Bugger!