You are on to something here. Holding on the top bar kills scanning. I don't trust the second one entirely, either, but I could be wrong.
I have an ideal arrangement for testing or confirming any anomalies suspected among a certain small group of radios. I can run 4 radios at a time from a single antenna and report on the results of any testing that I might do.
If I temporarily, for testing purposes, setup 2 or more of my radios identically as to unlocked TRS's/TG's/Channel's etc., any differences in reception due to Tweeking a single radio, will show up instantly. This is due to my different radios being very well matched in their scanning/decoding abilities.
I have tried to duplicate the "Hold on the top bar" problem without success. Holding on the top bar, during an active transmission, or when all three bars are unlit (not highlighted in yellow) results in a continuation of well matched scanning compared to the other radios. At this time these "other" radios are a PSR-800 and a PSR-500.
In an earlier post, someone mentioned a "Motorola" TRS. Is this critical to the problem? Does the radio need to be scanning "other" TRS's at the same time as the one being tested? If so, does it also need to be a Motorola TRS? Would it make any difference if it was tested on an HP-1 or an HP-1 (E)?
Is a change of the CC by the TRS necessary to trigger the problem. If so, I'm not sure how often the TRS's in my area make such a change.
Nearly all of my radios are set up using multiple P-25 TRS's with nearly identical TRS's in each radio. This makes testing involving P-25 Systems very easy to perform. There is only one Motorola TRS that I have programmed into (at least a couple of) my radios.
If someone would give me VERY PRECISE instructions on how to setup my HP-1 for testing, I will try to match that set-up and report my results.
Like I mentioned earlier, using a single P-25 TRS (~8 departments, ~20 TG's) I can not get the HP-1 to stop scanning by holding on the top bar (turning it yellow). In my case (the testing so far) the radio is already holding on a single TRS, while scanning the Departments/TG's in that TRS. Tapping the top bar only turns it yellow, it is already "frozen" on that TRS.
Thanks
Rob