Scan speed on 536HP vs signal strength

I just noticed something very unusual on both of my 536HPs. Tonight, just for the fun of it, I decided to run only the stock antenna on both and see what I could pick up. I compared this with a Diamond RH77CA antenna on both (using 90 degree connectors). I set my FLs for stronger local stations here, including LAPD (P25 conventional), LA Sheriff, CHP, and other local LE (Whittier, Downey, Long Beach).
Although the RH77CA was better, I noticed that as both scanners passed through the LAPD conventional P25 system using either the stock or RH77CA antennas, they seemed to hang up specifically on the P25 system for about 4-5 secs on each department, then would scan the other analog systems fine. They repeatedly would hang up when scanning through LAPD P25. My hold times are set to 0 sec on all systems.
Now, when I put myoutside antennas on, with obviously stronger signal levels, there is no hang-up on the LAPD P25, scanning speed seems to be fine, Just whizzes through the LAPD system fine with no hang up, the same as other analog systems. I replicated this behavior on both of my 536HPs.
I bring this issue up because I know some have mentioned slower scanning speeds with the x36HPs. From my inadvertent findings tonight, this seems like it may be related to signal input level. Why is this happening? There is no P25 waiting time, as there is for a Motorola combined digital/analog system, so this should not be an issue.
It seems that with weaker signal input, the scanner is hanging onto to the P25 conventional channels searching for something. Is this typical behavior for a scanner, or have I inadvertently found something unusual. Any advice is appreciated.

Steve AA6IO

Happens on my x96's as well.

Sent from my Z750C using Tapatalk

Same thing with my 436HP, yet I don't have to have any P25 conventional channels in a favorites group when this happens. All channels have a PL or DPL assigned - none with carrier squelch.

I clone one favorite group and only changed the quick key, scanning the exact group of freqs in two separate groups. The same thing happens, it hangs on one or the other. No rhyme or reason.

Have also noticed this on the 396XT, but not to the extent it's happening with the 436HP.

If these P25 systems are trunk systems, what you are seeing is the scanner evaluating the control channel (or channels in range). Judging by your 4-5 seconds I would say it's evaluating 4 or 5 control channels.

If they are conventional, it may be that other signals are on the same channels and the scanner has to determine if the signal is a P25 signal or not. That too takes time.

None of these are trunk systems, and there are no other strong adjacent channels involved. The LAPD has these channels to themselves. The LAPD P25 has a NAC of 466, but most of the other conventional analogs I mentioned also have CTCSS. There is something about the digital signals, that when the strength is low, the scanner seems to hang. Seems like some others (posts above) are experiencing some variety of this, but not necessarily related to the digital signals. If happening with XTs as mentioned by mule1075, then not unique to x36HPs, but it seems pretty pronounced.
Anyway, the minute I put an antenna on that brings the signal strength up, bam, no more hang-up. No CCs involved at all with these systems, and no real adjacent interference.

Steve AA6IO

Sounds like maybe local interference - perhaps from a PC? Another possibility is that it is barely receiving the signal, but not enough to decode reliably.

OP, need to look into if P25 transmits an "end of transmission" byte. I suspect this may be the case and the 536 (and others) are not decoding the "end of transmission" data and confusing the scanner into thinking there is still a transmission taking place when the signal is weak.

I know PL and DPL's have this end of transmission when radio is un keyed.

XTS3000
That's a good thought. That could well account for what I am experiencing. Since my last post on this thread, I tried the same experiment (antenna-signal strength) with other P25 stations and did note similar findings. Indeed, it could be that the scanner is searching for that end code and not finding it.
Steve AA6IO

EOT only affects the duration after receiving signals. As I read the OP, it appeared you were talking about scan speed, not delay after transmissions. If you are talking strictly scan speed, EOT would not apply.

Voyager,
You're right. I am not talking about delay after transmissions, but only about scan speed.
Even when there were no P25 signals in any particular scan pass, the speed was slow. Well, still a mystery.
Steve