Interesting scan behavior

AA3RP
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Re: Interesting scan behavior

Post by AA3RP » Fri Apr 01, 2022 4:40 am

F1RMB wrote:
Fri Apr 01, 2022 1:31 am
Hi,

which key are you using to stop the scan, PTT ?

I just tried with the same conditions, and it worls. As soon as I press the PTT key, the scan stops on the current channel.
As Colin mentioned, you have a 30s window to stop the scan to be able to stay on the current channel, as you selected "Pause" scan mode.


Cheers.
---
Daniel
Most of the time I use the PTT to stop the scan. It is not stopping the scan that is the issue, but rather when the audio / carrier stops prior to the Pause time out it jumps to the next channel in the scan list and waits for the time out to finish. If you just wait the scan will start up.

I will try and explain an example: I have the scan running and it operates as you would expect. Now it comes on a repeater that is giving out its scheduled ID. This repeater does both Morse and voice for ID along with some small message, so it lasts apx 15 to 20 seconds. It finishes and the carrier and audio drop. The radio jumps to the next channel in the scan list. It stays on that next channel until the 30 second pause completes (apx 10 to 15 seconds) then the scan starts up and runs.

I have this happen on long repeater IDs and audio of operators using the repeaters.

The bottom line of this is occasionally when I go to respond I am NOT on the channel that paused the scan but rather the following channel in the listing. The result being I am calling out on the wrong channel.

This does not happen always and this is why I took some time to be sure of what was going on before posting about.

The best way I know of observing this is to have a zone of fairly active repeaters and start the scan during the busy time for them, which for me is during the morning and afternoon commutes as there are many mobiles that use the repeaters near me while going to and from work each day. I just watch the display and every so often I will see the scan stop on a dialogue or station ID and when the carrier drops it goes to the next channel in the zone / list and sits there until the 30 second pause completes. Trouble is that it does not do this every time, only once in awhile and I failed in coming up with a way to trigger this behavior every time.

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F1RMB
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Re: Interesting scan behavior

Post by F1RMB » Fri Apr 01, 2022 4:54 am

Hi,

Pause time is the maximum allowed time. If the carrier is goes away before this amount of time, it will continue scanning.
It would be crazy to have a pause time of 30s, using your settings, because of a kerchunk as it would make the firmware to stop 30s for almost nothing, and would render the scan really inefficient.


Cheers.
---
Daniel

AA3RP
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Re: Interesting scan behavior

Post by AA3RP » Fri Apr 01, 2022 4:56 am

VK3KYY wrote:
Fri Apr 01, 2022 2:34 am
I think I may have observed this for a multimode repeater, but its difficult to know for sure, because if so its a very intermittent problem
I agree it is difficult to know for sure. At first I thought it was just me hitting some button on the mic with my fingers or something like that. But over time and with the recent trip where I was scanning nearly full time on both days of travel to and from it became clear that there is something going on. Once back home I waited for the current Alpha release even though I finally figured out what was happening by having my MD9600 scan all day.

For me this is not a show stopper, but I thought it would be best you know about it.

I will try and get you the info on the HTs in a few days and am keeping track of which repeaters I see it jumping away from.

AA3RP
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Re: Interesting scan behavior

Post by AA3RP » Fri Apr 01, 2022 5:06 am

F1RMB wrote:
Fri Apr 01, 2022 4:54 am
Hi,

Pause time is the maximum allowed time. If the carrier is goes away before this amount of time, it will continue scanning.
It would be crazy to have a pause time of 30s, using your settings, because of a kerchunk as it would make the firmware to stop 30s for almost nothing, and would render the scan really inefficient.


Cheers.
---
Daniel
Your are correct it makes for 'inefficient' scan but I am not wanting an efficient scan. Since I can hear the radios in my shack room nearly every room of home I often run scan on my local repeaters just so I can hear if anyone I feel like chatting with comes on. Often it takes me a good 15 to 30 seconds to get to the shack room so I want the long pause.

The long pause and listing to people ragchew for 30 seconds is not an issue for me as I am doing other things around the home anyway and it does start scanning. The only real issues is when people ragchew for over 10 minutes or more then the scan stops every time on them regardless of the Pause delay setting.

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F1RMB
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Re: Interesting scan behavior

Post by F1RMB » Fri Apr 01, 2022 5:08 am

Hold on, I'm checking the code ;-)

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F1RMB
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Re: Interesting scan behavior

Post by F1RMB » Fri Apr 01, 2022 5:16 am

Okay,

So, no, if the scan stopped and the audio came out of the speaker, the 30s (in your case) timeout has started, whatever the carrier disappears and even reappears (that won't rearm the 30 seconds timer).


Cheers.
---
Daniel

VK3KYY
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Re: Interesting scan behavior

Post by VK3KYY » Fri Apr 01, 2022 5:21 am

Hi Daniel

I think my MD9600 is exhibiting this problem when scanning.

There is a local multimode repeater

The scan biefly stops on that channel, but its normally not transmitting DMR, I think its transmitting YSF, and I've noticed the scan holds briefly while the firmware checks whether the signal is DMR, and then the scan continues to the next channel, which has no signal, and then it changes to the next channel and then Pauses

So on my scan its pausing on the YSF channel +2 when there a signal on the YSF channel.

I don't knwo if it happens under any other conditions.

BTW. I'm not 100% sure the YSF channel is YSF, it may be some other digital mode.

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F1RMB
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Re: Interesting scan behavior

Post by F1RMB » Fri Apr 01, 2022 5:23 am

I think, accordingly to what you wrote, that sometimes the scan stop of a kerchunk (hence the 30s timeout starts), no traffic for X seconds, then some traffic appears, but the timer is still running, and that will reduce the "heard time", hence you can imagine the firmware has stopped only few seconds, instead of the 30s you defined.


Cheers.
---
Daniel

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F1RMB
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Re: Interesting scan behavior

Post by F1RMB » Fri Apr 01, 2022 5:27 am

Hi Roger,
VK3KYY wrote:
Fri Apr 01, 2022 5:21 am
Hi Daniel

I think my MD9600 is exhibiting this problem when scanning.

There is a local multimode repeater

The scan biefly stops on that channel, but its normally not transmitting DMR, I think its transmitting YSF, and I've noticed the scan holds briefly while the firmware checks whether the signal is DMR, and then the scan continues to the next channel, which has no signal, and then it changes to the next channel and then Pauses

So on my scan its pausing on the YSF channel +2 when there a signal on the YSF channel.

I don't knwo if it happens under any other conditions.

BTW. I'm not 100% sure the YSF channel is YSF, it may be some other digital mode.
I think it matches my previous post.
Pause mode stops for X seconds, whatever is happening in this time window, and if the sequence is "kerchunk + Xs of silence + audio", the sensed result will be the audio length time only.

I just checked the code, pause mode timer can't resume earlier.


Cheers.
---
Daniel

VK3KYY
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Re: Interesting scan behavior

Post by VK3KYY » Fri Apr 01, 2022 5:31 am

This is happening with a solid YSF signal on a channel set as DMR.

The scan holds briefly on the YSF channel until its not decoded as DMR, and then the scan moves to the next channel where it checks for signal, but there is no signal, so it goes to the next channel, where there is still no signal, however the scan then pauses for 30 seconds on that channel which never had any signal, except perhaps a lot of QRM.

But if there is no signal on the YSF channel, the scan does not stop, so I don't think the problem is high QRM

Looks like a race condition, or 2 independant timers etc

I can't easly listen to the channel it stops on, at the same time as scanning, because I only have 1 external antenna.

However, I listened for several minutes on that channel by stopping the scan, and there was no activity.

So I think the scan is pausing on a channel with no activity becuase (CHANNEL_NUM - 2) had a non-DMR signal.

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