Trunking Activity Indicators

[ofd8001]

Well, I'm either doing something wrong, or haven't gotten something set correctly.

I'm listening to a P25 trunked system, and have the display mode set to where it displays the trunking activity indicators. I'm pretty sure I have all the frequencies programmed and NOT just the control channels.

When I hold on the control channel, I see only one bar pop up, even though I'm sure more than one repeater is active. What I am seeing are the names of the talkgroups that appear to be used. The way I'm understanding it, is that if for example, 5 frequencies are in use, then there should be five bars popped up. However the only one that is up is the second one from the left, which I know is the control channel.

Any thoughts??

Thanks!

 

[del1964]

I had the same "What the heck!?" moment you're talking about and so I posted a similar question/concern a while back and the way I understand it is it doesn't work on Motorola systems such as what Indiana has......or something like that. Anyway, bottom line is I can confirm 100% that it does not work where I live on the Indiana SAFE-T system and I really really really wish it did. That would be at the top of my list on a firmware upgrade and also the ability to turn on or off the ability to scan and hold on ENC communications.....Mr Upman?

 

[KE4ZNR]

True P25 systems use Control Channel Only for trunking. So even if you program in all of the system frequencies the radio is only going to use (and see) the Control Channel Freqs.
So the trunking indicator is useless on p25 systems.
It was a good feature before CC only scanning came around but has
now been rendered obsolete.
Marshall KE4ZNR

 

[del1964]

The thing I don't understand is if 4 agencies are active on the same site, they all have to be on different frequencies....they couldn't all use just the control channel frequency. When I watch what is displayed as far as frequency goes, a lot of times it is not the control channel frequency. That's where the "not understanding" part comes in on why we can't see all the activity on a site. Looks like you should be able to see Fire is using this freq and EMS is using that freq and the PD is using yet another freq. and indicators would blink showing those three frequencies in use at the same time.....in other words also you would be able to see that you're missing out on some conversations because you'd know more people are active and then you could turn the knob on top and move over to a different talkgroup if you wanted...

 

[KE4ZNR]

The thing I don't understand is if 4 agencies are active on the same site, they all have to be on different frequencies....they couldn't all use just the control channel frequency.

No one "uses" the control channel. All radios on the system MONITOR the control channel for instructions on which frequencies/channels to use. That is how a Motorola system works. An actual two way radio on a Motorola system does NOT have all the voice channels programmed into it. An actual two way radio only has the Control channels it needs to monitor programmed into it and tunes the radio based off the info it gets of the control channel it is currently monitoring.
The days of needing to program all the frequencies for a Moto site into a scanner are long gone. Wasted space as the scanner only needs the control channels programmed in.
The trunked activity indicator was a cool feature in it's day but
Control Channel only trunking rendered it obsolete.
Marshall KE4ZNR

 

[ofd8001]

Well, I'm glad I'm not crazy.

I was more or less interested in seeing how many frequencies were being used on the system I monitor at any given time, just to see the system loading.

As far as programming a control channel goes, yes it takes up less space/resources on a scanner. On the other hand, there are no guarantees that the radio system people won't change a control channel at some point for some reason or another.

Plus if you have a "Fail Soft" situation go on, having all of the frequencies in your scanner is a good thing. That's so you can re-program the scanner as a convention system while it is in fault, without having to look them up in the database.

 

[jackj]

The Control Channel is just used to coordinate the radios. All of the radios working off of the same tower will monitor the CC. If there is traffic for a Talk Group then the CC will broadcast a Talk Group ID and a voice channel for that TG to use. All of the radios in that TG will switch their voice over to that channel while continuing to monitor the data on the CC. Each tower will have one CC active at a time but may have several voice channels active at the same time. The CC consists of both a receive and transmit frequency, just like the voice channels, and each radio will communicate with the CC from time to time. The system operates similarly to a cellular telephone service.

I hope this helps.

 

[KE4ZNR]

Well, I'm glad I'm not crazy.

Not at all.

I was more or less interested in seeing how many frequencies were being used on the system I monitor at any given time, just to see the system loading.

I understand and a part of me misses the old activity indicators as well.
But a bigger part of me appreciates the UID/RID display that now takes up that space on my 396XT/996XT.

As far as programming a control channel goes, yes it takes up less space/resources on a scanner. On the other hand, there are no guarantees that the radio system people won't change a control channel at some point for some reason or another.

I agree. However with Programs like Trunk88 and Unitrunker that can show all CCs and all Alternate CCs a majority of systems have their CCs and Alt CCs mapped out in the database. So it is a minuscule risk with the data available through various sources.

Plus if you have a "Fail Soft" situation go on, having all of the frequencies in your scanner is a good thing. That's so you can re-program the scanner as a convention system while it is in fault, without having to look them up in the database.

I strongly agree with the above. I know system admins don't like to hear the word "Failsoft" much less deal with it but it is something that needs to be considered and remembered. If nothing else with the extra memory space that todays radios allow us to have you can thankfully store the system in a couple of times: once as the actual trunked radio system and once as a conventional "Failsoft" non-trunked system.

Long story short: you raise some valid points above and I agree with alot of them.
Happy Monitoring
Marshall KE4ZNR