Patched Channels

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gadgetmikey

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I was curious if anyone knows how the scanners are supposed to handle patches.

I was using a bearcat BCT15; this weekend for the car show they had Event 15 patched with our service talk group. If I put my scanner on just the event talk group I miss anything that dispatch and any units running on the service talk group say, and then when I select just the service talk group I miss anything from units on the Event channel. Even in scan mode it is irritating because the scan delay is waiting for a reply on one or the other.

Just curious if this is normal or if there is a setting that will make the scanner read the patch information. I guess I would think that if the channels were patched together they would work like the radios and being on either channel would also pick up the other.

I know Davis leaves a couple of there channels patched almost always so I was hoping that you guys could shed some light on this for me. I have also noticed similar things with multi selected talk groups.
 

theaton

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Are you saying that the two sides of the conversation are on different TGs, or different sites? If a patch included both sides then there would be no problem.

I don't know of a scanner capable of dealing with that. Maybe all you can do is set the delay to 0 so the scanner moves on and finds another active TG ASAP.

-Tim
 

gadgetmikey

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As I understand it what the trunked system does is streams out a constant notification on the data channel that tg A is patched with tg B. Then a radio on tg b knows that it also needs to follow all traffic on tg a.

I would have to assume this has been addressed before but I can't seem to did anything up.
 

qlajlu

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To go one step further, were the mobile units using the Service TG able to hear the mobile units using the Events TG when they keyed up and vice versa?
 

gadgetmikey

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There was no problem with the mobile units because there radios new what to do with the patch. More than anything I am suprised that todays scanners don't.
 

Junior1970

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I was in Logan this past weekend myself with the '66. I noticed the Cache TGs coming up on Logan Peak but I thought that Event 15 was patched to Logan Event 1 (153.8375?) It seemed so to me with my old PRO-2067. The PRO-95 (which is NOT as old and yes I ran the handheld as well as the mobile in the car, wouldn't do the Main Street Cruise without it ) had no trouble going quickly from back and forth from the VHF to the 800 patch. I'm not too familiar with the BCT-15 or most of the newer Unidens as of late so I really couldn't say yea or nay. I didn't see any Cache TGs pop up on Cal Mountain except the Event 15 patch.
 

gadgetmikey

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You are correct it was Event 16 that I was talking about.

They had 16 patched with our Service Channel and it is allready patched with the VHF service channel.

Then also patched Event 15 with the VHF Event 1 channel.

Davis patches 9408 and 9440 almost all the time, I assume so that if things get busy they can easily split them. I have noticed in unitrunker that units log in to both of them. If you guys were to hold on one of them I would expect that you would notice the same thing and you would have missed conversations between the two talk groups.

I would be curious if it is just the bearcat.

If I had know you had a car in it I would have watched for you. :)
 

bneilson

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I have never run into this issue before on a patched channel. I have see it where I can only hear one side of the conversation but that is related to multiple sites and affiliations.

I am curious, was the Scanner set to ignore status bits, do you know?
 

Junior1970

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You are correct it was Event 16 that I was talking about.They had 16 patched with our Service Channel and it is allready patched with the VHF service channel.Then also patched Event 15 with the VHF Event 1 channel.Davis patches 9408 and 9440 almost all the time, I assume so that if things get busy they can easily split them. I have noticed in unitrunker that units log in to both of them. If you guys were to hold on one of them I would expect that you would notice the same thing and you would have missed conversations between the two talk groups.I would be curious if it is just the bearcat.If I had know you had a car in it I would have watched for you. :)
It was the only blue '66 Chev Impala in the show with an Antennex 800 whip on the decklid using the clip on mount. At least that I know of. I've been coming up to the Cruise-In for nearly twenty years and 17 of those with the same car! It's always interesting to monitor during the Cruise-In and the fireworks at Romney Stadium usually the same week.
 

jim202

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I am not sure if I understand what your saying here. Normally when a "PATCH" is made on
a trunking system or for that fact, between multiple channels on VHF or UHF, you hear
all the conversations on which ever talkgroup or channel your monitoring. An example
of this is the Alexandria, VA trunking system. Frequently at night, the police and fire
dispatch talkgroups are tied together (patched). What comes out on the fire talkgroup
also comes out on the police talkgroup. Have had two radios going at the same time on
the different talkgroups and you can hear the slight delay, but the same conversations.

Patches can be made on just about any radio console being used by public safety dispatchers
today. It simply ties one channel or talkgroup to another. There is no way to have only
half the conversation be re-transmitted. The exception to this may be if there is some
sort of crazy repeater system being used or split channel operation is being used. The
California Highway Patrol sort of use this type of application. When a split channel is
being used, all you hear at times, is a slow beeping tone on the dispatcher channel
while the mobile is talking.

Jim



I was curious if anyone knows how the scanners are supposed to handle patches.

I was using a bearcat BCT15; this weekend for the car show they had Event 15 patched with our service talk group. If I put my scanner on just the event talk group I miss anything that dispatch and any units running on the service talk group say, and then when I select just the service talk group I miss anything from units on the Event channel. Even in scan mode it is irritating because the scan delay is waiting for a reply on one or the other.

Just curious if this is normal or if there is a setting that will make the scanner read the patch information. I guess I would think that if the channels were patched together they would work like the radios and being on either channel would also pick up the other.

I know Davis leaves a couple of there channels patched almost always so I was hoping that you guys could shed some light on this for me. I have also noticed similar things with multi selected talk groups.
 

Observer1

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SLCPD patches each night. Pioneer and Liberty join together in the early morning hours, then split again about noon when call volume dictates each needing it's own channel.

Nothing has to change for the users during the patch, you just hear all traffic from both channels on both channels, when they're split, you only hear Liberty on Liberty and Pioneer on Pioneer.
 

gadgetmikey

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Frequently at night, the police and fire
dispatch talkgroups are tied together (patched). What comes out on the fire talkgroup
also comes out on the police talkgroup. Have had two radios going at the same time on
the different talkgroups and you can hear the slight delay, but the same conversations.
This is what I was doing exactly was I had one talkgroup on one scanner and the other talkgroup on the other scanner an for some reason they were like seperate channels even though the users were obviously talking to each other. I don't understand why there would be a slight delay because in trunking for a patch I think it just sends both radios to the same voice channel. Thats why I thought the scanner was not reading the patch data. In unitrunker you can actually see when the channels are patched together. I have heard the slight delay on different sites or when patched with VHF or UHF channels.

I will play around with it a little bit more.
 

qlajlu

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I was curious if anyone knows how the scanners are supposed to handle patches.

I was using a bearcat BCT15; this weekend for the car show they had Event 15 patched with our service talk group. If I put my scanner on just the event talk group I miss anything that dispatch and any units running on the service talk group say, and then when I select just the service talk group I miss anything from units on the Event channel. Even in scan mode it is irritating because the scan delay is waiting for a reply on one or the other.

Just curious if this is normal or if there is a setting that will make the scanner read the patch information. I guess I would think that if the channels were patched together they would work like the radios and being on either channel would also pick up the other.

I know Davis leaves a couple of there channels patched almost always so I was hoping that you guys could shed some light on this for me. I have also noticed similar things with multi selected talk groups.
gadgetmikey, this same question came up over in the GRE Forum recently. I thought you might be interested in reading what they had to say. It might answer some of your questions.
 

bchris

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Still Learning

Gadgetmikey,

Sorry to keep beating this dead horse, but I think I need some clarification.

It seems like any patch that includes a conventional (non-trunking) channel would have to be done at the system level and not at the radio level, because some or all of the radios would be tuned to only one fixed frequency. Does that sound right? (and w/ conventional only, would we traditionally just call that a repeater?)

With that in mind I guess it never occured to me that in a trunking system each radio could theoretically 'attach' to more than one TG, although that still doesnt seem to me like a logical implementation. Maybe there is something I am not thinking of.

Based on your recent observations and research, do you think that a TG patch is handled by each radio individually, or by the system? If done by the system, then all traffic should be duplicated on all patched TG's, right? If that is true, then why would each radio (including scanners) know or care that the same traffic is occurring on another TG at the same time?

What do you think?
 

gadgetmikey

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On a trunked system when they do a patch or multiselect a channel it sends out a constant data packet on the control channel that shows the patch and what TG's are attached to it. If you go to the link that glajlu attached above they explain it better than I do. I think that I probably made it confusing because our conventional channels are allready patched with 800 mhz TG. A conventional patch would tie up both channels.

Lets say that at night the police dispatcher wants to also cover the fire dispatcher. The police dispatch goes in on her console and patches the fire TG over to the police TG. Now the control channel broadcasts this patch over the control channel so any radios on the fire TG know that they also need to switch over anytime there is any traffic for the police TG. The reason it works like this is because there is no reason to tie up two channels on a trunk system when all they really need to do it tell all the radios to move to the same freq.

The end users radio's monitors this information and acts correctly but the scanners for one reason or another don't. So with the above example if you were holding on the fire TG you would hear the fire units but not the police or the dispatcher.

Hopefully I didn't make that more confusing, sometimes I explain things poorly.
 

bchris

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The reason it works like this is because there is no reason to tie up two channels on a trunk system when all they really need to do it tell all the radios to move to the same freq.
Ahah! There was a good reason that I wasn't thinking of! And you explained it very nicely, thanks.

I am now imagining the possibility of more than 2 or 3 TG's patched together, and every time someone keys a mic it would have tied up all the audio freqs on the smaller sites w/ the same signal. I think I am getting it now.
 

ranger2004

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This link will help you understand how ID's change when certain things happen.
On uniden scanners turn status bits off and you will not miss the calls.
If you want to see when things are patched, etc. set status bits to yes.

I wish i would have found this about 5 years ago.
--------------------------------------------------------------------------------

http://wiki.radioreference.com/index...torola_Type_II

Dec ID + # Usage
ID+0 Normal Talkgroup
ID+1 All Talkgroup
ID+2 Emergency
ID+3 Talkgroup patch to another
ID+4 Emergency Patch
ID+5 Emergency multi-group
ID+6 Not assigned
ID+7 Multi-select (initiated by dispatcher)
ID+8 DES Encryption talkgroup
ID+9 DES All Talkgroup
ID+10 DES Emergency
ID+11 DES Talkgroup patch
ID+12 DES Emergency Patch
ID+13 DES Emergency multi-group
ID+14 Not assigned
ID+15 Multi-select DES TG
 

bchris

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Thanks Ranger2004!

I was just looking for this status bit info last night, because I wanted to use it in a reply to another post.

As it turns out, my attention span is about as big as a flea, and while searching if some 'interesting' post catches my attention, most likely I wont finish my original objective. Thanks for getting me back on track.
 

qlajlu

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What does "DES" stand for?
Dec ID + # Usage
ID+0 Normal Talkgroup
ID+1 All Talkgroup
ID+2 Emergency
ID+3 Talkgroup patch to another
ID+4 Emergency Patch
ID+5 Emergency multi-group
ID+6 Not assigned
ID+7 Multi-select (initiated by dispatcher)
ID+8 DES Encryption talkgroup
ID+9 DES All Talkgroup
ID+10 DES Emergency
ID+11 DES Talkgroup patch
ID+12 DES Emergency Patch
ID+13 DES Emergency multi-group
ID+14 Not assigned
ID+15 Multi-select DES TG
Specifically, what is the difference between a status bit of +1 and +9, or +2 and +10, etc.? ...what is DES?
 
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