Motorola patches

[scanfan03]

Are there any scanners out there that will "track" a TG that is patched to another one? I know that if you do it with a real radio, it has to be affiliating. T4Win can "see" if two TG's are patched, can't a scanner too? Wouldn't it be easy to implement this feature?

 

[JoeyC]

They all will. Patching shows on 3600 baud systems as TG +3 and TG +4. Theres also encryption patches as well, but the status bit escapes me. I'm not sure how patches are represented on a 9600 baud system.

 

[Voyager]

They all will. Patching shows on 3600 baud systems as TG +3 and TG +4. Theres also encryption patches as well, but the status bit escapes me. I'm not sure how patches are represented on a 9600 baud system.

Encryption is usually TG+8, so it would be 11 and 12.

Joe M.

 

[jplyler]

I just looked into this myself. If you use T4Win it will show you which groups are patched. I still don't fully understand it.

Jon

 

[WayneH]

There are no scanners which currently allow decoding and tracking of Motorola patches (tracking by the supergroup [TG+3] with patch members attached).

The trouble with doing this with a scanner is the scanner needs to sit on the control channel long enough to see the patch member announcements. Some systems flood the control channel with them, some it takes several seconds before they reoccur. Then the scanner has to create and store a table of the patch aliases, which is another problem. But, it can be done, the problem is tracking the patches reliably.

-Wayne

 

[Jay911]

Wayne (and/or anyone else in the know),

This topic reminded me of a situation I had wondered about before, but not gotten a chance to see in action (though it happens here often enough).

This relates to patching non-trunk resources to trunk resources and how the result appears in the control channel (i.e. in T4Win/trunker/etc).

In my particular case, a VHF simplex channel will often be patched to an 800mhz Smartzone analog talkgroup, to allow the air ambulance (on VHF) to speak with the fire/EMS crews (on trunk).

When the air ambulance (and/or, I suppose, any activity on the VHF frequency) initiates a conversation, and thus utilizes the 'patch', what radio ID would show up on the patched trunk talkgroup? The RID of the patching Centracom console? Something else? Nothing?

And does the 'patch' (+3) status bit get turned on, or is a conventional/trunk patch not considered the same as a trunk/trunk patch?

No real reason for needing to know - just wondering what would show up in this case.

 

[wsmoore]

On the Motorola 3.0 Smartzone simulcast system in Jacksonville,Fl. Trunker shows the radio id assaigned as the patch radio for anybody using the vhf or uhf channel.If somebody on the system is talking then their radio id pops up on the patch channel.

 

[SCPD]

does the 'patch' (+3) status bit get turned on, or is a conventional/trunk patch not considered the same as a trunk/trunk patch?

When the code in the radio's firmware sees the "+3" or "+7" talkgroup, it knows to check the "look-aside" list of patched talkgroups culled from previously seen patch announcements over the control channel.

If the "patched" call isn't actually linked to another talkgroup, there is no reason to mark it as such over the air.

-rick

 

[scanfan03]

Okay, so I have a BC 246 with Status Bits turned off. If I turn my Status Bits on, and say I want to make sure when 5520 is patched to another TG, I enter 5523? And I will always get the patch from 5520 to what ever TG?

 

[WayneH]

Patching trunked to conventional

There are a few different ways to patch a conventional channel to a talkgroup. I'll stick with the standard way. The standard way the radio id used is the console radio id. The talkgroup has the +3 attached to it.

Centracom console radio ids can be set up in so many different ways it's hard to say what exactly will show up as the radio id (eg., the console's specific radio id when transmitting on the patched talkgroup, or another radio id).

Over the control channel you won't see anything different. There will be a single patch announcement with the supergroup (TG+3) the same as the patch member. Nothing else.

-Wayne

 

[WayneH]

Okay, so I have a BC 246 with Status Bits turned off. If I turn my Status Bits on, and say I want to make sure when 5520 is patched to another TG, I enter 5523? And I will always get the patch from 5520 to what ever TG?

Always? Possibly but that depends on whether the patch is always initiated on 5520. If another member in the patch has the patch initiated on it, 5520 and 5523 will go silent. The traffic will be out over the other TG +3.

This happens most of the time with temporary patches done manually or different consoles initiating the patch and having the patch list set up differently.

-Wayne

 

[scanfan03]

So how do the radios know which "supergroup" to go to. Couldn't scanners use the same method radios do?

 

[Jay911]

So how do the radios know which "supergroup" to go to. Couldn't scanners use the same method radios do?

I think they probably could, but it would involve having the scanner 'listen' to the control channel a lot longer than it does now, in order to pick up the proper patch ID. I think Wayne mentioned earlier in this thread that it's not always transmitted constantly.

Another thing I was thinking of, which may or may not be true (and most likely isn't), is that the scanner can't use the exact same code as the radios, or else software copyright laws come into play. Perhaps doing a couple of things 'a little differently' ensures that there's never a chance of being accused of code infringement...

 

[WayneH]

I think they probably could, but it would involve having the scanner 'listen' to the control channel a lot longer than it does now, in order to pick up the proper patch ID. I think Wayne mentioned earlier in this thread that it's not always transmitted constantly.

Right. There are specific "OSWs" which say which TGs are members of a patch. There is one announcement per patched TG. Each announcement has the supergroup (TG+3) and the talkgroup involved (which will now be quiet). On a busy system or a SmartZone system, which has a lot more background data, it takes a good amount of time (longer than a few seconds for sure) to compile a table of what's patched to what.

-Wayne

 

[scanfan03]

Thanks for all of the help on this topic!

How do radios compile the tables really fast?

 

[WayneH]

Thanks for all of the help on this topic!

How do radios compile the tables really fast?

In reality not many subscribers (ie., NOT joe schmoe with his ASTRO Saber programmed for every conceivable system in the area and only listens) scan across systems. The radio is predominantly listening to the control channel and spends way more time than a scanner does listening to it.

-Wayne

 

[scanfan03]

So, does that mean they could make a scanner that like you could specify for one or two channels to look for patches and when it found a characteristic, stay on the control channel for a longer period of time to look for the table?

Thanks for bearing with me, I know a lot about trunking, just not the advanced parts of it.

 

[WayneH]

I can't say. A lot of things are possible but I'm not familiar with designing scanners. With the Uniden you can define a hold time to sit on the control channel but I like scanning each system as quick as possible and moving on.

-Wayne