Radio Affiliations

[rescue161]

A radio does not have to affiliate to a system to be inhibited. It's true that if the radio is properly programmed for NAS that it will never affiliate, but if a system admin sends an inhibit command to all IDs that fall outside the range of legit radios, those NAS radios will be inhibited, regardless of whether they send back an acknowledgement.

Duplicate IDs most certainly will wreak havoc, especially on a legit subscriber that thinks he's on a certain talk group. I should post my findings of some tests that we did on our system.

 

[W4ZMJ]

The default id is 1 any way I just leave as is and use one conventional frequency per zone and scan off that to monitor that's the way I seen it done on a video on you tube and have had no issue

 

[Giddyuptd]

I have seen consoles using the ID of 1 before. So imagine that havoc.

 

[Ant9270]

A radio does not have to affiliate to a system to be inhibited. It's true that if the radio is properly programmed for NAS that it will never affiliate, but if a system admin sends an inhibit command to all IDs that fall outside the range of legit radios, those NAS radios will be inhibited, regardless of whether they send back an acknowledgement.

Duplicate IDs most certainly will wreak havoc, especially on a legit subscriber that thinks he's on a certain talk group. I should post my findings of some tests that we did on our system.

Before I write my response, I want to disclaim I am NOT trying to stir the pot, but trying to learn. I am just curious, how can a radio respond to said stun command if the CC TX Frequencies are wrong? I guess the response doesn’t really matter because it can RECEIVE said inhibit.

 

[K2NEC]

In theory if the TX frequency is wrong it should never affiliate right?

Before I write my response, I want to disclaim I am NOT trying to stir the pot, but trying to learn. I am just curious, how can a radio respond to said stun command if the CC TX Frequencies are wrong? I guess the response doesn’t really matter, because it can RECEIVE said inhibit.

 

[APX8000]

A radio can in fact affiliate even if it’s on a conventional channel scanning a trunked talkgroup list that is hidden in 17 and above. Example...Site A and Site B share the same core. You are scanning Site A because XYZ PD uses Site A. You set coverage type to “Disabled” but forget to set the correct RFSS and Site number. Even though you have nothing from Site B programmed in your radio (not even one control channel), if you roam into Site B’s coverage area and a sampling of the RSSI is stronger, it will try to affiliate on to Site B.


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[rescue161]

A radio does not have to respond to a stun command. It may try to respond, but if it can't due to programming or removed PA, it will still accept the stun command. On a Harris system, if the radio did not respond to the inhibit command, the UAS will just report "Disabling Unit" for the RID that was sent the inhibit command. If the UAS got a response from the RID, then the UAS would report "Disabled Unit." In either case, if the RID received the inhibit command, the radio would still be stunned.

Also, the radio does not have to be affiliated to be stunned. Say you pick an ID out of the blue, we'll use 2910001. And say that is a legit ID. Say you did everything right and were not seen by the sysadmin and everything is great. Then the real user loses their radio and the sysadmin sends an inhibit command to 2910001. It will zap the real radio and your radio. Even though you were not causing a problem, your radio still got killed. It is a crap shoot and you have to accept the consequences when programming NAS. Either by using a legit ID or a random, out of range ID. Some system admins have more time than others to do things like stun any RID outside of their legit ranges.

 

[zz0468]

In theory if the TX frequency is wrong it should never affiliate right?

Unless properly programmed for NAS, entering a wrong TX frequency will result in the radio displaying "NO COMMS" when it tries and fails to affiliate.

 

[APX8000]

Or how about this about duplicate IDs....

I turn on my legit radio ID 1234567. Radio is set to channel 1 which is TG 123. The controller says, “hey, 1234567 is on TG 123 (Police Main) so pass allow channel grants on it.

You turn on your radio in which you cloned my ID. Your radio is on your channel 1, which is TG 456 (Car to Car not monitored my dispatch). Controller says “Oh, radio ID 1234567 switched channels, he is over here now.”

I can’t remember if it bonks first or keys the wrong talkgroup or screws with the RX talkgroup. We’ve tested it.. Will have to check our notes.


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[Ant9270]

Unless properly programmed for NAS, entering a wrong TX frequency will result in the radio displaying "NO COMMS" when it tries and fails to affiliate.

It depends on the system. With an older system (Smartzone OBT) for instance, it’ll never show no comms even if the TX frequencies are way off. However, I believe on a legacy 8+ system it will show and KNOW something is off.

 

[KevinC]

Or how about this about duplicate IDs....

I turn on my legit radio ID 1234567. Radio is set to channel 1 which is TG 123. The controller says, “hey, 1234567 is on TG 123 (Police Main) so pass allow channel grants on it.

You turn on your radio in which you cloned my ID. Your radio is on your channel 1, which is TG 456 (Car to Car not monitored my dispatch). Controller says “Oh, radio ID 1234567 switched channels, he is over here now.”

I key up my legit radio...guess which talkgroup I key up on even though my radio is on Channel 1 Police Main. Hopefully I’m not getting shot at.


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What "should" happen in that case is you get a bonk, then a channel grant on the correct TG (on a MSI system using MSI subscribers, can't speak for other brands).

 

[APX8000]

Ok. We were just discussing this offline. We believe that whenever you key up, the radio always sends an inbound packet announcing both the SID and the TGID you're trying to TX on.

We were also discussing what happens if a duplicate ID registers on a whole different site, even if it's the same talkgroup. The theory is that if your radio was the only one affiliated with a particular TG on Site 1, and someone with your cloned ID affiliates with the same TG on Site 2...you’re not going to hear anything because the system will no longer have that TG active at that site.

 

[KevinC]

We were also discussing what happens if a duplicate ID registers on a whole different site, even if it's the same talkgroup. The theory is that if your radio was the only one affiliated with a particular TG on Site 1, and someone with your cloned ID affiliates with the same TG on Site 2...you’re not going to hear anything because the system will no longer have that TG active at that site.

Correct and that could be hazardous to your health.

 

[GTR8000]

A radio can in fact affiliate even if it’s on a conventional channel scanning a trunked talkgroup list that is hidden in 17 and above. Example...Site A and Site B share the same core. You are scanning Site A because XYZ PD uses Site A. You set coverage type to “Disabled” but forget to set the correct RFSS and Site number. Even though you have nothing from Site B programmed in your radio (not even one control channel), if you roam into Site B’s coverage area and a sampling of the RSSI is stronger, it will try to affiliate on to Site B.


Sent from my iPhone using Tapatalk

Or how about this about duplicate IDs....

I turn on my legit radio ID 1234567. Radio is set to channel 1 which is TG 123. The controller says, “hey, 1234567 is on TG 123 (Police Main) so pass allow channel grants on it.

You turn on your radio in which you cloned my ID. Your radio is on your channel 1, which is TG 456 (Car to Car not monitored my dispatch). Controller says “Oh, radio ID 1234567 switched channels, he is over here now.”

I can’t remember if it bonks first or keys the wrong talkgroup or screws with the RX talkgroup. We’ve tested it.. Will have to check our notes.


Sent from my iPhone using Tapatalk

What "should" happen in that case is you get a bonk, then a channel grant on the correct TG (on a MSI system using MSI subscribers, can't speak for other brands).

Ok. We were just discussing this offline. We believe that whenever you key up, the radio always sends an inbound packet announcing both the SID and the TGID you're trying to TX on.

We were also discussing what happens if a duplicate ID registers on a whole different site, even if it's the same talkgroup. The theory is that if your radio was the only one affiliated with a particular TG on Site 1, and someone with your cloned ID affiliates with the same TG on Site 2...you’re not going to hear anything because the system will no longer have that TG active at that site.

Correct and that could be hazardous to your health.

Gee, all of this stuff sounds awful familiar!

 

[zz0468]

It depends on the system. With an older system (Smartzone OBT) for instance, it’ll never show no comms even if the TX frequencies are way off. However, I believe on a legacy 8+ system it will show and KNOW something is off.

Ok. I do know that, with both Type 2 Smartnet and 7.x, if it sees a control channel and attempts to affiliate but gets no ack to that attempt, the radio will indicate no comms.

 

[rescue161]

On our Harris system, we took several radios and programmed two of them with the same ID. So, we had radio IDs 1234 & 5678 on a test TG 987, both radios affiliated and were talking back and forth on 987. We had another radio that we programmed with 1234 and turned it on another talk group, 063. So now that 1234 is affiliated with 063, when either of the legit radios keys up, the transmission goes across both 987 & 063. By having two radios with the same ID, it essentially created a patch as well as a lot of confusion on the unsuspecting legit users. The behavior that we experienced was not what Harris told us would happen. They told us that if two radios had the same ID, that the first would affiliate and the second would be denied affiliation. This was not what happened.

 

[GTR8000]

On our Harris system, we took several radios and programmed two of them with the same ID. So, we had radio IDs 1234 & 5678 on a test TG 987, both radios affiliated and were talking back and forth on 987. We had another radio that we programmed with 1234 and turned it on another talk group, 063. So now that 1234 is affiliated with 063, when either of the legit radios keys up, the transmission goes across both 987 & 063. By having two radios with the same ID, it essentially created a patch as well as a lot of confusion on the unsuspecting legit users.

Well, that's certainly interesting behavior. An ASTRO 25 system will simply process the affiliation by the cloned (second) radio as if it were the original radio changing talkgroups, which certainly seems like the expected behavior in that situation.

The behavior that we experienced was not what Harris told us would happen. They told us that if two radios had the same ID, that the first would affiliate and the second would be denied affiliation. This was not what happened.

Frankly, I don't quite see why the second would be denied affiliation, since as far as the system should be concerned there is only a single ID requesting affiliation to a talkgroup. The system should have no knowledge of an ID being cloned across two or more radios.

Unless some sort of authentication is being used, whereby the system is aware of an ESN or other such method of authenticating a subscriber beyond simply the subscriber ID. Interesting, nonetheless.

 

[rescue161]

I think they may have been talking about LLA, but you never know.