Radio ID (Data Bursts) SDS100-200

[n1chu]

On my local PD system, an 800 MHz conventional system with CTCSS PL, I notice some units with and some units without ID data bursts. (The data bursts I do hear precede the transmission.) I’m wondering if I’ve got something programmed that mutes these data bursts on certain units and not on others. (Maybe the mobile units as opposed to the portable units?) I am not finding this option in the menu of the radio but I haven’t checked if Sentinel allows for it. …probably an oversight on my part and I apologize for not seeing it if it’s there…
Do the SDS’s allow for muting of data bursts? If not, why am I not hearing them on some units?

 

[doctordialtone]

I notice some units with and some units without ID data bursts. (The data bursts I do hear precede the transmission.)

You're hearing MDC, used to identify the unit transmitting.

There's no way to mute it.

 

[n1chu]

You're hearing MDC, used to identify the unit transmitting.

There's no way to mute it.

Ok. Accepted. But what accounts for my hearing it on some transmissions but not others?

 

[900mhz]

Perhaps not all of their radios are programmed with MDC.

 

[n1chu]

Perhaps not all of their radios are programmed with MDC.

Perhaps. But I’m going under the assumption they are… thanks for your help.

 

[N9JIG]

It could also be muting via the system itself. Some systems were designed to mute the first half second of a transmission from a mobile unit to prevent the ANI noise from being heard by the users, this was very common in older GE systems that used GE-Star and was often retained when they switched to MDC down the road. Some radios might be set up with a built-in ANI delay or set to POST instead of PRE.

There is also a programming option on Motorola repeaters to mute the ANI, I don't recall if it was a straight timer or if it actually decoded/muted the MDC.

On our system we eventually removed the delay (and turned off the ANI-Mute on the new repeaters) for several reasons. First it often cut out words from the transmitting users as they were prone to quick-keys. Second we transitioned to radios with ANI displays, with the timer these would not display the other calling party's ID. The users complained for about a week of the data bursts but eventually got used to it and eventually learned that if they heard the data it was a mobile unit and not the dispatcher.

 

[n1chu]

It could also be muting via the system itself. Some systems were designed to mute the first half second of a transmission from a mobile unit to prevent the ANI noise from being heard by the users, this was very common in older GE systems that used GE-Star and was often retained when they switched to MDC down the road. Some radios might be set up with a built-in ANI delay or set to POST instead of PRE.

There is also a programming option on Motorola repeaters to mute the ANI, I don't recall if it was a straight timer or if it actually decoded/muted the MDC.

On our system we eventually removed the delay (and turned off the ANI-Mute on the new repeaters) for several reasons. First it often cut out words from the transmitting users as they were prone to quick-keys. Second we transitioned to radios with ANI displays, with the timer these would not display the other calling party's ID. The users complained for about a week of the data bursts but eventually got used to it and eventually learned that if they heard the data it was a mobile unit and not the dispatcher.

I hadn’t considered the agency might be responsible, either knowingly or unknowingly (it’s a small town and there wasn’t any oversight years ago when they moved off the VHF low band. They just called Motorola and asked them to correct problems on an as needed basis. That caused repairs and upgrades to be made without any continuity, so they ended up with some of this, some of that. But it was always with Motorola). What you have suggested makes sense given the agency’s history. Thanks for the help.