Mic clicks, but no voice

captclint · #1 (**permalink**) 12-12-2008, 10:42 AM

Several TGID's on the LTR's in my area only transmit Mic clicks. Sounds a little like Nextel clicks, but I don't think they are. I think Nextel are a little more "musical" in sound...these are just rapid series of clicks. I hear the same type of noise when our FD's transmit on conventional(only FD's never just transmit clicks on purpose). Then, I found one system that also transmits voice, as well as just Mic Clicks, and the clicks are heard, like the FD's, for each voice transmit.

Can anyone tell me what is going on with these annoying sounds being the only traffic, which appear to be unique to a trunked sys?

N2DLX · #2 (**permalink**) 12-12-2008, 12:41 PM

It may be Kenwood's FleetSync signaling format. I often hear them on their own talkgroups just beaconing data away with no voice traffic. Finding an audio clip online is a chore, so maybe I'll make a quick recording and post it.

N2DLX · #3 (**permalink**) 12-12-2008, 01:07 PM

Here's the samples.. one is a Pre ID, the other is data sent on data-only talkgroups.

Is this what you're hearing?

captclint · #4 (**permalink**) 12-12-2008, 01:15 PM

Quote:

Originally Posted by N2DLX

Here's the samples.. one is a Pre ID, the other is data sent on data-only talkgroups.Is this what you're hearing?

Exactly!! Thanks. So the data-only is the Mic click only, but what is the purpose of the PRE on voice?

N2DLX · #5 (**permalink**) 12-12-2008, 01:51 PM

Quote:

Originally Posted by capt_clint

Exactly!! Thanks. So the data-only is the Mic click only, but what is the purpose of the PRE on voice?

It's a signaling format similar to MDC1200, only made by Kenwood. So when you hear the short burst before or after voice, it's sending out an ANI ID, like what you hear with MDC1200. This way a dispatcher or other radio users can see who keyed up.

The data-only transmissions are probably used for sending short messages to field radios, say, to give drivers addresses or jobs to take, etc. It could also be used to send GPS updates to the dispatcher.

They likely assign data-only talkgroups for this purpose so people on voice channels don't have to hear all these bursts of data. Voice comms are on one talkgroup, data is on another.

RADIOGUY2002 · #6 (**permalink**) 12-16-2008, 04:50 PM

Just got to know where to look.......

http://cimtechcorp.com/

http://www.kb9ukd.com/digital/

Food for thought.......................................Back to the basics.

N2DLX · #7 (**permalink**) 12-16-2008, 05:12 PM

It isn't on the kb9ukd site and Google didn't lead me to the other. Trust me, kb9ukd is top of my list..

RADIOGUY2002 · #8 (**permalink**) 12-17-2008, 03:35 PM

Ah, cool we have a mutual site. LOL No, I know it was not their and I had submitted a file way back when with a audio bit from oakbrook fd here in IL. They utilize both version's of signalling format, mdc1200 and fleetsync. As does my fd, the only difference is the admin use the fleetsync as opposed to the regular staff. It's a nice way to know who is who on the air by the chrip. But, thats changing as more fd's start replacing out their stuff from motorola to kenwood, relm etc here.