LASD beeping around 0320 hours?

[Radiocar]

If any of you fine LASD aficionados or SCC Superstars can help a brother out it would be most appr3ciated.

Okay, so I'm kinda nocturnal by nature so I generally catch a lot of code 9 10-29Vs* and 459s on the dispatch channels really late at night. I don't know if I have been hearing this for years and never noticed it or its a new thing the Communications guys are doing, but usually around 3:00 am or so I hear these strange tones on the special dispatch channels (SUD, SEB, SAR) and I know for fact it's not a busy tone or the repeater IDing. I summed it up to nightly testing but I don't really know for sure. It starts about 3:20 and ends a little before 4:00 am. It's a little sporadic in its timing and the beeps are far more drawn out. I doubt it a unit keying because I never hear SCC or a station dispatcher respond or prompt a call out. Could it be a data transmission? I could've sworn that they did this on the 5 and 8 meg MDT channels... I'm pretty stumped, to be honest.

The tones sorta goes like

[------ --------- -------- -------]

These are longer intervals then the busy tone which is something along the lines of;


[--- --- --- --- --- --- --- --- ---]

I couldn't find any information on this and the few midnight deputies that I've talked to swears that it's a simple busy tone.

I would be more than happy to stay up tonight to provide a sample if it helps further my investigations. 😪❌...


Grateful for any input. Thanks!

 

[PaulNDaOC]

These a referred to a test tones. A techie person could explain ti in detail, but what I can tell you is at 0300
daily begins an automated test of all the transmit sites by sending out tones.

The test starts with Dispatch 1, then 2, and so on,,skipping a busy freq, and coming back to it later.

The first sequence is heard as a series of 3 beeps. Each series of 3 indicates on site tested on that frequency.

The test for Dispatch 2 for example goes quickly, as there are/were just two transmit sites (Baldwin Hills/Verdigo), and many more on a channel like SCC access or Disp 7 that covers a lot of area and has many more sites, and seems like it goes on forever.

If you count each series of three, this will tell you how many transmit sites are active on the frequency.

The system also does another test afterward where a high pitched tone is sent out separately from each site, in a quick manner. (You will notice the signal strength vary as that tone changes sites rapidly).

A mic keying up will stop the test, but it will be repeated again at the end, til complete.

If the air is dead, the test goes quickly. If busy then it takes longer, start to finish.

The techs from time-to-time manually do the second test, when a complaint is received about a possible site issue.

 

[Radiocar]

I knew I could count on the wealth of knowledge that is Rad-Ref. Thank you for educating me.

 

[mancow]

I was in LA and heard that. I couldn't figure out what the hell they were doing. Thanks for the info.

 

[mikegilbert]

Thanks for the answer! I was curious about those tones as well.

 

[jrholm]

Or just because someone wants to make sure the early morning units are staying awake

 

[Radiocar]

Might be true dude... There were times when the dispatch channel has gone quiet for over a hour or so and I would fall asleep at my desk or would be in bed and would slowly jar awake to the rythmic beeping on frequency.

 

[PaulNDaOC]

Or just because someone wants to make sure the early morning units are staying awake

That long burst wakes the dead resting peacefully right underneath the Rio Hondo site.