London City System

[wolfie161616]

Some information first then a question, this is on the London city system, I keep getting a hit like this on my Uniden BCD436, this appears to be two channels patched together from what I can tell (Maybe auto-generated TGs?), I never get audio when I get a hit on this, and there are 3 different that appeared in a row 50 seconds apart
(See images At Bottom)

my question is, am I right to think this is a patch? Dose anyone have information one what these TGs are if that is the case? what does the i at the start of the TG mean? And lastly what is (SRC) and (DST)?

Thank you for any information anyone has, and any help anyone can provide!

Much appreciated
Jade

 

[gary123]

Those look like private calls.

 

[mciupa]

The "i" is a radio identifier, although the scanner is calling it a talkgroup "SRC" is the source radio in the conversation and "DST" is the destination radio the the source is wanting to communicate with. And like the post up above, they want to keep their conversation private.

It would be interesting to see which group has radios in that range: PS,FD, PW etc...

 

[wolfie161616]

Those look like private calls.

I never even though about that, Thanks for your help!

The "i" is a radio identifier, although the scanner is calling it a talkgroup "SRC" is the source radio in the conversation and "DST" is the destination radio the the source is wanting to communicate with. And like the post up above, they want to keep their conversation private.

It would be interesting to see which group has radios in that range: PS,FD, PW etc...

Very Interesting! And looking at it now, the RID 14538 is LFD Dispatch and 14603 fits how LFD does their RID's but i have never logged that one before.
Anyways thank you very much for the help and for explaining that to me.

 

[Muxlow]

Using data decoding software like Unitrunker, when the dispatcher goes to page a station, they more or less are doing i-Calls to each one to set off each specific Station Alert System. You'll see a bunch of radio id's come up all at once then you'll hear voice over on the Alerting talkgroup

 

[wolfie161616]

Using data decoding software like Unitrunker, when the dispatcher goes to page a station, they more or less are doing i-Calls to each one to set off each specific Station Alert System. You'll see a bunch of radio id's come up all at once then you'll hear voice over on the Alerting talkgroup

Interesting, I'll keep that in mind going forward.

Thanks!

 

[wolfie161616]

In case there was any doubt about what was causing this, I put my radio into Discovery Mode and you all are correct!

What happens is when LFD sends out a page, before we hear tones or Dispatch voice it creates a Private Call between Dispatch and the stations that are being Alerted (IE. A call came for station 1, 4, 6. before tones my radio got a private call from LFD Dispatch RID to 14601, another one for 14604 and another for 14606 and once all 3 had come through then my radio switched to station alerting)

What's interesting to me is 146## is not what I have logged for the base stations for LFD. Whenever they use them, their RIDs for the stations come as 14501-14514 (Station 1-14)

So I wonder if this is a backup way for them to page stations if the Station alerting channel were to ever become unavailable, or perhaps a way for LFD to send a page if they didn't want it in the open air or all to hear? I only wonder that because to my knowledge LFD Doesn't have any encrypted channels.

Thoughts?

Jade

 

[Muxlow]

Its similar to how EMS gets pages. The base station itself is its own radio with its own radio ID that they can talk on. The station altering radio would be tucked away someplace its its just there to set off the station tones. So has a different radio ID # and wouldnt have a microphone on it. Its always sitting on a specific talkgroup.
Its only purpose is to receive the i-call and trigger the station alert system

 

[Forts]

^^^ exactly this. Set off station tones, turn on lights and possibly open bay doors.

 

[Forts]

Just FYI I removed a couple of talkgroup submissions that were recently added to the London system as they were not accurate... I believe they were group 408 (water tender) and 409 (patch to common). LFD does not have a water tanker/tender talkgroup, nor do they patch to a 'common' channel. The only patching they occasionally do is to the county fire channels, and that is done using TAC 5.

There are several talkgroups (406 thru 410) that are sometimes used for testing, but nothing operational or fire ground related.