PRO197 and P25 Simulcast Dispatch

[NCFire11]

It was my intention to broadcast the FC P25 audio for the fire and ems side. The problem arises when my County dispatches both fire and ems to the same call.

When they are about to dispatch a call they:

-Patch FC Fire and FC EMS talkgroups together
-Play a short alert tone followed by something like "Youngsville Rescue, EMS, Youngsville Fire standby 10-50 PI"
-Send the tones over the Analog channels
-Dispatch the call
-Unpatch the channels

My PRO197 doesn't seem to be able to comprehend whats going on. Do you know a solution to this? If I set it on the Fire Disp TG (117) I hear absolutely nothing until units begin checking enroute, etc.

 

[troymail]

It was my intention to broadcast the FC P25 audio for the fire and ems side. The problem arises when my County dispatches both fire and ems to the same call.

When they are about to dispatch a call they:

-Patch FC Fire and FC EMS talkgroups together
-Play a short alert tone followed by something like "Youngsville Rescue, EMS, Youngsville Fire standby 10-50 PI"
-Send the tones over the Analog channels
-Dispatch the call
-Unpatch the channels

My PRO197 doesn't seem to be able to comprehend whats going on. Do you know a solution to this? If I set it on the Fire Disp TG (117) I hear absolutely nothing until units begin checking enroute, etc.

Took me a bit to figure out that FC means Franklin County... Anyway, perhaps that dispatch is on a different TGID other than 117? I see from the RR listings that there is no TGID 118 listed but the is a 117 and then 119-125....

My suggestions (from several hundred miles away)....

Program and see if anything appears on TGID 118....

Other than that, you may want to program a wildcard and search for additional TGIDs....

 

[NCFire11]

That was my thought, however on the Harris radios it comes over fine on 117? Ill set it for wildcard either way to see what I see.

 

[troymail]

That was my thought, however on the Harris radios it comes over fine on 117? Ill set it for wildcard either way to see what I see.

Does the (real?) Harris radio display the ID of the talkgroup (117) or just the label of the TG?

 

[NCFire11]

The XG-75, XG-100, and M7300s just show FRE DISP like theynormally would. When they dispatch the radios says ANNOUNCE at the top, which makes me think something else is going on here.

 

[troymail]

Take a look at the Fire TGs for the Baltimore City system -- notice the talkgroups with "Announce" in the name

Baltimore City Trunking System, Baltimore, Maryland - Scanner Frequencies

May just be coincidence....

If the radio is displaying something else like "ANNOUNCE", it makes me think -- different talkgroup ID

 

[NCFire11]

So basically they are using another talk group to dispatch that the P25 radios can comprehend but not the scanner? How come they don't just patch the talkgroups together? Looks like I need to let Pro96com run a little while.

 

[troymail]

I'm only speculation at this point. If you can hear it on a (real) subscriber radio, there are probably several possibilities.

Pro96Com might be a good place to start.... I'd also start searching for new TGIDs (wildcard, etc.)

 

[KevinC]

What's your CPU version?

I believe one of the early updates added patch capability.

Link to the discussion...

http://forums.radioreference.com/ra...7-cpu-1-8-dsp-1-4-released-4.html#post1372887

 

[NCFire11]

I will look at my version when I get home. I think I have it already because I have seen ptch at the top of he screen several times, but not during dispatches.

 

[NCFire11]

after running wildcard a bit I have found out that when both fire and rescue are dispatched a completely different talkgroup is used. This is the same for when the dispatchers make an emergency announcement on law1/law2.


can anyone explain why they would do this instead of using multiselect?

another question..

my feed is up and running, the audio is fine. If i happen to bump my scanner(ie tap it on the top) the noise comes over my feed. I can even talk loudly and hear it over my feed. The scanner is using the linein on my computer and there are no microphones hooked up to my comp. any ideas?

 

[WA0CBW]

In general a multiselect requires a resource (repeater) for each talk group selected. An announcement group gathers all the groups into one resource (repeater) thus conserving resources (repeaters).

 

[NCFire11]

so in short a different talk group is used but the radios are still told to listen to it?

 

[troymail]

after running wildcard a bit I have found out that when both fire and rescue are dispatched a completely different talkgroup is used. This is the same for when the dispatchers make an emergency announcement on law1/law2.

Glad we were able to figure it out!

I run a wildcard about 99.9234% of the time for just these types of things.

 

[troymail]

Don't forget to submit your finds!

Franklin County Project 25 Trunking System, Louisburg, North Carolina - Scanner Frequencies

 

[Halfpint]

My feed is up and running, the audio is fine. If i happen to bump my scanner(ie tap it on the top) the noise comes over my feed. I can even talk loudly and hear it over my feed. The scanner is using the linein on my computer and there are no microphones hooked up to my comp. any ideas?

Sounds like you've got something, either inside the scanner or in the `chain' between the scanner and the computer, that's `microphonic'. While it may be a bit of a long shot the very first thing I would check would be the cable, and it's associated connectors on both ends. I'd use the absolutely shortest cable between the two and I'd also make certain that both connectors had a light coating of CAIG ProGold connector enhancer applied. The next step would be opening up the scanner and take a plain old wooden pencil with a fairly good eraser and start tapping around lightly, with the eraser end (And, yes, I've actually had even `techies', who *should* have *known better*, `forget' and use the sharpened lead end! {GRIMACE!!!}), inside the scanner listening for any sounds it may create. Once you find `the microphonic part', depending upon what it is, I'd find a `non-destructive' way `dampen' it/change it's resonnance'. (Maybe just a small dab of some silicon, a small bit of self-stick foam rubber, or some other non-conductive material?) I'd also make certain that all screws and nuts were properly tightened, but not over torqued as that could *possibly* make things worse. (You *don't* have to go `godzilla'. {VB GRIN!})