System 2088 NXDN

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mmisk

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Saturday morning update:

.... now I am not so sure......

Today it shows Ran-1, ENC TG 101, and RID= 1001, however is not matched with site 1.
....???

Well, this certainly is a strange turn of events!!
 
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DaveH

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Found that one also. Checking things yesterday AM, still have not determined the 2nd VC for Site 1, which does not seem to be one of those listed (although they are active on some site).

Matching the RAN to site number works, if the unknown channel is in the same system. VHF NXDN is popular in West Quebec and there are other active channels, so I try to match TGs, RIDs, and radio names to the known system (which I did).

Nothing heard on 164.775/164.7625 (I will include 7.5kHz channel when in doubt). 164.925 belongs to another system.

I found 165.735 by putting my 1988 non-trunked analog scanner into search mode.

Dave
 

mmisk

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163.305 is tracking as ch4 on site 1.

On Monday, 163.305 is tracking as ch4 on site 1.

Site 1 is busy today, leaving it on site 2 now but it is quiet.

Sounds like everything is enc.
 
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DaveH

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On Monday, 163.305 is tracking as ch4 on site 1.

Site 1 is busy today, leaving it on site 2 now but it is quiet.

Sounds like everything is enc.

Unfortunately ENC, at least hoping fire would stay clear. You can get an idea what might be going on by TGs and radio names, and general level of activity, that's about it.

Apparently they've been shuffling frequencies among sites...

BTW listening to the old MRC police channels 153.530/153.635/153.785/165.750, not longer hearing anything. Also they had a couple of links around 414MHz. Anyone know about VRs, they used UHF analog, probably changed.

Dave
 

mmisk

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154.445 looks like Site 3 VC 12

Have a listen here: 154.445 looks like Site 3 VC 12

Also: 164.490 looks like Site 3 vc 11 ?
 
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DaveH

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I think 164.490 is Site 3 of a different system. Often (as yesterday) I hear CC on 164.355 which is CKH661 in the IC database. Related channels are 164.490, 166.050 and 166.290. That system was not busy on sunday so did not hear action on any of those.

Dave

Actually, it could be the MRC system if Site 3 is geographically far enough from the other system which is at Rigaud. That's the problem with being able to hear two systems with possibly overlapping frequencies. TG/RID matching should help.
 
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mmisk

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Have a listen to: 164.985

Have a listen to: 164.985.

There is a definite correlation to TG's and RID's on this system L-2088.

Something else that is confusing, the voice channels may be "simulcast" (for want of a better technical description) between sites.

If you can monitor two or more site control frequencies, you will see what I mean.
 

DaveH

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I'll give 164.985 a listen, but didn't hear it after several scans through that part of band. Was off yesterday, spent some time trying to untangle (?) this system, with some limited luck.

None of the Site 1 VC's are as listed on DB . Channel 2 is still unknown at the end of the day. Channel 4 is 152.4275 which is sandwiched between Site 2 CC 152.4200, and another NXDN48 CC on 152.435 for MRC de Papineau system. They are increasingly packing channels on 7.5kHz spacing. Using older receiver with wide selectivity, can be confusing. By use of different antennas plus attenuator I was able to narrow this down.

Site 4 (CC 151.9100) has four channels 13-16, frequencies unknown.

Site 2 channel 6 is 152.9900 which is 7.5kHz below another CC for MRC de Papineau on 152.9975.

Problem finding the above was they were "hiding in plain sight" close to other CC's.

Did not hear anything on 163.305 or 167.675.

A small bit of clear voice came through, expect it was an anomaly.

Dave
 

slicerwizard

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Something else that is confusing, the voice channels may be "simulcast" (for want of a better technical description) between sites.
Yes, some users of a talkgroup are on one site, while others are on another site, and they can all hear each other. It's the whole point of building a multi-site networked system...
 

mmisk

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Dave H.- "Apparently they've been shuffling frequencies among sites..."

Hi Slicerwizard, I have not observed this before: the VC numbers change........

For example, 165.735- VC 3 on site 1 also shows up as ch 8 or 2.
And 154.445-ch12, Site 3, shows up as both 12 or 8.

This makes things somewhat confusing, but fun to collect the info on various systems.

Summary of voice channels found:
Site 1- 165.735-ch3, 163.305 ch4, 164.985 - ch 2
Site 2- 152.4200cc5 164.925-ch6
Site 3- 154.445-ch12 , 164.490-ch11
 

DaveH

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Definitely something odd going on.

Watched several complete VC rotations on Site 1 on Wednesday, did not see 163.305 active (at all during the day).

154.445 showed up with RAN=2 -> Site 2.

Last night, heard 164.985 but the signal was too weak to be Site 1, unless its TX power is down, and did not have computer monitoring at the time.

And can't explain some of the other differences...like 152.9900 and 152.4275.

I could see possible re-use of same frequency with enough distance, or could be a form of simulcast?

Simultaneous transmission across sites makes sense as system requirement, as old police-only system used to do that.

BTW does anyone (from the Quebec side) know locations, even approximate, for Sites 2, 3 and 4?

Dave
 

mmisk

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screen capture for 163.305.

Here is a screen capture for 163.305.

At the time it was the VC for Site 1, TG 101, and radio 10090.

Notice that DSD (VC from SDR), data displays Ran 3.
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ADDED: I see that image is not very clear, I can email you the original.
 

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DaveH

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Hi Mike,

No problem, can see the numbers well enough.

TG 101 is police, so we expect same TG/RID should appear on all sites at the same time, but different channels/frequencies. 163.305 with RAN=3 should belong to Site 3. Three other VCs will be active in the system also. Your SDR scope is not wide enough to cover 152+ and 162+ bands at the same time. Would be interesting to see what's happening at the lower frequencies (152); try plugging in one of those (152.9900 and 152.4275) in addition to Site 1 CC.

Dave

On second thought, maybe broadcast not all sites all the time; but certainly more than one at least in some circumstances.
 

mmisk

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At the moment Site 1 and Site 2 are both transmitting the same TG and Radio on both systems.

So this is why I can't really be sure of what frequency corresponds to what VC number.

Site 1 CH 2 is transmitting the same TG on Site 2 CH 8
Site 1 CH 3 is transmitting the same TG on Site 2 CH 6
Site 1 CH 4 is transmitting the same TG on Site 2 CH 7

Too bad about encryption, but it is here to stay.

I will see if I can listen to both site 3 and 4 but they are weak her

Yes that is a good point using the ran number to place the frequency with the correct site.

Mike
 

mmisk

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(152.9900 and 152.4275)

Hi Mike,

try plugging in one of those (152.9900 and 152.4275) in addition to Site 1 CC.


OK here is what I found, I would never have found the 152.4275 but it is there and active.

152.990- Ran 2 CH 6

152.4275- Ran 1 CH 4

165.735- Ran 1 CH 3

So if what DSD is showing then they should be correct.

Checking the others now.
 
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mmisk

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So for 163.305 it shows Site 3 and CH 10

So for 163.305 it shows Site 3 and CH 10.

Site 3 is not busy at this time.

We are very lucky to have the amazing software available thanks to those that give their time to produce it.

Years ago when OPF went to provoice (1999 approx.) I began searching for a digital audio decoder and the only one I found was DSD.
Well it did the job of listening to provoice comms. It only ran on linux, then a talented person ported it to windows and this was much easier to implement. I don't think there is any other audio decoder available that will do this.

MM
 
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mmisk

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MRC Saturday Update

Saturday Update:

-Site 1-
1- 164.025- control
2- 164.925- voice
3- 165.735- voice
4- 152.4275- voice

Site 2-
5- 152.420- control
6- 152.990- voice
7- 153.515- voice
8- 154.445- voice

-Site 3-
9- 162.570-control
10- 163.305- voice
11- 164.490- voice
12- 164.985- voice

Site 4-
13- 152.910-control
14- Unknown
15- Unknown
16- Unknown
 

DaveH

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Sorry, 152.9900 on Site 2 I reported is actually 152.9825, 7.5kHz lower. It's adjacent to RENIR P25 CC on 152.97500.

Site 2 CH 7 is 153.51500, found/confirmed yesterday also.

Looks like 158.09(25) and 169.8000 must belong to Site 4 but need to verify.

Dave
 
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