BCD996P2: Dispatcher Garbled, Patrols Cars not

mpagano

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Joined
Dec 23, 2019
Messages
7
Strange audio issue. The patrol cars come in very clear but the dispatcher is consistently garbled. Sometimes I can't really tell what they are saying.

Scanner: BCD996P2
Firmware: Latest
Antenna: included antenna with 40 Foot LMR400 cable mounted in the attic

Site: New Jersey Interoperability Communications System (NJICS)

Distance to tower: 2.14 miles, no line of sight

Talkgroup:
4915 1333 Te Oakland PD Oakland Police Law Dispatch

APCO Mode: auto
Threshold: 8
State: off
Hold Time: 0
Modulation: nothing set

I've scanned the forums and it appears either your audio is garbled or not. Not this problem, where only the dispatcher is garbled.
 

sparklehorse

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Portland, Oregon
Yeah, that's a weird one. Is your signal strength the same for both sides of the conversation. If the signal on the dispatch side is weaker that would explain it. It's unusual for a system like that to transmit mobiles on one repeater and dispatch on another, but maybe would occur in some circumstances. Don't know.
.
 

bemyax

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Jun 13, 2011
Messages
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Location
Waterloo, Iowa
I experienced a similar anomaly two weeks ago on my 536. Dispatcher only, bad audio decode. Without going into my odd setup, I was not able to resolve the issue, but it righted itself despite my efforts. I thought it was related to the heavy rain and cloud cover we were experiencing, so I gradually shifted my yagi around. No improvement. The only hair-brained thing I can think of is that there was a degradation of the microwave link from the dispatch location over to the simulcast ring. Since they are all using commercial grade equipment, they were not asking for repeats. But the 536 is not par excellence on digital decode, so it couldn't quite keep up. :rolleyes:
 

mpagano

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Joined
Dec 23, 2019
Messages
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Yeah, that's a weird one. Is your signal strength the same for both sides of the conversation. If the signal on the dispatch side is weaker that would explain it. It's unusual for a system like that to transmit mobiles on one repeater and dispatch on another, but maybe would occur in some circumstances. Don't know.
.
Thanks, I will check that.
 

mpagano

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Joined
Dec 23, 2019
Messages
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I experienced a similar anomaly two weeks ago on my 536. Dispatcher only, bad audio decode. Without going into my odd setup, I was not able to resolve the issue, but it righted itself despite my efforts. I thought it was related to the heavy rain and cloud cover we were experiencing, so I gradually shifted my yagi around. No improvement. The only hair-brained thing I can think of is that there was a degradation of the microwave link from the dispatch location over to the simulcast ring. Since they are all using commercial grade equipment, they were not asking for repeats. But the 536 is not par excellence on digital decode, so it couldn't quite keep up. :rolleyes:
I also monitor frequencies < 150 so I don't think I can try a Yagi. Would a Discone antenna be better ?
 

cg

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Dec 13, 2000
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Connecticut
I would think it is within their system but the better quality radios make it decent enough where it can continue.
If you are getting part of a conversation from one user clear and the other user always poor on the same frequencies, an antenna change will likely not make a difference. Any chance that there is a non trunked frequency for them and part of the conversation is patched in? That would be odd but could happen.

chris
 

Ubbe

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Sep 8, 2006
Messages
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Location
Stockholm, Sweden
It has to be a system thing. If the mobile users are on a site that you monitor but the dispatcher are actually on another system and are patched to " your" system by some link that are not setup correctly, then you'll have that distorsion problem from the dispatcher.

I managed one system that used that technique while slowly transition from an old system to a new and the patch was of very poor audio quality that needed a lot of TLC until it gave acceptable audio quality.

/Ubbe
 

soberone14

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Nov 3, 2006
Messages
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Location
Spotsylvania,VA
Strange audio issue. The patrol cars come in very clear but the dispatcher is consistently garbled. Sometimes I can't really tell what they are saying.

Scanner: BCD996P2
Firmware: Latest
Antenna: included antenna with 40 Foot LMR400 cable mounted in the attic

Site: New Jersey Interoperability Communications System (NJICS)

Distance to tower: 2.14 miles, no line of sight

Talkgroup:
4915 1333 Te Oakland PD Oakland Police Law Dispatch

APCO Mode: auto
Threshold: 8
State: off
Hold Time: 0
Modulation: nothing set

I've scanned the forums and it appears either your audio is garbled or not. Not this problem, where only the dispatcher is garbled.
The Te means partial encryption. The dispatch is encrypted and the cars are not.
 

buddrousa

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Jan 5, 2003
Messages
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Location
NW Tenn
The OP started a new thread and was given his answer. Dispatch is Simulcast on both the VHF and TRUNKING SYSTEM the cars are no longer SIMULCAST on both.
 

mpagano

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Joined
Dec 23, 2019
Messages
7
It has to be a system thing. If the mobile users are on a site that you monitor but the dispatcher are actually on another system and are patched to " your" system by some link that are not setup correctly, then you'll have that distorsion problem from the dispatcher.

I managed one system that used that technique while slowly transition from an old system to a new and the patch was of very poor audio quality that needed a lot of TLC until it gave acceptable audio quality.

/Ubbe
Thanks everyone for your answers. You saved me some time and money that would have been misspent.
 

mpagano

Member
Joined
Dec 23, 2019
Messages
7
The Te means partial encryption. The dispatch is encrypted and the cars are not.
Would that actually be the case? I can hear the dispatcher and 'mostly' make out what they are saying. It's just has that 'marbles in the mouth' sound.
 

Ubbe

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Messages
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Location
Stockholm, Sweden
The OP started a new thread and was given his answer. Dispatch is Simulcast on both the VHF and TRUNKING SYSTEM the cars are no longer SIMULCAST on both.
OP has only posted 5 messages, all in this thread.

Does the dispatcher transmit on two simulcast systems but the cars are on a third system, and the OP's scanner are listening to the dispatcher on one of those simulcast systems and the scanner quickly scans to the third non-simulcast system when cars are transmitting? How are these three systems interconnected?

/Ubbe
 

maus92

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Annapolis
Would that actually be the case? I can hear the dispatcher and 'mostly' make out what they are saying. It's just has that 'marbles in the mouth' sound.
If you can understand the dispatcher at all, then encryption is not being used. Does the issue you are hearing happen with every dispatcher, or just one (or some) of them? If some dispatchers can be heard (more or less) clearly, it is likely a training or headset issue. If every dispatcher is distorted, it could be a console audio subsystem issue. P25 audio does tend to sound somewhat "warblely" at times, depending on numerous factors. Another possibility is how the dispatch center connects to the RF infrastructure. It is possible that the dispatcher uses a RF link / consolette (essentially a mobile radio) to connect to the system, and its antenna or cabling is damaged or out of adjustment.
 

mpagano

Member
Joined
Dec 23, 2019
Messages
7
If you can understand the dispatcher at all, then encryption is not being used. Does the issue you are hearing happen with every dispatcher, or just one (or some) of them? If some dispatchers can be heard (more or less) clearly, it is likely a training or headset issue. If every dispatcher is distorted, it could be a console audio subsystem issue. P25 audio does tend to sound somewhat "warblely" at times, depending on numerous factors. Another possibility is how the dispatch center connects to the RF infrastructure. It is possible that the dispatcher uses a RF link / consolette (essentially a mobile radio) to connect to the system, and its antenna or cabling is damaged or out of adjustment.
Thanks for the explanation. Yes it's all of the dispatchers and never any of the patrol cars. Someone mentioned this happens during a transfer to P25. I'm hoping eventually it resolves itself.
 

N1GTL

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Jun 14, 2005
Messages
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Location
CT
When the dispatcher talks, do you see the ID number on the scanner? Is the number always the same? It may be that each dispatch position is bringing up a unique consolette and the programming, levels or something else may be off with one position but not others. I listen to a system where the dispatch positions identify as 101, 102 and 103 and they are each different consolettes.
 
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Messages
66
Location
Beaverton, OR
I have a similar situation with the Portland (Oregon) Bureau of Emergency Management (BOEC) P25 system. Ambulances come in much better with error levels in the 8-10 range while the hospitals communicating with the ambulances on the same system pretty much fail to decode. There are three simulcast sites within line-of-sight of me, and I use a seven element yagi to try to offset LSM issues. I don't know if the hospitals are using actual radio transceivers to access the system or if their base stations are actually IP-connected into the system. Either way, I would think that I'm receiving the same transmitters and encoders that the ambulance transmissions are going through. Very strange issue.
 

mpagano

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Joined
Dec 23, 2019
Messages
7
When the dispatcher talks, do you see the ID number on the scanner? Is the number always the same? It may be that each dispatch position is bringing up a unique consolette and the programming, levels or something else may be off with one position but not others. I listen to a system where the dispatch positions identify as 101, 102 and 103 and they are each different consolettes.
I'll have to sit there and watch it. To be honest, it's in the furnace room and I have a semi-quiet town, so I'll have to carve some time out.
 
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