Question on Mountain Simulcast

W6DMM

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Mar 13, 2017
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Forest Falls, CA
I currently have a BCD996P2, and I understand how it may suffer with simulcast reception. My current issue is that I have the San Bernardino County P25 system programmed, with Forest Falls, Bertha Peak, Onyx Peak, East Valley, and Mountain Simulcast programmed correctly. I live in Forest Falls, and I can hear 2-CMD-4 and other talkgroups consistently, but I cannot pick up the 2-DISP-1 group with the AV paging on the Forest Falls system.

The Forest Falls group has 5 bars with good signal. For Mountain Simulcast, I have 4 bars but the system will never find a control channel, unlike with the Forest Falls group. All other systems mentioned above I cannot hit, presumably due to location.

I'm currently using a Tram-1089 for 800Mhz inside my garage, and a Comet CHA250B about 50ft up on my roof for all other frequencies and primarily CHP which works well. I've tried the Tram outside with no improvement in reception.

So my question is, what would prevent only the 2-DISP-1 from not being received while other groups are, and why can't I get a control frequency on Mountain Simulcast despite 4 bars? Thx!
 

officer_415

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Your inability to receive the Mountain Simulcast is probably due to simulcast distortion. Many scanners have trouble decoding P25 simulcast systems despite a strong signal, because they're receiving the signal from multiple transmitters. Some newer scanners like the SDS-200 handle it better. Since Forest Falls is a single transmitter, you receive it better.

As for not being able to receive 2-DISP-1, it could be that there are no radios on the Forest Falls site affiliated with that talkgroup. On trunked systems, traffic will typically be broadcast only on sites where there are radios affiliated with that talkgroup.
 

W6DMM

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Forest Falls, CA
Your inability to receive the Mountain Simulcast is probably due to simulcast distortion. Many scanners have trouble decoding P25 simulcast systems despite a strong signal, because they're receiving the signal from multiple transmitters. Some newer scanners like the SDS-200 handle it better. Since Forest Falls is a single transmitter, you receive it better.

As for not being able to receive 2-DISP-1, it could be that there are no radios on the Forest Falls site affiliated with that talkgroup. On trunked systems, traffic will typically be broadcast only on sites where there are radios affiliated with that talkgroup.
Thanks. Would simulcast distortion also prevent it from acquiring the control frequency, or just affect the talkgroups once it's acquired?
 

W6DMM

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Forest Falls, CA
Your inability to receive the Mountain Simulcast is probably due to simulcast distortion. Many scanners have trouble decoding P25 simulcast systems despite a strong signal, because they're receiving the signal from multiple transmitters. Some newer scanners like the SDS-200 handle it better. Since Forest Falls is a single transmitter, you receive it better.

As for not being able to receive 2-DISP-1, it could be that there are no radios on the Forest Falls site affiliated with that talkgroup. On trunked systems, traffic will typically be broadcast only on sites where there are radios affiliated with that talkgroup.
Also wanted to verify one thing on programming. The systems were transferred from RR, and it shows the SB County system as P25 Phase II, but the individual groups (such as Mountain Simulcast, Forest Falls, Onyx, etc) default to Phase 1 using FreeScan. Is this how it should be?
 

W6DMM

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Forest Falls, CA
I'm noticing that I am receiving groups from far outside my area such as Crossman Peak, Lake Havasu, etc. (I live in Forest Falls), but cannot pickup Onyx Peak or Bertha Peak. I'm trying understand how the system works and why this is so. I have all programmed to see if I can pull in 2-DISP-1. Thx.
 

tsalmrsystemtech

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Bertha Peak you can only hear this site in Big Bear area. Onyx Peak you will hear off the side of the mountain off of Big Bear on the Joshua Tree area and Palm Springs and Palm Desert Area

All the sites across the SBDCO system should carry 2-DSP-1 and 3-DSP-2
 

tsalmrsystemtech

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Update: I returned the BCD96P2 and purchased the SDS200. I'm now picking up the automatic voice paging system 2DISP1 on simulcast so it appeared to be an issue with the BCD/Simulcast as expected.
Oh yeah those BCD996P2 are not good for P25 Trunking 700/800 mhz Simulcasting systems at all. Horrible. Return that bad boy and get a Unication G5. Skip the SDS-200 or get both. One for the desk at home and the G5 for portability.
 

tkenny53

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what I found is best is to use Baker, east valley, and then the USFS SB radio, Cal fire in .your area, along with the local freq for BB and FF
 

f40ph

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Lots to unpack here...
Forest falls is a stand alone site, not part of the Mountain Simulcast. Are you trying to listen to both?
The RR database clearly says Phase I system.
 

W6DMM

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Lots to unpack here...
Forest falls is a stand alone site, not part of the Mountain Simulcast. Are you trying to listen to both?
The RR database clearly says Phase I system.
Correct. I was trying to listen to both, programmed in 2 separate systems. The San Bernardino County trunk system is Phase 2 but the sites themselves are phase one.
 

jrholm

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Given the geography of your location, I'm surprised if you get any sites besides Forest Falls.
 

W6DMM

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Given the geography of your location, I'm surprised if you get any sites besides Forest Falls.
What I still don't understand is that I can pick everything on Mountain simulcast, but only 2cmd4 on Forest Falls. Forest Falls shows as a single tower vs Mountain which uses a tower network. Is FF simply an extender with no affiliated other talk groups? Trying to understand how they work together and the purpose of how the FF tower fills in the valley but I can't hear the remainder of the TGs.
 

f40ph

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FF is a full trunking site linked back to the main core network via microwave. It's not only an extender for one talk group if that's what you're asking.
 

W6DMM

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Forest Falls, CA
FF is a full trunking site linked back to the main core network via microwave. It's not only an extender for one talk group if that's what you're asking.
Thx, no I'm trying to figure out why I can hear 2disp1 on Mountain simulcast but not the FF site when I'm literally .5 mile away. Only 2cmd4 comes through, not 2cmd3 etc or any Tac TGs.
 

f40ph

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The site will only repeat channels that are actually in use by a radio in the FF area. If you're only hearing 2cmd4, that means the only radio in the area is selected on that channel. Other TGs will not be rebroadcast by FF's site.
 
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