BDC536HP Not Receiving Both Type 1 & 2 P25 Digital Transmissions

bwoodley

Member
Joined
Apr 12, 2010
Messages
9
Location
Salem, Oregon
I'm using this scanner to replace an existing older analog only unit so that our fire house can continue to receive the digital transmissions as we migrate from an existing VHF analog system to the nearby city's 800 P25 system. The specific system is the Salem P25 system in Salem, Oregon.

I've engaged the dealer and uniden support and neither were of any value. The uniden support person indicated - 'well, the SDS200 would be better suited to your needs.' Hindsight 20/20 - that's not what your website says. It says, 'scans APCO 25 Phase 1 and Phase 2, Motorola, ... as well as conventional analog and P25 digital channels'. I've imported the default template and manually entered the system information. The code plug and scanner have been sent back to the dealer and returned indicating - there's nothing wrong with the scanner or the code plug.

The units permanent home is about 5 miles north of the city itself so we're technically on one side of their system. My chief problem there is although my portable 2-way radio sitting next to it works just fine, both display great signal strength, the audio works fine on my 2-way but the scanner doesn't stop on a talk group and produce the exact same audio.

The thought that if their system is a simulcast system and having heard mixed commentary about how this unit either fails completely or has 'difficulty' receiving a simulcast system (after the purchase of course) is concerning. I've seen a couple of YouTube videos on how folks have implemented work arounds to cope with the simulcast problem. None of those seem to make a difference here. The physical tower location map provided by the radio tech shows the northern most tower should have 80% saturation or better over the next closest tower so it seems less likely a simulcast issue.

I have a known 'encrypted' police talk group enabled to work along side what is supposed to be non-encrypted P25 talk groups. To my amazement - I hear more garbled encrypted audio from the police talk group than I do the non-encrypted fire talk groups - GO FIGURE. Today I'm working from a different office in the city where I would believe I would have more problems with simulcast - and I'm actually getting more frequent transmissions from the fire talk groups, although the audio is horrible similar to that of a child's plastic CB toy radio.

The type of the system being a hybrid was described by the radio system technicians as, 'our system is a Linear Simulcasted in both C4FM (Phase 1) and QCPQSK (Phase 2) that operates dynamically between the two on each RF channel.' - Apparently this scanner has a hard time switching between the two types which complicates is it the system type or a simulcast issue. While I listen exclusively to just a few fire talk groups - and all those groups utilize the same unencrypted P25 digital format, the scanner shouldn't need to do a lot of switching depending on how listens for signals.

So my question to the group then becomes - can the physical location of the radio in relationship to a potential simulcasted system affect the performance of the scanner? If so, how?
Does anyone potentially see an issue that I haven't thought of or is there a programming parameter that may be of value? I have seen, System ID and Site ID values when observing the diagnostic 'System Status' but I'm not sure if that has anything to do with physical radio sites specifically. Has anyone had similar problems with the scanners not being able to actively switch between system types?

Any probing questions, tests to perform or advice greatly appreciated.

Brian
 

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Whiskey3JMC

Keep your friends close & your radios closer
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40.0417240450727, -75.23614582932653
I would indeed suspect simulcast distortion. Numerous cells transmitting the same traffic on the same frequencies at the same time can cause issues on a non-SDS series scanner & this is documented daily here on the forums. The link I provided should answer your questions & it gives some workarounds but they work in very few cases
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RFI-EMI-GUY

Member
Joined
Dec 22, 2013
Messages
6,845
Get a yagi antenna like this and point it at your closest cluster of sites. You can also use the front-back ratio to null out a site if an interfering one is behind your location.


You can always bring the scanner to a location close by a transmitter site to make sure the programming is correct, optimize the settings and then move back to your station and deal with the antenna if required.
 

hans_2

Newbie
Joined
Nov 22, 2012
Messages
2
Location
Dallas, OR
There is some missing information in the RR database that the BCD536HP needs. First, the band plan of the system. Also, I found that using anything but Custom 1 in the service type on the channels tab was hit and miss. Any channel that was labeled Fire-Tac just didn't work.BD339A31-DF1B-4426-9C15-32EA5DD37E3B_1_201_a.jpeg2C622E25-9848-46F5-A6DD-0C411B82AE2B_1_201_a.jpeg
 
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tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
9,126
Location
Baltimore County, MD
There is some missing information in the RR database that the BCD536HP needs. First, the band plan of the system. Also, I found that using anything but Custom 1 in the service type on the channels tab was hit and miss. Any channel that was labeled Fire-Tac just didn't work.
The band plan is not needed. It will automatically load from the control channel on a P25 system. Custom 1 service type is the default in Sentinel for any frequency or talkgroup that is missing the service type (tag). You will not receive any frequency or talkgroup with a service type (tag) of Fire Tac unless the Fire Tac service type is enabled in the profile. When you first install Sentinel, only the Dispatch service types are enabled. You must enable all of the service types you wish to receive.
 
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hans_2

Newbie
Joined
Nov 22, 2012
Messages
2
Location
Dallas, OR
The band plan is not needed. It will automatically load from the control channel on a P25 system. Custom 1 service type is the default in Sentinel for any frequency or talkgroup that is missing the service type (tag). You will not receive any frequency or talkgroup with a service type (tag) of Fire Tac unless the Fire Tac service type is enabled in the profile. When you first install Sentinel, only the Dispatch service types are enabled. You must enable all of the service types you wish to receive.

Thank you for the info! I was unaware of both!
 

JoeBearcat

Active Member
Uniden Representative
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Jun 30, 2020
Messages
1,843
that's not what your website says. It says, 'scans APCO 25 Phase 1 and Phase 2, Motorola, ... as well as conventional analog and P25 digital channels'.

But does it say the BCDx36HP supports simulcast systems? That is a completely different issue than APCO 25 Phase 1 and Phase 2, Motorola, Etc.

So my question to the group then becomes - can the physical location of the radio in relationship to a potential simulcasted system affect the performance of the scanner? If so, how?

Absolutely. Simulcast distortion happens when you are picking up more than one site and the data is not perfectly in sync.

Short of using a simulcast-supported scanner like the SDS200 (as was recommended by the dealer), you can use a non-simulcast-supported scanner if you restrict the reception to only one physical site. Do can do this by changing the antenna location or using an antenna that will restrict reception to a single site so there is no conflicting data to decode.

Your own image shows you have adequate signal strength but no signal quality.
 
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