Do I have a DAS or BDA system??

[70cutlass442]

Do you know if most DAS are specific to a technology? We have a school that has a DAS for the 800MHz P25 system for the county, but the school's UHF radios do not work. If we setup a DMR system on 800MHz, would that DAS work or are they usually specific to a certain mode?

 

[Cameron314]

Unrelated to this exact topic, but still DAS related. Do you know if most DAS are specific to a technology? We have a school that has a DAS for the 800MHz P25 system for the county, but the school's UHF radios do not work. If we setup a DMR system on 800MHz, would that DAS work or are they usually specific to a certain mode?

Is it really a DAS or is it a BDA?

 

[70cutlass442]

Is it really a DAS or is it a BDA?

It would appear to be a DAS with cone shaped antennas in the ceiling every 200' or so.

 

[Cameron314]

It would appear to be a DAS with cone shaped antennas in the ceiling every 200' or so.

The shape of the antennas is not what makes it a DAS or BDA

 

[Project25_MASTR]

The systems are typically band specific.

 

[MTS2000des]

Also depends on whether the BDA is class A or B. A class A is typically what's implemented as it only amplifies and retransmits specific frequencies. Class B's are broadband and will pass anything within it's designed frequency range.

https://combausa.com/pr/class-a-vs-class-b/

 

[mmckenna]

How big is this school? How many buildings?

 

[70cutlass442]

How big is this school? How many buildings?

3 floors plus a basement. It is oddly shaped (long) and has numerous additions. We are going to try an 800MHz trbo system to see if the DAS passes the signal throughout the building. We will be in the same frequency range as what it is designed for. I am just curious if the tranmission mode matters.

 

[mmckenna]

A building that size could be either BDA or DAS.
DAS, I'd expect to see a head end somewhere. Maybe in a data closet, maybe with the fire alarm.
BDA's could be tucked in a closet somewhere.
Usually the door for where the equipment is placed is well marked, at least in our area it is by fire code. Maybe check near the fire alarm headend.

BDA's are mode agnostic, they pass what ever is in their frequency range. DAS could go either way depending on how it's designed.

DAS tend to be more expensive.

I'd bet you a donut and a cup of hot coffee that it's a basic BDA system that someone installed. I'll buy you a dozen donuts if it's actually up, running, well maintained, not in alarm, and not causing interference to someone.

 

[jhooten]

A building that size could be either BDA or DAS.
DAS, I'd expect to see a head end somewhere. Maybe in a data closet, maybe with the fire alarm.
BDA's could be tucked in a closet somewhere.
Usually the door for where the equipment is placed is well marked, at least in our area it is by fire code. Maybe check near the fire alarm headend.

BDA's are mode agnostic, they pass what ever is in their frequency range. DAS could go either way depending on how it's designed.

DAS tend to be more expensive.

I'd bet you a donut and a cup of hot coffee that it's a basic BDA system that someone installed. I'll buy you a dozen donuts if it's actually up, running, well maintained, not in alarm, and not causing interference to someone.

"We" have seven BDAs. The fire alarm panels are in the MDF room and the BDAs are in a separate IDF room. None of the rooms are marked to indicate the equipment is inside.

As to your last sentence, I am not looking forward to the day the warranty on them run out just based on the number of calls I've had to make for warranty service so far.

 

[mmckenna]

"We" have seven BDAs. The fire alarm panels are in the MDF room and the BDAs are in a separate IDF room. None of the rooms are marked to indicate the equipment is inside.

Must be a local code thing for us, then. The room has a sign on the outside. There's a large kill switch for it so the fire agency can easily shut it down if it's causing issues.

 

[Firebuff880]

@70cutlass442

There is a lot of good information here, but there is another thing to consider. Instead of DAS or BDA you could install a couple of Small Repeaters throughout the facility and link them together as a system. Moto's SLR-1000 is a good fit for projects like this.

 

[jhooten]

Must be a local code thing for us, then. The room has a sign on the outside. There's a large kill switch for it so the fire agency can easily shut it down if it's causing issues.

OR, the vendor that installed ours chose to save a few bucks and ignore code requirements.