Multi Radio on one antenna system

[marczg]

I'm working on a in-building radio communication system and I want to use 2 or 3 mobile radios connected through one cabling/antenna system.
Is this possible to do using either a combiner or some sort of splitter? I need it be able handle transmitting and receive.
And is there anything I should be concerned about when doing this (power, signal loss etc.) ??

 

[mmckenna]

Are these radios all using the same frequency? Are they all different bands?

There are combiners that will do this, but the design depends on frequency separation, etc. There is a loss involved, and it can be 3dB or a LOT more. It's usually easier/better to just run dedicated antennas.

 

[marczg]

The radios will be on the same band (UHF). They need to be programmed with 6 frequencies that could be used as needed.
Its being installed in a hi-rise building with coax cabling and multi antennas placed strategically throughout the building.
So we are trying to cut out having to run extra cabling and antennas if its possible to do with one combiner etc.

 

[tlemke940]

you may need to look into using one radio and use a turn panel and remotes coming off of it that way all 3 locations can use the same radio. or you need to set up 6 radios (1 for each CH you want to use) with a combiner and have a turn panel on each connected to a console at each location. this can be done via copper or via IP depending on the setup you want to use. you might want to look in to JPS interoprability, Telex, and CPI. those are just a few but thay might fit what you need depending on setup.

 

[prcguy]

With all radios in the same band and wanting to use many frequencies within that same band the only cost effective way to do that is a separate antenna for each radio. There are ways to remote radios or to use filters or other methods but that would take some engineering and a lot of $$. Just install several antennas and keep them as far from each other as you can.

 

[mmckenna]

The radios will be on the same band (UHF). They need to be programmed with 6 frequencies that could be used as needed.
Its being installed in a hi-rise building with coax cabling and multi antennas placed strategically throughout the building.
So we are trying to cut out having to run extra cabling and antennas if its possible to do with one combiner etc.

A "control station combiner" would do that. But it's going to be expensive. And it really hits the power output. http://dbspectra.wpengine.com/specifications/VHF_and_UHF_CSC_(118-512_MHz).pdf

I agree, separate radios or a tone remote setup.

Or, one radio, leaky coax system, which isn't easy.
Or, WiFi/LTE radios and make use of what's already built out.

 

[KevinC]

A "control station combiner" would do that. But it's going to be expensive. And it really hits the power output

As evidenced by my stack of them from failed implementations. We always gave the customer credit for the combiner but wouldn’t take it back so I inherited them. 30 dB loss is just a tad too much.

 

[Project25_MASTR]

As evidenced by my stack of them from failed implementations. We always gave the customer credit for the combiner but wouldn’t take it back so I inherited them. 30 dB loss is just a tad too much.

But there are a few success stories. One of my local dispatch centers uses one for VHF consolettes (conventional resources to a nearby site) but if I weren't attempting to utilize directional antennas somewhere where there is already portable coverage I wouldn't even attempt short haul CSCs. Had a couple of long haul units work out pretty well in the past as well at a different dispatch center. If implementing directly to a DAS, insertion loss through a CSC may be negligible especially if line amps can be used on the DAS.

 

[Ubbe]

I used a hybrid combiner for 4 radios in the 400MHz band and it will reduce the signal a lot, 7dB, but much better than having several antennas in the room that pump their RF into headsets and other devices sensitive to RF.

I think it was $200 15 years ago and has to be available from most filter companies.

PHY-TETRA-4-FME-...

amphenolprocom.com

/Ubbe

 

[Echo4Thirty]

As evidenced by my stack of them from failed implementations. We always gave the customer credit for the combiner but wouldn’t take it back so I inherited them. 30 dB loss is just a tad too much.

Isnt the answer to use a 30db amplifier? /s

 

[mmckenna]

Isnt the answer to use a 30db amplifier? /s

Mo' swing, 10-4?

 

[prcguy]

Mo' swing, 10-4?

The combiner doesn't need an amplifier, it needs a modulator to make it wall to wall, tree top tall, so crystal clear your transparent.