full duplex radios

i really need some help. I am looking for a full duplex radio where I can have three people talking to each other. they also need to transmit over 200 meters. Must be able to be carried in a pocket.
Is it possible to modify any radio to do this?:
My application is simple. I am trying to use it for a referee and two sideline officials. They must be able to talk with each other on an open mic.
Is there such an item?

Any help would be great.

It sounds like you are searching for radios for soccer referees (or possibly rugby). I have been researching the same topic, and while I donโ€™t have definitive answers yet, I have some information I can share.

You can contact me directly by visiting my website <link removed. See Forum Rules>.

There may be several options but a few things come to mind.

  1. Cell phones with headsets, and then use three way calling. That would give you open mic capability that you are looking for (ie: anyone can talk whenever they want without having to wait)

  2. Use a VOX (voice activated) headset with a two way radio. Here simply you have have to get three radios that are capable of communicating the distance and then equip them with VOX mics. Keep in mind some radios have the VOX capability built into the radio others would require a device that lives in between the radio and mic.

Additionally, and this is just a thought but I knew referees that used 2 wire mic systems to on field communications. Here they wore light weight FRS radios equipped with 2 wire mics to communicate with one another. A two wire mic consists of 2 wires one with the earpiece that runs up the shirt front of back, and a second wire that has the microphone that is run down a shirt sleeve to the palm/wrist so the ref can run and just activate the mic in his palm and talk into his had. (Think secret service/FBI style mics)

You are looking for a full-duplex wireless transceiver/intercom.

They are commonly used in theatre where all users must have split second access to all other users. There are some relatively inexpensive systems on the market that use the 2.4GHz shared frequency spectrum.

While it seems like a good idea for sports referees, there are some issues you should be aware of:

  • They consist of headphones and a belt pack. The headphones will block hearing to one ear completely and the headphones and belt pack can be lost easily during action, creating a HUGE hazard to your referees and players.
  • They are not as cheap as actual two-way radios.
  • They are bulky, and if a referee goes down and they fall on a belt pack, they will get hurt. (Never wear them in the small of the back!)

Personally, I would communicate the same way referees have done for a hundred years.

Iโ€™m not sure the OP understands what he is asking for.
Full Duplex is where you can both talk and listen at the same time.
The only option I am aware of is the telephone / cell phone.

Most radio operates under the function of half duplex, - I talk, you listen.
When two people talks at the same time, there is two transmitted signals on the same frequency - which would produce heterodyning - noise.

try Yapalong.
It is a cool 8-user full-duplex for referees.