Help monitoring multiple radios.

[Hacker]

Need a little help, so I'm coming to the experts. I am a member of a local tactical team, and need to be able to monitor and transmit independently on three separate radios. Radios 1 & 2 are HT1000's and radio 3 is a little black box job that uses a Motorola FRS headset jack. I really need to have it all feeding into a single earpiece/speaker and single mic boom with PTT buttons mounted in a box I can wear on my gear. I tried (and failed) to hack some speaker mics to a headset I already own, without success.

If anyone can build me a schematic / parts list, I can handle getting the parts and the breadboarding...

Thanks in advance.

[tvsjr]

You need to reevaluate your communications system, not try to cobble something together to talk on three radios. If you're getting shot at, the last thing you want to worry about is which TX button to punch. Plus, building such a device is going to require some time and effort - not something a member would scratch out on a cocktail napkin in 5 minutes.

I've worked with several tactical teams on various scenes. Without exception, they have always used a single radio, single channel, simplex. A commander on the outside should be handling all communications with outside agencies.

[Hacker]

I understand that, and am working on that too, but as the medic for the team, I have a responsibility to agencies outside the base team which is why I'm getting so little backup from the admin. If it's too complicated, guess I just keep the EMS radio stuffed in my pocket like I've been doing.

If I ever figure out a working solution, I'll post it here for future reference.

Thanks.

[wavetar]

Mixing, or summing the RX audio from 3 radios wouldn't be that hard. With a bit of time & effort, and possibly a 9-volt battery, a nice little box could be made. There are various mixing circuits, varying from simple passive to more complex active, here:

http://www.freeinfosociety.com/electron ... php?id=728

http://www.all-electric.com/b&c.html

The addition of a common TX audio & 3 separate PTT circuits integrated into the box would be more challenging. Many seasoned techs could certainly do it, however the time, money & effort involved to make it look good, easy to connect, wear & use, along with a high reliability factor, make it not so worthwhile.

Please note I don't recommend home brewing anything like this for public safety applications, just wanted to point out from a technical standpoint it can be done, but not by the average joe. Hell, not even the average tech these days.

Todd

[EPC_1111]

hacker if you are carrying 3 different radios AND on the entry team, you are doing it wrong. Your priorities as a tactical medic are 1. the team 2. everybody else 3. (if it is part of the mission) the bad guys

TVSJR makes an excellent point, if you are doing some sort of cop thing (or anything where you have more people as backup or who you want to have a heads up when you decide to have a friendly shootout) they need to be on the same channel. That is why we have NLEMARS and the I Tac and V call and Tac and U call and tac and OSSCR and CALCORD and CLEMARS and NASAR and TEXAS LAW, so EVERYONE can jump on the same frequency.

Do your job on the team (officer safety first) and when you do get around to actually shooting someone and using your emt skills, since you will do that once the threat(s) are neutralized, tell the CP that you have one ________ down and need additional medical support.

[High_order1]

Another point I haven't seen covered:


When you are doing your thing, the LAST thing you want is multiple radios AND your surroundings AND your team AND the suspects all talking at once. Oh, and your personal phone and your department batphone ringing, too. With nextel chirping.

The most I have ever tried was two radios, and it was too much for me. Best thing to do is wire yourself into whatever the team talks on, and like you say, pocket the other two.

I realize it seems like it would just be easier to have three buttons, but trust me when I say, simplify your life as much as you can.


-Shawn

[High_order1]

they need to be on the same channel.

Not to sharpshoot, but, no.

The only people on the entry team talkgroup needs to be the entry team and everwho stays behind to quarterback.

There needs to be an incident (what the hosedraggers call fireground, I think) meet me channel so that they can all give intel in, and recieve marching orders from, but I promise you, if everyone is tasked to a single channel, one longwinded mf'r not even in sight of the objective will render the system useless. BTDT


"can anyone give me directions to the scene?" lol
-Shawn

[Hacker]

I appreciate all the feedback. I have taken it to heart, and sat down with the team leader and we've switched the radio setup around to stream line it. Thanks for all the great comments!!

TH