The simplest way to insert a key into a mic/instrument chain is with a Cough Drop. You can buy boxes premade that are either momentary on or momentary off. Leaving two wires off of an XLR cable is a recipe for disaster in my opinion. There are even keyed microphones that are designed for pro broadcasting. Alternatively, you could just use what's called a "gate." This would cut any signal below a certain dB set by you. This is also a widely used tool in broadcast and live audio.

Now, most radio broadcast signals are compressed. Heavily. That happens at the radio station itself when it goes to the transmitter. If you are going out short wave or civilian band then you don't want a wide signal. Reproducing 20Hz-20KHz doesn't do you any good since you're only going to be using a band of about 100Hz-550Hz. Using the SM58 is a great place to start. Then you will want a compressor to tighten it up. You have to go gentle on the compressor at first because if you crush the audio too much it sounds like a$$. Also, be gentle with any make up gain because this is where most people screw up a compressor. They overload whatever is next in the audio chain and can't figure out why it sounds like garbage.

I would think you would actually be better off with some sort of stand alone processor rather than using Pro Tools and a USB interface full of latency unless you're trying to record the whole thing. There are boxes that have FX built right into them. So you would run your mic (keyed or with cough drop) into your interface/fx box and process the high and low pass, and compression, and then out to your broadcast device.

Thanks for your reply. I did a quick google search for a "cough drop" and it looks like that might work. It would probably vary radio to radio, some have different key circuits. but im sure it can be made the work. 2 wires off the xlr sound is not at all a great method, but thats what i was given as a quick option by others. ill try to look further into the "gate". Im using izotope and another plug in i forget the name with Pro Tools also. where i have utilize the gate provided to cut noise. "i found this useful for tracking down background noise. ie noisy pc fans hum from inverters and other equipment...

The main radio i intend to use this on unmodified will transmit 400hz-5000khz respectively. I cant say exactly the bandwidth it will be capable of once its expanded. But id expect at least a slightly wider ability after thats done. Not all other radios will be able to receive the full spectrum of what i intend to broadcast, but the definition is still there. Just because everyone else sounds like junk doesnt me i have to.

The session file i have has 4 channels each with an eq and compressor. a last channel with izotope alloy and the other plugin. id really rather share the file with someone to see what ive got, rather than explain. anyone else reading this is in this business and would understand more by looking at what ive got than me tring to explain it. anyone of you would most likely teach me something i dont know about what ive got, because i know very little. I decided to use pro tools being i already had a computer more than sufficient to run alone with protools by itself as a second computer. and the Mic mbox and software only set me back $150.

Once i put my shack back together from this sudden remodeling ill get to messing with pro tools more. i appreciate the tips. and any other input would be much appreciated!

By bandwidth, I meant the frequencies you will be needing as a speaker not what you are pushing on the airwaves themselves. The human voice has a pretty limited range of notes/frequencies it can utilize. No need to record the frequency of the top C on the piano if the voice can't sing or speak it.

well that sounds alittle over my head, or different from what i was told before. but id expect more accurate info from this place that the other sources ive looked at. So it leaves me a bit confused.

i was really beginning to think that i should figure out how to start a clean slate adding plugins as a go to try to teach myself what affect each one will impose on the sound of my voice. Being that i have not pro audio type experience or knowledge i really should learn something. I can make a car or home stereo sound choice, but thats like being the top student in a special ed class. but thats the extent of it.

Well you're confusing two things. There is the frequency range of what is going in the mic, and there is the broadcast range of your transmitter. These are not the same. You're used to thinking in broadcast frequency: 1093hz 1396hz whatever. You'll still be tuning your ham radio the same way but what I'm talking about is the other end of the deal-the gozinta end. All of that audio is converted to your broadcast format by your ham radio. Remy could probably explain it better in her special way since she did broadcast for NBC for decades. My radio experience by and large is dealing with AN/PRC radios and at the end SatComm and we weren't worried too much about audio quality. It just had to work.

If you will, just take a peek at this pdf. on the second page 1.1 for transmitter, the AM/FM frequency response 400hz-5000khz as being the audio "my voice" that is able to be processed by the unit and broadcasted lets just say 28.2850mhz. and same page under 1:2 Receiver, the Audio Frequency Response being 400-2500. im understanding this as being the the sound coming through the speaker that i hear as another operator. Not being argumentative just making sure were on the same page.
http://www.rangerusa.com/pdf/RCI298595DX_A.pdf
Im perusing through other threads on the forums just to try to piece things together to get a better understanding of things. so please bare with me.

You are still confusing the issue. The audio you record is a set of frequencies that are then formatted and broadcast by your radio. They are not the same. There is NO WAY your voice can produce 5KHz. Middle A on a piano is 440Hz. That's getting high for a male voice. The "a" two octaves below that is 110Hz and your voice would be severely stretched to reach that if you were a trained opera singer or had guzzled whiskey and smoked several cartons of cigarettes for years. You see what I'm saying? What you are recording is processed and then broadcast over a compact set of wavelengths. Let's say you are transmitting on 1390. Does that mean there is only one single pitch of audio (roughly F three octaves middle C) that's being transmitted? Obviously not since back in the day we listened to Basie and Nat Cole and Harry Carrey and they definitely weren't monotone. Paul Harvey for gosh sakes broadcast his well modulated voice for what....forty years?

Ok, i did some google'n and ive got an idea of what you mean now, i dont completely understand but i kind of get the jist of it. After more reading hopefully ill understand more. I on a whim posted on this forum hoping it would be a simple. but its a whole other ball park so it seems. Again thanks for your help.

Well, it really is pretty simple if you can make the connections and especially if you aren't concerned with latency. You just want thicker beefier vocals. Every singer wants the same thing only they're also usually screaming at the tops of their lungs. You're getting hung up in the theory. A simplified rendition:

Sound is made of vibrational frequency, but not all frequency generation produces sound. A shortwave radio EM wave itself is not audio sounds until it is decoded by a radio receiver and sent through a transducer (speaker).

Vibrational audio sound like what you hear with your ears is converted to electrical energy by a microphone or other similar device and then transmitted via cable to (in your case) an analog to digital converter (MBox) and into your DAW. Your DAW then sends the digital signal back out to the MBox and converts the digital audio to analog electrical signal and then out to (in your case) a short wave radio which then converts that electrical signal into EM radio waves.