Modulation Levels?

[iMONITOR]

Why is it that fire communications (at least in S.E. Michigan) always seem to be over-modulated compared to police communications? There also seems to be a tendency for some firemen to feel the need to shout into their microphones, in addition to the radio over-modulating. That combination makes it almost impossible to understand at times. Don't these ultra expensive radios have some form of speech compression/limiting designed into them?

 

[Hoofy]

I hear that alot around here and I would guess it's because of the background noise and probably the ole adrenaline pump has kicked in. I have been in situations where equipment noise is so loud you couldn't hear yourself talking and so you tend to talk very loudly into the mic so that you can hear yourself and therefore you over modulate.


When you get several pieces of fire and/or rescue equipment running in close proximity the decibel level can get pretty high.

I don't know about the input limiting characteristics of these newer radios.

 

[Skud]

I hear the same thing here in Barry county on the MPSCS system. How loud they talk as well as how close they are to the MIC and which style radio they have. The Sheriff's dept office radio here is always bad no matter who talks on it.

 

[iMONITOR]

I'm doing some experimenting on controlling this at my receiving end. I'm using an Alesis Compressor 3630. It's normally a device for bands, and entertainers. It's a highly configurable audio compressor, or limiter, and I'm having good results with it.

I chose the rack mounted version, as my equipment is in a rack. But there are stand-alone compressors available.

Here is a picture of it. The picture is split in half for this post:

 

[iMONITOR]

After talking with Paul (KC8BDK), I should clarify something here. I'm not attempting to correct over-modulation with the Alesis compressor, but rather using it as an audio AGC (automatic gain control). It works quite well for leveling out the audio volume, by clipping what is too high, and bringing up levels that are too low, making it more uniform.

I'm not sure why Uniden hasn't been more successful in their attempts to correct this annoying problem.

 

[bigbluemsp]

There's nothing like a FF screaming into their mic while on the rig enroute to a call. The only one so far that I have heard that don't yell into the radio is the City FD here. All the others have mic to mouth and start a yelling like mad. Then again there is a city cop here that does the exact same thing on UHF.

 

[kc8bdk]

hehe... Then theres the other side of the coin... they key their mic and talk while its still on the mic holder, and its nothing more than a whisper.

 

[bigbluemsp]

hehe... Then theres the other side of the coin... they key their mic and talk while its still on the mic holder, and its nothing more than a whisper.

I can name a few local cops that are guilty of that.

 

[iMONITOR]

I once posted a comment in another thread that all public safety employees should have mandatory training on how to operate their radio equipment correctly. I caught a lot of flak about it...not sure why.

The radio is just as much a life saving tool as a gun, or a fire hose! Not knowing how to properly use any of these could be life threatening, rather than life saving!

 

[bigbluemsp]

The state mandates training to departments switching to the MPSCS on how to work their radios and such.