Improving Quality of Feed ?

I'm looking into installing a compressor-limiter in my feeds. I've noticed quite a large variations in audio amplitude, maybe 20-25db depending on the specific channel on the radio, distance from person speaking to microphone, etc.

Like to get thoughts from those who've done this. It looks to me like there are two different approaches.

A hardware device such as :
Behringer: MULTICOM PRO-XL MDX4600

or software with virtual cable interface.

Thoughts??

Depending on the radio you're using, there are a few things you can try.

A quick look at the 'Biddeford and Saco Police, Fire, EMS' feed information shows the following example.

151.14500 WPJH418 BM 192.8 PL BiddefordOp1 Biddeford Fire Department OPS1 FM Fire-Tac
154.10750 BM 103.5 PL BiddefordOp3 Biddeford Fire Dept OPS 3 FMN Fire-Tac
155.66250 WQDC754 BM 141.3 PL BiddefordOp4 Biddeford Fire Dept OPS 4 FM Fire-Tac

Are they actually programmed as FM, FMN, and FM?
I would expect the audio on 151.145 and 155.6625 to be significantly lower than 154.1075 if they have been 'narrow banded'.

I suspect the mode for all of them should be NFM by now.

There are a few other things you can also try depending on the radio you're using.

Rich

Edit: There used to be one radio tech. around here who repeatedly adjusted the deviation very low.
I had to increase the volume offset in my Uniden scanners for that particular frequency until another radio tech. went in and adjusted it correctly.
The 'weak guy' is no longer around .. or ... he learned better.

On some of the P25 systems I had to max out the digital 'Reference Gain' to bring them closer to the analog volume levels.

Good suggestions, but

All set to FMn now...
Also, I've got the HomePatrol scanner AGC ON, AUDIO OFFSET to Max for the weaker channels.

Hence, I'm looking at other options?

k1xd said:

A hardware device such as :
Behringer: MULTICOM PRO-XL MDX4600

Click to expand...

Nice piece of hardware there... but maybe overkill. Check out this thread: http://forums.radioreference.com/general-scanning-discussion/295616-audio-compressor-scanner.html

I ordered the boards and all the parts to make a two channel unit, just haven't had the time to sit down with the soldering iron.

Its hard to compensate for low user audio, especially on P25 when the users don't hold the mic up to their mouth. I swear some users don't even take the mic out of the holder when they use it. I do believe that you can bring the audio signals closer together without affecting the quality of normal signals too much. I purchased a used Behringer compressor from ebay and I use it for my private feed. It is handy as I am always messing around with different audio sources. I connected the output of the compressor to my computer and adjusted the levels. Bottom line is a compressor can help but don't over compress. If you can get a good deal on a compressor give it a try, until you have a unit sitting in front of you hooked up it's really hard to know what it will do.

I hope this helps.

kb8zxe--

Thanks for the info. On my problem feed, the P25 is pretty good. The audio is pretty level. The analog channels though vary, sometimes 20db down from the P25 channels. I know with audio (or rf) you can't amplify and get something for nothing, but a 10-15db boost might work?

Which model compressor are you using?