Automatic Gain Control

[poppafred]

I'm really enjoying the DMR upgrade but I have an annoying problem.

Some of the users of the local DMR systems are unbelievably LOUD. Everyone else is fine and most of the time, monitoring is pleasant. But I swear some of these guys have the mic shoved down to their tonsils!

Is there a way to limit extra loud audio without reducing the others, an AGC function?

 

[737mech]

AGC 536HP

Same issue with my scanner did you find a way to fix it? I just programmed a DMR and they are loud.

 

[JamesO]

I have asked on the forum an number of times about the AGC. I also question if anyone has ever found the AGC to actually work, I do not think it does. My postion is until someone can prove the AGC actually works, as far as I am concerned, it doen't. Maybe after the holidays I may be able to compare 2 536HP side by side with and without the AGC enabled??

Then I have also asked for clear and concise examples of how to set up the AGC and what each setting refers to and how it changes the ACG behavior. Even asked for something like a White Paper or overall description of the differences between the Analog and Digital AGC.

What I do know in the past the GRE/Radio Shack radios with AGC actually did work and made a difference. They also had only 2 states, AGC On or Off. Things get a bit more complicated when there is more than a single setting and poor documentation and/or no useful examples.

So far silence from Uniden!

 

[rumcajs_tr]

AGC does not work.

 

[JamesO]

Assume we will just have more replies like the one above?

If the AGC is vaporware, fess up or finish the programming behind it. I just ordered my 2nd 536HP which will be hear toward the end of the year. I plan on trying to program both scanners the same and running them off a splitter to the same external antenna and then play with the AGC seeings to see what, if anything changes.

Someone at Uniden knows if the hardware hooks are in the radio, and someone at Uniden could develop test firmware to verify, test and tweak the AGC performance.

 

[QwKiE]

AGC I don't believe is for the volume it's more for the strength of the signal and on my HP1 both of them it works fine.

 

[budevans]

AGC & AVC

Two years ago I bought my BCD436HP. The first thing I heard was a dispatch from the local county sheriffs department on the Cleveland P25 system. The dispatcher voice was barely a whisper (which I couldn't make out) and the deputy's voice in the field was booming to the point of causing the 436 speaker to splatter badly.

I had monitored the very same system on my GRE PSR-500 scanner without this extreme volume difference. I turned my 500 on and monitored the sheriffs TG. The difference between the 500 handling of the audio vs the 436 was astounding.

I immediately did a post on RR. What I saw when I browsed threw the posts was a large number of complaints about the AGC or lack their of. That was two years ago. I've never seen the issue addressed.

As another member posted, technically AGC back in the 1920's was designed to work on Analog AM RF signals to help control volume levels. Later AGC became considered part of the AVC (Automatic Volume Control).

Bottom line what everyone is looking for on digital system is really an AVC control. Which by definition is designed to keep the volume output within a defined range by boosting low volumes and reducing high volume sounds. Other designations are audio compandor or compressor circuits.

Regardless, it's been two years since my post about the audio dynamic range issue with Digital AGC. I've never seen it addressed. My work around is to used earbuds when in the field and at home I attach a cheap amplified PC speaker. The cheap ($7) speaker works really well. The overall sound is much better than the built in speaker, plus the amplifier seems to level out the audio to a comfortable listening level.

 

[budevans]

Work around, sort of.

Same issue with my scanner did you find a way to fix it? I just programmed a DMR and they are loud.

A band aid approach would be to change the volume offset for each TG. You can do this in Sentinel. The changes can be + or - 3 with the default setting as 0.

In Sentinel click on the Volume Offset for the first TG, change it to the value you want. Now right mouse click on that value and select Copy. Highlight all of the TG's you want to change and click Paste.

When you are done, write to your scanner.

 

[Ubbe]

The complaint releated to dispatcher and deputy in the field, on the same TG, had too much difference in audio level. It could be fixed if there where an additional volume offset setting for the ID. I have the same problem on many TG's, that some ID on the same TG are where loud and others only a whisper.

/Ubbe

 

[ButchGone]

Yep, AGC on my 436 & 536 is vaporware. Turning this setting "on" does nothing.
BG..