[arm-allstar] Is there a quick and dirty how-to, on how to get your rx tx levels in the right ballpark...

[Doug Crompton]

I have setup many nodes without using test equipment. For the most part the
level bar graph in the simpleusb-tune-menu screen works. The real problem
is the difference in audio levels of the input device, the transmitter you
are using to talk to your node. They are all over the place and most are
not easily adjustable. Couple that with the noise cancelling mics on
handhelds and people who like to hold them 3 inches or more from their
mouths.

About all you can do is sample every radio you plan to use with your node
and make sure the highest deviation one is not clipping. I usually set them
to peak just above the 5Khz mark on the bar graph. Another way that works
well is the iaxrpt level bargraph. I find that to be very accurate. Set to
no more than 95% of full scale as once it starts hitting full scale and
beyond it will clip.

Another issue is perceived level vs. actual level. Some voices just come
through better than others. This is due to equalization problems and the
actual voice. They may look the same on a level meter but because of the
spectrum differences sound very different in level. This becomes more of an
issue on a public node or repeater where there are many different users.

A compression scheme as well as auto levelling would certainly be helpful.
We are looking at both for the new audio channel driver. For now the most
important thing is to not clip (have the level too high) and make sure you
consistently talk into the microphone in the same way as you set the level.
I always say to someone when I am setting their level to talk the way you
would when you are not thinking about it. Connect to a busy hub and have
someone compare your audio to others and don't be too concerned about
subtle differences.


*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*




On Thu, Aug 3, 2017 at 3:10 AM, "kd4ont via arm-allstar" <
arm-allstar at hamvoip.org> wrote:

> Without thousands of dollars of test equipment? I listened to my rx audio,
> on the target repeater. I did not set the levels. It was beyond my ability
> at the time. My audio, according to usb tune rx levels, was going past the
> max value. Granted, it gave me a very loud and commanding audio level,
> being too loud, compared to other audio, made me decide to break out the
> golden screwdriver and turn my fob levels down.
> I first set rx tx levels to midrange 500. Then i got my lowest audio level
> ht out. I hooked up to a very busy node with a *2node command. My audio
> would not pass. I have 2 tx hts. One has more low end, less upper, and less
> agressive agc, plus it has "noise cancelling" characteristics from the mic.
> A baofeng uv-82hp, with the mic hole slightly drilled out mod. I also have
> an Alinco dj-500 (new) with the same bigger mic hole mod done. The alinco
> seems to have less low end and a more agressive agc, but is so sensitive,
> it can hear a frog farting underwater.
> I used the 500 as my test level setting radio. I *2'd into the node, and
> made all kinds of racket, while trying to get my peak level at 5k. My uv82
> drives the audio harder during tests. I discovered my tx A level was jacked
> up to 999. I set it at 500, then gave the pot on the fob an ever so slight
> increase.
> Have I figured out level setting without having deviation hardware? I know
> I'm not clean, but I'm not as loud as I used to be. I'm not a wide area
> repeater. I'm a personal, 1 mile max portable moble node.
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