[arm-allstar] simpleusb-tune

Sun Jun 19 23:29:18 EST 2016

Bob,

 It certainly seems low but you are only modulating at 3 Khz deviation? 

Most people don't have test equipment or access to test equipment. Just use the simpleusb-tune-menu display to set the level from a radio that you know has its deviation set correctly. Talk into the microphone as you normally would and adjust the level to occasionally peak to 6Khz. Use iaxrpt's level meter also. That is a good indication. It should go up to 90% on peaks but not hit the top of the scale.

I have never checked it but I doubt the graphical level meter is that linear. 

For a simplex node you don't need test equipment to adjust levels. Use simpleusb-tune-menu and iaxrpt if you have it setup for RX.  Using test equipment for RX tells you little about what the actual radio(s) you are using will look like on the display or actually sound like. Also it does not matter what the TX level is FROM your node radio. As long as it sounds good to you, is not distorted and approximates the level you are hearing from repeaters or other services in your area it is fine.

Typically .1v P-P is more than enough at pin 21. Using a speaker output is not a good idea. First of all it is low impedance and it if effected by the volume control. You always have the possibility of accidentally changing the level. If an external point for high impedance audio is not available the best internal place is the high side of the volume control, a point where the control does not effect the level.

Also connect somewhere and ask how it sounds in relation to others. I would be glad to help if you want to connect to my node. Just let me know. This is NOT an exacting science and with the multitude of transceivers out there every one is going to be a little different. Thus you might have one that is really hot and another that has weak audio. If you use both you will have to set the levels at a happy medium.

73 Doug
WA3DSP
http://www.crompton.com/hamradio

To: arm-allstar at hamvoip.org
Date: Sun, 19 Jun 2016 20:09:34 -0700
Subject: Re: [arm-allstar] simpleusb-tune
From: arm-allstar at hamvoip.org
CC: k6ecm1 at gmail.com

Attempting to use simpleusb-tune-menu on a
BBB using a service monitor (3 kHz deviation, 1 kHz modulation). The output from
the radio (FT-1500M) is the speaker audio out of the back. It seems that full
volume (quite loud on the speaker) is not coming close to enough signal.

>From simpleusb-tune-menu

Please enter your selection now: 2

RX VOICE DISPLAY:

                                                 v
-- 3KHz        v -- 5KHz

|========>                                                                                           
              |

This is using 999. If this is linear, or
close, then I doubt the 2x gain amp will provide enough. I'm not sure what I've
done wrong. The input to URIx is pin 21, with 19 gnd. The iaxrpt level is about
2/3 max.

Any thoughts?

Thanks,

Bob

k6ecm

73

From: arm-allstar
[mailto:arm-allstar-bounces at hamvoip.org] On
Behalf Of Doug Crompton via arm-allstar

Sent: Monday, June 06, 2016 11:35
PM

To: ARM
 Allstar

Cc: Doug Crompton

Subject: Re: [arm-allstar]
simpleusb-tune

I
find that voice levels are highly dependent on the person speaking, the rig
they are using, the node radio,  and probably a dozen other factors.
Generally setting the audio so you see peaks just above 5 khz should be OK.
Some radios have better limiting than othesr and the peaks are well defined. On
some you can see peaks go well above what you would call max but the average is
much lower. One thing you don't want to do is have it set too high. Digital
distortion is very annoying. I often use iaxrpt's level meter for adjusting or
looking at multiple users for comparison. If you are filling the iaxrpt bar graph
to 9o-95% without hitting the edge you are good.

I often find that one node that shows 80% peaks actually sounds louder than one
that shows 95% peaks. Audio characteristics and equalization can play games
with your ears! I don't think setting using DTMF is always a good idea because
DTMF levels can be quite different than voice through the microphone. 

Some radios like the Chinese variety handhelds have greatly varying audio
levels depending on how far you are from the mic. You almost have to eat the mic
on some of them to have a decent level of audio and then you have breath noise.

If you use a wide range of radios that you use to talk to your node it is best
to check them all. You may have to come up with an average setting so that the
loudest radio does not distort. 

Talk into the radios the way you would when you are not thinking. If you adjust
it talking right into the mic and then when you aren't thinking you usually
talk 2 inches away the level is not going to be right.

In the future we hope to have audio processing capability added to the code to
help fix some of these problems. 

73 Doug

WA3DSP

http://www.crompton.com/hamradio

> To: arm-allstar at hamvoip.org

> Date: Mon, 6 Jun 2016 20:36:18 -0700

> Subject: [arm-allstar] simpleusb-tune

> From: arm-allstar at hamvoip.org

> CC: k6ecm1 at gmail.com

> 

> 

> What should I see as I change input audio levels? Is there a recommended
FM

> deviation? Is this the 3KHz and 5KHz? When I get it right, what should the

> display indicate?

> 

> Thanks,

> Bob

> k6ecm

> 73

> 

> 1) Select USB device

> 2) Set Rx Voice Level (using display)

> 3) Set Transmit A Level

> .

> .

> .

> 

> Please enter your selection now: 2

> RX VOICE DISPLAY:

> v -- 3KHz v -- 5KHz

> 

> Current setting on Rx Channel is 0

> Enter new value (0-999, or CR for none): 500

> Changed setting on RX Channel to 500

> RX VOICE DISPLAY:

> v -- 3KHz v -- 5KHz

> 

> _______________________________________________

> 

> arm-allstar mailing list

> arm-allstar at hamvoip.org

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> 

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> 

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