[arm-allstar] simpleusb-tune

[David McGough]

Hi Bob,

I'm not sure about the FT-1500M, but these days radios frequently have
class-D speaker amps and they can't have the "ring" of the external
speaker terminal shorted directly to ground (e.g.: URI pin 19).

If you have a small 1:1 audio isolation transformer, that might help 
between the external speaker jack and URI pins 21 / 19, assuming the 
problem is that the external speaker ground is "floating," from the 
radio's perspective.

Since the FT-1500M has a mini-DIN plug for TNC connection, etc., that 
would probably work as an alternative interface method.

Anyone know for sure about the FT-1500M external speaker plug and 
grounding the "ring" side of the jack?


73, David KB4FXC




On Sun, 19 Jun 2016, Bob via arm-allstar wrote:

> 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
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > 
> > Visit the BBB and RPi2 web page - http://hamvoip.org
> > 
> 
>