[arm-allstar] dtmf audio level

[Larry Mollica]

A couple of things…

Did you set RX and TX levels to spec per
https://wiki.allstarlink.org/wiki/Adjusting_USB_Radio_Audio_Levels  ??  I realize this can be tough for a lot of folks since it requires access to either a service monitor, or a modulation meter and FM signal generator, but it’s worth the effort. Unity gain is a good thing on networked systems. Ask around your local ham community, there’s probably somebody who knows someone with test gear willing to help. 


Getting de-emphasis wrong is a frequent cause of DTMF not working. Make sure that de-emphasis is being applied once, and not twice. If you are taking de-emphasized audio off the receiver, then your USB sound should be set to deemphasis=no. If not de-emphasized (i.e. raw discriminator) audio is used, then deemphasis=yes.

If double de-emphasized, RX audio will sound muddy, lacking highs.
If no de-emphasis in either radio or node, audio will sound tinny, no lows.
In either case, DTMF decoding suffers greatly.

Larry
AD6G


On Aug 15, 2022, at 12:24 PM, Don Sayler via ARM-allstar arm-allstar-at-hamvoip.org |HamVOIP| <7i5yut7hp95q5rt at sneakemail.com> wrote:

> Our node isn't recognizing dtmf tones. After doing a bit of experimenting,
> I have figured out that the audio level is too high and distorting the
> tones. But the voice audio level is fine. Is there a way to adjust the
> level of the dtmf tones individually? I didn't see one, and I'm not even
> sure how that would work. But I figured I'd ask the question...
> 
> Thanks.
> Don
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