DTMF problems

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fchrist16
Posts: 348
Joined: Sun May 24, 2009 12:23 am
What radios do you own?: Desktrac, XTL/XTS's & XPR's

DTMF problems

Post by fchrist16 »

I hope someone on here can answer this.

I have a VHF and UHF Spectra for ham. Our local repeaters have autopatch and I can dial in fine on my VX-7r. I have in the RSS DTMF option area 10 phone number's as *P(ten digit number). I have tried it as *(ten digit number) both with no results.

On a side note my MTS-2000 Flashport VHF radio refuses to start. I got a charger for it off ebay and the red light blinks but no charge.

Any ideas on either topic?!?

Regards,

-Frank C.
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kb4mdz
Posts: 282
Joined: Tue Oct 02, 2001 4:00 pm
What radios do you own?: Too many for the time I have.

Re: DTMF problems

Post by kb4mdz »

Can you hear whether you're transmitting DTMF tones out your radio? If so, do they sound OK? Or too soft, or too loud (overdeviated/distorted)?
fchrist16
Posts: 348
Joined: Sun May 24, 2009 12:23 am
What radios do you own?: Desktrac, XTL/XTS's & XPR's

Re: DTMF problems

Post by fchrist16 »

I haven't tried listening. I'll do that shortly and let you know the results. Although it doesn't bring up the autopatch so I don't think it's going through at all.

Regards,

-Frank C.
Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Re: DTMF problems

Post by Will »

Hi Frank,

I sent you an email on the charger asking what model number it is.

On the Spectras it could be the alignment and compensation is incorrect causing distortion of the DTMF tones. A common problem.

As kb4mdz says, do you hear the transmitted DTMF tones clearly?
fchrist16
Posts: 348
Joined: Sun May 24, 2009 12:23 am
What radios do you own?: Desktrac, XTL/XTS's & XPR's

Re: DTMF problems

Post by fchrist16 »

Will,

I sent you a reply. If you have IM it might be quicker as I am working with a few of my radio's now until later tonight.

To everyone else: The DTMF tones are working correctly. I press Phone>SCROLL to the number I want and press Sel once for the * and then again to dial the number but no luck

Regards,

-Frank C.
Jim202
Posts: 3610
Joined: Sun Sep 09, 2001 4:00 pm

Re: DTMF problems

Post by Jim202 »

You need to make sure that the DTMF tones coming from the transmitter are not into compression. The
decoding of the DTMF tones depend on them arriving at the receiver audio stage where it is picked off
from in a pure undistorted form. Even a tone twist can cause problems. To those that have missed
the meaning of tone twist in DTMF, you need to go do some homework.

Many people try connecting a DTMF mic right into the radio without turning the levels down. If your
using a hand mic to generate the DTMF tones, there should be a level adjustment someplace on
the circuit board. Find it and crank the level down to a point just before you can't hear it. Make sure
you are listening with a receiver on the transmitter output. Try the tone codes and see what happens.
Some where along the line of slowly raising the level output of the DTMF, you will find a spot where the
distant end decodes the tones. Keep raising the level slowly until you find the point where the DTMF
tones fail to decode. The back down the output level about 1/4 of the distance between the top
drop out point and the low point where it started to work.

If you have a service monitor to measure the deviation, you should find the transmitter DTMF tones
at a level of about 3.5 KHz max. Your normal voice should max out at about 4.5 KHz. to 4.8 KHz and
no more. Even at these level points, the repeater could be set way into compression, and you might
have to go lower.

On the Spectra, there are a number of software adjustments that all need to be done correctly. If
someone has got in there and messed with the settings, you may have to do a complete alignment
to get it all to work again. The DTMF signaling is done separate from the normal voice deviation.

Jim
fchrist16
Posts: 348
Joined: Sun May 24, 2009 12:23 am
What radios do you own?: Desktrac, XTL/XTS's & XPR's

Re: DTMF problems

Post by fchrist16 »

Turns out the autopatch on the repeater went down a year ago and no one was told.

I'm still unsure of it was working right. I heard the tones clearly on my 2M HT and my VX-7r now...

Will when/if you see this or the email drop me a line.

Regards,

-Frank C.
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