[App_rpt-users] RTCM falsing DTMF

[Chuck Henderson]

//  My fix for the DTMF falsing problem is to make one change to the file
dsp.c
//  /usr/src/trunk/asterisk/main/dsp.c
//  Change this line in dsp.c (find the line by searching for 26.0)
#define DTMF_TO_TOTAL_ENERGY    ((digitmode & DSP_DIGITMODE_RELAXDTMF) ?
26.0 : 42.0)
//  To look like this line
#define DTMF_TO_TOTAL_ENERGY    ((digitmode & DSP_DIGITMODE_RELAXDTMF) ?
38.0 : 42.0)
//  The result for our 2 repeaters,
//  one on VHF using the USB fob,
//  and the other on UHF using multiple RTCM's,
//  is a reduction of DTMF falsing from hundreds per day to only 2 or 3 per
day and
//  no problems decoding DTMF.
//  I do not turn off RADIO_RELAX because doing so caused problems with
DTMF decode.
//  The only problem with my fix is that I have to re-edit dsp.c every time
I update.
//  Remember to do the usual "makes" after editing this file.


On Sun, Jun 3, 2012 at 4:01 PM, Tim Sawyer <tim.sawyer at me.com> wrote:

> First I would update from svn, might as well as you have to recompile
> anyway. The instructions to update from svn are at
> https://allstarlink.org/support.html#astupgrade
>
> Before you do the make up grade edit
> /usr/src/astsrc/asterisk/menuselect.makeopts
> change the line that says
>
> MENUSELECT_CFLAGS=RADIO_RELAX LOADABLE_MODULES
> to
> MENUSELECT_CFLAGS=LOADABLE_MODULES
>
> then do make upgrade or make upgrade-acid as appropriate.
> --
> Tim
> :wq
>
> On Jun 3, 2012, at 1:51 PM, Tim Sawyer wrote:
>
> I am one of those that found setting RADIO_RELAX off works much better. TT
> falsing has been reduced to near zero and decoding is still as fast as I
> can push the buttons.
>
> One thing I found was that I had to turn on the PL filter. Before I did
> that TT decoding was unbearably show with RADIO_RELAX off.
> --
> Tim
> :wq
>
> On Jun 3, 2012, at 12:48 PM, Jim Duuuude wrote:
>
> This has nothing to do with the RTCM. The DTMF receiver is the same one
> that is used in all the other
> channel drivers for the other types of interfaces also.
>
> When the app_rpt stuff was first being developed (10+ years ago), the
> default parameters
> for the DTMF receiver seemed too "tight" for radio use. There were a
> number of combinations
> that were found of receivers and transmitting devices (HT's mobiles, etc)
> that did not seem to
> work reliably with the parameters the way they were, so we developed the
> "RADIO_RELAX" set
> of parameters, which are more "relaxed" then the normal ones.
>
> As time has gone on, there have been cases where using these "relaxed"
> parameters have seemed
> to do more harm then good. I dont know if your case is one of those. If
> you wish to try, I suggest
> re-compiling Asterisk with the RADIO_RELAX compile parameter turned off,
> and see if you like it
> that way better. I can guarantee you that you will have less "falsing" if
> you do that. What I can not
> guarantee is that you will get all the "real" digits decoded reliably (if
> you do that).
>
> Jim WB6NIL
>
> ------------------------------
> From: adamson_alan at hotmail.com
> To: app_rpt-users at ohnosec.org
> Date: Sun, 3 Jun 2012 15:26:06 -0400
> Subject: [App_rpt-users] RTCM falsing DTMF
>
> ok, so is it normal for the RTCM to get false DTMF when voice is doing
> over the link?  I adjusted the RX audio so that the 2 lights were off
> with a 3khz tone generated from a service monitor.
>
> I see oh between 6-8 DTMF's detected over the voter channel during use….
> How do you fix that issue?
> Alan
>
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