Loading ...
Sorry, an error occurred while loading the content.

Re: TNC-X and Motorola GM900

Expand Messages
  • tallachetree
    I experienced simular problem with audio jack to TNC-x. I found if I simply did not push the plug in until it bottomed out that it works just find; but if you
    Message 1 of 5 , Nov 8, 2005
    • 0 Attachment
      I experienced simular problem with audio jack to TNC-x. I found if I simply did not push the plug in until it bottomed out that it works just find; but if you push it in all the way it grounds out or something.

      BobKF4FFN
      --- In tnc-x@yahoogroups.com, Ian ZL1VFO <zl1vfo@y...> wrote:
      >
      > > Date: Thu, 20 Oct 2005 11:42:37 -0000
      > > From: "la4bma" lars.molstad@e...
      > > Subject: TNC-X and Motorola GM900
      >
      > > Hello folks,
      >
      > > I hooked up my TNX-C with the Motorola GM-900 Mic-connector, and it
      > > was keying, and sending ok, but it wouldn't decode anything... So I
      > > hooked up a scope, and had almost no sound in, but when I disconnected
      > > the RX audio, I had plenty from the radio..
      >
      > > Solution: installed a cap between the radio speaker output and the RX
      > > connector - works really nice!
      >
      > > Think I will replace a lot of old TNC-2 clones with this one,
      > > including X-DIGI....
      >
      > > L@rs, LA4BMA
      >
      > Looking at the circuit of the TNC-X, it has a 100 ohm resistor to
      > ground as a load, and 10nF capacitor suppying audio to it's receive
      > filter circuit. You shouldn't really require a coupling capacitor
      > between the radio speaker lead and the TNC-X, not unless it's audio
      > output is in bridge mode and attaching a load to ground is upsetting
      > the audio output bias circuitry, or inadvertantly grounding an
      > output.
      > Seems a little unusual, that.
      >
      > -Ian ZL1VFO
      >
      >
      >
      > ___________________________________________________________
      > To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre. http://uk.security.yahoo.com
      >
    • la4bma
      Well, Mine works fine with the cap inline, and did not work without.... Another thing with Motorola radios is the PRE-EMPHASIS/DE-EMPHASIS pr channel config..
      Message 2 of 5 , Nov 12, 2005
      • 0 Attachment
        Well,
        Mine works fine with the cap inline, and did not work without....
        Another thing with Motorola radios is the PRE-EMPHASIS/DE-EMPHASIS
        pr channel config.. Must be enabled to get any data... Does
        something with the sound quality.. Probably the lower frequency
        tones...

        L@rs, LA4BMa
        --- In tnc-x@yahoogroups.com, "tallachetree" <kf4ffn@m...> wrote:
        >
        >
        > I experienced simular problem with audio jack to TNC-x. I found if
        I simply did not push the plug in until it bottomed out that it
        works just find; but if you push it in all the way it grounds out or
        something.
        >
        > BobKF4FFN
        > --- In tnc-x@yahoogroups.com, Ian ZL1VFO <zl1vfo@y...> wrote:
        > >
        > > > Date: Thu, 20 Oct 2005 11:42:37 -0000
        > > > From: "la4bma" lars.molstad@e...
        > > > Subject: TNC-X and Motorola GM900
        > >
        > > > Hello folks,
        > >
        > > > I hooked up my TNX-C with the Motorola GM-900 Mic-connector,
        and it
        > > > was keying, and sending ok, but it wouldn't decode anything...
        So I
        > > > hooked up a scope, and had almost no sound in, but when I
        disconnected
        > > > the RX audio, I had plenty from the radio..
        > >
        > > > Solution: installed a cap between the radio speaker output and
        the RX
        > > > connector - works really nice!
        > >
        > > > Think I will replace a lot of old TNC-2 clones with this one,
        > > > including X-DIGI....
        > >
        > > > L@rs, LA4BMA
        > >
        > > Looking at the circuit of the TNC-X, it has a 100 ohm resistor to
        > > ground as a load, and 10nF capacitor suppying audio to it's
        receive
        > > filter circuit. You shouldn't really require a coupling capacitor
        > > between the radio speaker lead and the TNC-X, not unless it's
        audio
        > > output is in bridge mode and attaching a load to ground is
        upsetting
        > > the audio output bias circuitry, or inadvertantly grounding an
        > > output.
        > > Seems a little unusual, that.
        > >
        > > -Ian ZL1VFO
        > >
        > >
        > >
        > > ___________________________________________________________
        > > To help you stay safe and secure online, we've developed the all
        new Yahoo! Security Centre. http://uk.security.yahoo.com
        > >
        >
      • Ian ZL1VFO
        Message 3 of 5 , Nov 12, 2005
        • 0 Attachment
          > Date: Sat, 12 Nov 2005 20:52:33 -0000
          > From: "la4bma" <lars.molstad@...>
          > Subject: Re: TNC-X and Motorola GM900

          > Well,
          > Mine works fine with the cap inline, and did not work without....
          > Another thing with Motorola radios is the PRE-EMPHASIS/DE-EMPHASIS
          > pr channel config.. Must be enabled to get any data... Does
          > something with the sound quality.. Probably the lower frequency
          > tones...

          > L@rs, LA4BMa

          The pre-emphasis may have more effect than what is obvious at first
          glance. This web page gives some idea of why...
          http://www.febo.com/packet/layer-one/transmit.html

          73
          Ian ZL1VFO





          ___________________________________________________________
          Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with voicemail http://uk.messenger.yahoo.com
        Your message has been successfully submitted and would be delivered to recipients shortly.