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

FT-736R audio interfacing for WSJT??

Expand Messages
  • w6rqr
    I just acquired a FT-736R and want to hook up my homebrew audio interface that I was previously using on a IC706MkIIG. There is a PTT phono jack on rear for
    Message 1 of 5 , Sep 2, 2009
      I just acquired a FT-736R and want to hook up my homebrew audio interface that I was previously using on a IC706MkIIG. There is a PTT phono jack on rear for that function. The 6 pin DIN data connector is hooked to the FM modulator and demodulator NOT audio in and out. Any recommendations on the best way to hook up my audio in/out lines? Use ext. spkr jack and mic jack?? Any help is greatly appreciated. I am thrilled to have the 736!!
      73,
      Robert W6RQR
    • Paul Whatton
      Hi Robert I have a FT-736R here in the shack and have worked a lot of 2m FSK441 and JT65b using it to drive an amplifier with a pair of GI7b tubes. You should
      Message 2 of 5 , Sep 3, 2009
        Hi Robert

        I have a FT-736R here in the shack and have worked a lot of 2m FSK441
        and JT65b using it to drive an amplifier with a pair of GI7b tubes. You
        should be thrilled. It's a lovely radio despite it's age. It's a classic
        that is still sought after by VHF/UHF DX ops. At one point I had two of
        them and a friend of mine has five! Over the years I've collected the
        options as they have come up on ebay or at hamfests and now it's fully
        loaded including Mutek boards for 2m & 70cm, electronic keyer, 23cms and
        6m modules and even the voice synth :-)

        I used the mic socket for audio in, via an isolating transformer and
        attenuator. I've also use a home made soundcard interface which I plug
        the mic into and so can switch between the mic and computer audio.

        http://www.g4dcv.co.uk/interface.html

        For audio out I hooked up an external speaker and then tapped the audio
        from across it using resitive divider. Sorry I can't remember the values
        I used but a pot would allow you to get the balance between shack audio
        on the speaker and sound card input. It isn't the ideal solution but
        works fine although of course it isn't independent of the FT-736R volume
        control. I always meant to add a seperate audio out by bringing a line
        from the top of the receiver volume control pot to a phono (cinch)
        socket on the back panel, but I never got around to it.

        73 Paul G4DCV

        w6rqr wrote:
        >
        >
        > I just acquired a FT-736R and want to hook up my homebrew audio
        > interface that I was previously using on a IC706MkIIG. There is a PTT
        > phono jack on rear for that function. The 6 pin DIN data connector is
        > hooked to the FM modulator and demodulator NOT audio in and out. Any
        > recommendations on the best way to hook up my audio in/out lines? Use
        > ext. spkr jack and mic jack?? Any help is greatly appreciated. I am
        > thrilled to have the 736!!
        > 73,
        > Robert W6RQR
        >
        > __._,
      • K8TB
        If I may scream something here about the FT-736R. This rig rates as one the best overall radios ever made. Ever. But there is a serious flaw, and I exploited
        Message 3 of 5 , Sep 3, 2009
          If I may scream something here about the FT-736R.

          This rig rates as one the best overall radios ever made. Ever.

          But there is a serious flaw, and I exploited it.

          Inside the 736, the PTT lead goes right to the CPU. It is a 5
          volt pull up. If you ever apply +12 vdc by accident, you will pop the
          microprocessor. And there is no replacement. None. I spent hours on the
          phone across the country. The rig was locked up on 2 meter transmit. It
          worked, and you can change frequency, but the rig was toast.

          Quite frankly, if I would ever get another 736, I would put a reed
          relay inside it, to buffer that delicate PTT line. In my case, I had the
          PTT wired up to a packet TNC, and the TNC was getting its DC ground
          through the wires to the PTT connector. But the ground wire came off,
          sending 12 vdc in that microprocessor.

          So please be careful.

          Tom K8TB

          p.s., I parted out the 736R and did real well, the broken unit went for
          $ 250, and then the six meter module, the keyer and tone board went
          well, so I got some of the money back. But that incident smoked the
          microprocessor, and me!
        • Paul Whatton
          Hi Tom Sorry to hear this sad tale but many thanks for sharing your experience and knowledge. I use an opto isolator between the computer and PTT input in my
          Message 4 of 5 , Sep 4, 2009
            Hi Tom

            Sorry to hear this sad tale but many thanks for sharing your experience
            and knowledge. I use an opto isolator between the computer and PTT input
            in my homebrew soundcard interface. http://www.g4dcv.co.uk/interface.html

            Isolation inside the rig as you suggest would be even better. And yours
            is good advice not just for the 736R but I'm sure for many other rigs
            when used on WSJT or another soundcard mode.

            73 Paul G4DCV

            K8TB wrote:
            >
            >
            > If I may scream something here about the FT-736R.
            >
            > This rig rates as one the best overall radios ever made. Ever.
            >
            > But there is a serious flaw, and I exploited it.
            >
            > Inside the 736, the PTT lead goes right to the CPU. It is a 5
            > volt pull up. If you ever apply +12 vdc by accident, you will pop the
            > microprocessor. And there is no replacement. None. I spent hours on the
            > phone across the country. The rig was locked up on 2 meter transmit. It
            > worked, and you can change frequency, but the rig was toast.
            >
            > Quite frankly, if I would ever get another 736, I would put a reed
            > relay inside it, to buffer that delicate PTT line. In my case, I had the
            > PTT wired up to a packet TNC, and the TNC was getting its DC ground
            > through the wires to the PTT connector. But the ground wire came off,
            > sending 12 vdc in that microprocessor.
            >
            > So please be careful.
            >
            > Tom K8TB
            >
            > p.s., I parted out the 736R and did real well, the broken unit went for
            > $ 250, and then the six meter module, the keyer and tone board went
            > well, so I got some of the money back. But that incident smoked the
            > microprocessor, and me!
            >
            > _
          • Jose A. Amador
            I am going to be rude, and state that it is a cheap design in a high line radio, because it only takes one silicon diode in series to avoid it. Even better,
            Message 5 of 5 , Sep 4, 2009

              I am going to be rude, and state that it is a cheap design in a high line radio, because it only takes one silicon diode in series to avoid it.

              Even better, just use a buffer to burn instead of the rare and hard to replace CPU. But I believe the diode is enough. I use it in all my
              PTT line designs.Plain diodes in series with pulldowns help to isolate equipment in parallel hung PTT lines. I only use contact closing to ground
              or equivalent PTT. I believe it is universal enough. Of course,  any positive voltage closure to chasis ground.  Old  linears with AC relays are  something else.

              An optocoupler buffer is also a good measure I used one by convenience in a homebrew solid stete linear PTT line.

              In the FTL 2001 there is a shunt 6.8 V zener diode on the PTT line that helped once to protect the CPU.

              73,

              Jose, CO2JA
              ---

              Paul Whatton escribió:
              Hi Tom
              
              Sorry to hear this sad tale but many thanks for sharing your experience 
              and knowledge. I use an opto isolator between the computer and PTT input 
              in my homebrew soundcard interface.  http://www.g4dcv.co.uk/interface.html
              
              Isolation inside the rig as you suggest would be even better. And yours 
              is good advice not just for the 736R but I'm sure for many other rigs 
              when used on WSJT or another soundcard mode.
              
              73 Paul G4DCV
              
              K8TB wrote:
                
               
              
              If I may scream something here about the FT-736R.
              
              This rig rates as one the best overall radios ever made. Ever.
              
              But there is a serious flaw, and I exploited it.
              
              Inside the 736, the PTT lead goes right to the CPU. It is a 5
              volt pull up. If you ever apply +12 vdc by accident, you will pop the
              microprocessor. And there is no replacement. None. I spent hours on the
              phone across the country. The rig was locked up on 2 meter transmit. It
              worked, and you can change frequency, but the rig was toast.
              
              Quite frankly, if I would ever get another 736, I would put a reed
              relay inside it, to buffer that delicate PTT line. In my case, I had the
              PTT wired up to a packet TNC, and the TNC was getting its DC ground
              through the wires to the PTT connector. But the ground wire came off,
              sending 12 vdc in that microprocessor.
              
              So please be careful.
              
              Tom K8TB
              
              p.s., I parted out the 736R and did real well, the broken unit went for
              $ 250, and then the six meter module, the keyer and tone board went
              well, so I got some of the money back. But that incident smoked the
              microprocessor, and me!
              
              _
                  



              __________ Información de ESET NOD32 Antivirus, versión de la base de firmas de virus 3832 (20090206) __________

              ESET NOD32 Antivirus ha comprobado este mensaje.

              http://www.eset.com
              Untitled Document



              Participe en Universidad 2010, del 8 al 12 de febrero de 2010
              La Habana, Cuba
              http://www.universidad2010.cu
              www.universidad2010.cu
              ---------------------------------------------------------------------

              SEGUNDO SEMINARIO INTERNACIONAL LEGADO Y DIVERSIDAD. ARQUITECTURA Y URBANISMO.

              El rescate de los valores urbanos y arquitectónicos en tiempos de globalización

              Colegio de San Gerónimo, La Habana Vieja, noviembre 24-27, 2009

              ------------------------------------------------------------------------------------------------------------

            Your message has been successfully submitted and would be delivered to recipients shortly.