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Re: [linuxham] True FSK support

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  • Jim Brown
    I don t think I saw any response that indicated a very simple way to generate a keying signal to input a key line to the FSK input of a transceiver. 
    Message 1 of 23 , May 28, 2011
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      I don't think I saw any response that indicated a very simple way to generate a keying signal to input a key line to the FSK input of a transceiver.  Remembering the days of using a Model 15 and later a Model 28 teleprinter, I used a very simple RTTY demodulator to extract a signal to operate a polar relay to key the loop to my old teleprinters.  Irv Hoff - W6FFC designed several demodulators - I remember him publishing the ST-4, ST-5, and the ST-6 demodulators in QST that convert the tones from a receiver to keying inputs for the loop supply for a teleprinter.

      Simplifying that type of demodular and setting it to the sweet spot you want to use for RTTY that matches your narrow filters in the radio, you simply feed the audio from the computer program into a demodulator and then use the output of the demodulator to key the FSK input to your rig.

      Some very simple RTTY demodulators were published in QST and in the RTTY Journal of yesteryear and with no noise to contend with, a demodulator for the audio output of the computer could be very simple.

      So if you REALLY want to your your FSK input on your radio, it is entirely possible to do so with a little effort to locate a demodulator to do the job.

      73 - Jim  W5ZIT

      --- On Fri, 5/27/11, Jeff Sumner <jdos2@...> wrote:

      From: Jeff Sumner <jdos2@...>
      Subject: Re: [linuxham] True FSK support
      To: "Linux Ham Mailing List" <linuxham@yahoogroups.com>
      Date: Friday, May 27, 2011, 10:59 AM


      My first experience in RTTY was similar- in the KG4AN shack in GTMO in the late 80's. We had a model 28 (66 BAUD- used to drive people CRAZY trying to tune us- but we didn't have any other gears!) running through the TS-530S.

      Loved punching the tapes and then loop-splicing them by simply hooking through the not-completely finished punches. Indeed: the model 28 was the Machine!

      Thank again, MVS on a 370 was fun, too. Computing as fast as cards could be read in… 3270's were too quiet, too.


      From: Andy <mm0fmf@...>
      Reply-To: Linux Ham Mailing List <linuxham@yahoogroups.com>
      Date: Fri, 27 May 2011 08:21:50 -0700
      To: Linux Ham Mailing List <linuxham@yahoogroups.com>
      Subject: RE: [linuxham] True FSK support


      (top posted 'coz Hotmail Web interface is wrong)

      Model 28 was THE machine.

      My introduction to radio (1973) was with a high school teacher who was a Teletype nut. So I was introduced to AR88+CV89a+TTY19 setup. We had some Creed 7B machines but they were grotty compared to TTY15 page printer or TTY14 typing reperforator. The 28 was just uber cool compared to the others. Only much later did we have a Siemens TT100 and Creed 444 to play with. The later machines were too quiet and didn't smell enough! So the 28 has been my favourite for nearly 40 years.

      RTTY on a PC holds no magic. No smell, no ker-chunk-a-chunk-a-ding-whirr-clunk!


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