FSK Keying with Kenwood TS-590SG

Discussion in 'Working Different Modes' started by KM6VEK, Sep 2, 2019.

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  1. KM6VEK

    KM6VEK Ham Member QRZ Page

    Hi everyone, first time posting on here.

    This question may have been answered in the past, I'm not too sure, but I couldn't find a clear answer.

    I've always wanted to get RTTY set up right, and so far I have been using AFSK configured on FLDigi. However, I've always wanted to try true FSK keying. I know the radio has an FSK mode built into it to narrow the passband for FSK, but I wanted to know how I could interface it to my computer for keying it. I already have a simple USB line running for cat control and audio. I also have a USB to Serial COM port for CW keying through N1MM. Has anyone ever done this before without buying a Rigblaster or Signalink? Thank you.
     
  2. KO6WB

    KO6WB Premium Subscriber QRZ Page

    Hi and welcome to QRZ....

    The operation of FSK is outlined in the manual.
    Here's what you have to check;
    Make sure you're using the correct separation of the Mark and Space. The default value is 170Hz.
    Check the frequency shift you desire. the default is 2175Hz.
    Connect the key to ACC2 connector pin 2. A ground at this point shifts the frequency.
    You'll need some type of device that can supply a key signal.

    The reason I haven't supplied you with the Menu # is because I have the TS-590S not the SG and the Menu # are different. The operation is the same.
    Oh and you'll need to put the rig in FSK mode by pressing the CW/FSK button. This also is outlined in the manual.

    Hope this helps
    73
    Gary
     
  3. WA9UAA

    WA9UAA Ham Member QRZ Page

    KB0MNM likes this.
  4. KM6VEK

    KM6VEK Ham Member QRZ Page

    Thank you both for your replies.

    What i did now was build another transistor circuit along with my cw keyer circuot, and outputted it to the ACC2 connector. I will be testing it out shortly
     
  5. KM6VEK

    KM6VEK Ham Member QRZ Page


    So i connected the ACC2 connector to my rig and tried loading up MMTTY two different times.

    First attempt:
    First of all, on the soldering side of the connector, it had the pin numbers, so i followed that. However, they didn't seem to appear right. When i looked up the pinmap in the manual, it was the reversed order. Anyhow, i continued. In MMTTY, i set the PTT & FSK port to the COM for the usb-serial adapter. I also set the Radio command port for PTT, which was set to the USB connection to my radio. When I tried sending my callsign, all that was heard through the TX-MON was the carrier. Nothing else.

    Second Attempt: Remember how I said the pins labeled could have been wrong? Well, I followed the manual this time. When I connected the ACC2 connector to the radio, it started keying it up and it was frozen. I had to disconnect the cable and restart the radio. So this attempt basically did nothing.

    Thank you.
     
  6. KB0MNM

    KB0MNM Ham Member QRZ Page

  7. KM6VEK

    KM6VEK Ham Member QRZ Page

    This is not exactly what my problem is. Those examples are for sending audio to the transceiver via a isb cable or soundcard. I'm having issues with sending FSK, which is keyed in dirrevtly to the radio
     
  8. KB0MNM

    KB0MNM Ham Member QRZ Page

    The last one *also* has to do with coupling the audio via a small transformer to isolate your source ground from that of the radio. This can set up ground loops, yet it usually ensures that there is no hum or differential voltage on your transmit input. The other end result is that the output of the transformer used for transmit can be relied upon to be somewhat representative of the signal you would expect as input to the radio. It could be measured as a small alternating current or sampled with a speaker. It is wise to use a selector switch for that purpose, not in parallel- rather either/or to keep impedance reasonably high. Your 590 manual should have information as to what is expected. There is also some pinout information for similar radios. I have found that some Digi-Key connectors have pin numbers which are easier to read than other vendors. Their P/N 839-1068-ND ( 13-pin ) would be one example. Were you using the ACC2 and bringing pin 2 to ground? ( as KO6WB suggested ). Many folks find working with the older Kenwood radios to be more of a challenge than others because active=high can sometimes be the expected case with other rigs. The business of 'true' FSK compared to 'simulated FSK' was explained some 10 or more years ago in QRZ magazine. If you are using a soundcard audio output, the FSK might be done on the card- which would not be the same as having a serial cable set to provide a keying signal only that allows the radio to provide FSK ( true case ). Your USB signalling may need to be passed into an RS-232 and/or TTL level converter to be appropriate for the radio. RS-232 levels usually reach +12 VDC and -12 VDC. TTL level signals are always either 0 or 5 VDC. USB signals can vary.
     
  9. KM6VEK

    KM6VEK Ham Member QRZ Page

    What i understood was that the TXD pin from the DB9 connector should be connected to pin 2 of the ACC2. Ground should therefore be connected to pin 12. Then, MMTTY will send the appropriate signals to the transceiver. However it's not, and it's only triggering the PTT from my USB cable.
     
  10. KB0MNM

    KB0MNM Ham Member QRZ Page

    Then we need to 'back the bus up'. If you wish to send out FSK, you need to make the radio or the audio source change frequency. Now the article that I read about the difference between true FSK and 'sorta' FSK implied that if you try to use an external audio signal, the radio may pass it- yet there is more chance for distortion. Thus the author would say that both work, but a radio which has 'built-in' FSK would be more likely to produce a signal read remotely by more receivers than one using a 'sound-card' input. You say that you can activate PTT, which means that MMTTY is running. The same suite of software has a version for FSK- but that is not labelled MMTTY, unless something changed recently. Looking further down the menu on the website, I did see a program which included FSK. Finally, you might want to realize that if a ground is requested- then a pull-up resistor ( to the appropriate voltage ) is generally necessary. So a common-emitter bipolar transistor circuit with a high-value ( say 10K ohms ) collector resistor is your means to key the PTT without locking things up. Yes, you do still need to consider the ground associated with pin2 of the ACC2 connector for keying. In your third post "second attempt", you said that the rig was 'locked up'. Does that mean you turned on PTT and could not turn it off? You could use a meter and a spare connector / cable to determine where the 'grounds' are, rather than buy one that is easy to read the pin numbers from.
     

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