Using MMTTY with FSK
The following was taking from the Yahoo MMTTY Support Group. Information presented
here mentions WriteLog but should be of help to any one wanting to use FSK.
For FSK troubleshooting:
Unlike the MMTTY stand-alone program, you must set the COM port
the interface is connected to in the Ports menu of the Rttyrite window.
For a better explanation of this see my RTTY Starter page 6 at:
If you have the Port setting in the Rttyrite window set to the correct COM port
the interface is attached to, then you have to check to see if the interface
itself is working. It's best to check this with an O-scope paralleled across the
interface output that goes to the radio's FSK input. To check what the waveform
should look like, refer to my "Getting Started on RTTY" tutorial and Diddles & Troubleshooting page http://www.aa5au.com/rtty_diddles.html. When you key MTTY with WriteLog (or MMTTY stand-alone), it will send a constant stream of diddles.
If you don't have on O-scope, you can do it with a regular voltmeter. With
everything in the idle condition, you should see some kind of floating voltage,
say 5 volts. Then key the transmit of MMTTY with WriteLog and you should see a fluctuation in the voltmeter. This normally tells you that your interface is working correctly, but doesn't prove it as well as an O-scope.
If that checks good, you have to check the FSK circuitry in the '570. Since the '570 does not allow you to "monitor" FSK transmission, you must monitor it with another receiver tuned to the same frequency.
With your radio in the FSK or RTTY position:
Take the FSK input lead and ground lead and keep them open. Key the transmitter
manually and listen to the frequency of the tone being transmitted. It will be
either a mark 2125 or a space 2295 hz. Now directly short the FSK input to the
radio to ground with the transmitter still keyed and you should hear the tone
shift 170 hz either high or low. Depending on how you have your FSK polarity set in the radio, an open may produce either a mark or space. A short of the FSK input
of the radio should shift the tone 170 hz. If there is no difference between a
short and an open, then the FSK circuitry is not working, but that's rare. I
had it happen to one of my TS870's once but that was after a lightning strike.
With AFSK, it's simple audio from the sound card to the audio input of the
radio. If you have audio coming from your sound card, then you should be able to
transmit AFSK with your radio in the LSB position.
Hope this helps,