[RTTY] MMTTY difficulties

[Kok Chen]

On Feb 8, 2013, at 3:51 PM, ham at n0sq.us wrote:

> A real motherboard serial port - not USB

So you are probably transmitting in FSK.

Did you check the baud rate of your UART and make sure it can be set to 45.45 baud?

Wrong baud rates usually result in some gibberish print, but you said there is no print at all, correct?  The most confusing part is that you are seeing no print at all even when the tones are centered on you KAM's tuning indicator.  Even with reversed RTTY, you will see some gibberish.  Not the complely silent output that you say you see.

A reversed RTTY sounds different from correct RTTY; wrong baud rate will also sound distinctly different.  Listen to a real life signal off the air and make sure the KAM prints properly, and listen again to the signal from your own transmitter -- do they sound pretty much the same?

When you turn diddles off,  does the receiver hear a single constant tone?  I forget now whether Mark is the right hand side tone or the left hand side tone on the indicator, or we can turn off diddle to confirm that you are inverted or not.  But, if you have good ears, the tone should be the lowwr of the two when you stop typeing with no diddles (and if your receiver is in LSB mode).

With the diddles turned off, do you hear an active RTTY tone pair when you start typing?  You might just think you are hearing modeulation before, with the diddles on.

Testing with diddles turned off might at least confirm that your typing is getting through to the UART.

73
Chen, W7AY