On Oct 24, 2010, at 4:57 PM, Jim Spears wrote:

> I hear a single tone in the monitor and the P3 also shows the same thing.  

A microKeyer does not modulate the FSK keying signal unless the keyer is 
commanded to do so by the software that is controlling it.  If nothing is sent 
to the keyer from the controlling software, the keying pin from the microKeyer 
to the K3 will be in a constant Mark state (a single fixed carrier).

A standard convention in Amateur RTTY is to insert the Baudot <LTRS> character 
when nothing is typed.  This produces the familiar two tone "diddle" signal 
that you hear from RTTY stations when they are idling.   Among other things, 
the diddle provides a reference for the automatic threshold control function in 
the demodulator to work on in case selective fading causes the two tones to 
have unequal energy. 

However, the microKeyer by itself does not automatically insert these 
characters for you.  The software that is driving the microKeyer is the one 
that is responsible for inserting the Baudot <LTRS> characters when the "input 
buffer" is empty (i.e., when you are not typing).

If the software is doing the proper thing, you should see the green front panel 
LED on the microKeyer II flashing.  If the FSK LED on the microKeyer II is 
fixed in the on or off state, you might check if there is a "diddle" option in 
the software that needs to be turned on.

73
Chen, W7AY

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