Well, maybe I was half-right. It appears that years ago,
AFSK did mean exactly what Ralph described with both AM and FM.

Today, AFSK has come to mean the use of audio tones to shift
the carrier frequency.

Sorry, and thanks for the opportunity to learn something
about changing customs!

73,

Chuck

chuck wrote:
Surely this is not correct. There is no conventional way of doing RTTY
on AM or FM.

The distinction between FSK and AFSK is that the former operates
directly on the transmitter's frequency-determining oscillator, while
the latter works first through the audio stages of an SSB rig to achieve
the same on-the-air signals.

Chuck

Ralph Mowery wrote:

"'Doc" wrote in message
om...

Ralph,
Works in SSB too...
'Doc



Doc, you must not have understood what I sent. When a ssb transmitter is
fed audio tones in to the mic input for digital modes such as rtty
you are
not using AFSK but FSK. It is AM or FM modes that feeding into the mic
input that you generate AFSK.

YOu do not normally generate AFSK by feeding audio into the mic input
of a
SSB transmitter, you generate FSK. If a single audio tone is fed into
a ssb
transmitter you get a single frequency output. If it is changed in
frequency you get another single frequency output. This is FSK even
though
you are using audio into the mic input.

If you feed a single tone into the mic of an AM transmitter , you get a
carrier on the frequency and two sidebands (upper and lower) of the
frequency of the tone. This is AFSK.