[Elecraft] DATA A Reverse? AFSK A Reverse etc?

[Richard Ferch]

The K3, like every other amateur transceiver I know of, uses LSB for its 
RTTY-specific data modes (AFSK A and FSK D). This is the standard 
amateur convention for RTTY. Note that RTTY outside the amateur bands 
may be different; the choice of polarity for RTTY is an arbitrary 
convention which is not the same in all services. Regardless of which 
sideband the transceiver uses, if you are using software to decode and 
encode signals the software usually provides a way to choose either 
polarity.

The MMTTY software assumes the radio is in LSB. You can use MMTTY for 
amateur RTTY with the radio in USB (FSK D-REV or AFSK A-REV), but to do 
so you need to press the "Rev" button in MMTTY. Some multi-mode 
digital-mode software assumes the radio is in USB for all data modes 
including RTTY; there is usually a Reverse option in such software that 
you can use so the software will work with the radio in LSB.

As for CW, you can use whichever sideband you prefer (e.g. depending on 
whether you are tuning up the band or down the band, or on the presence 
of nearby signals either above or below the desired signal's frequency). 
The stations you are contacting cannot tell the difference. Be that as 
it may, the K3 uses LSB for CW; CW-REV in the K3 is USB.

73,
Rich VE3KI


K3KO wrote:

> Keep in mind what's "normal" depends upon where you are.  My
> recollection is that MTTY used to transmit on USB as non-inverted.   I
> think USB RTTY is standard elsewhere too.