[RTTY] FSK is bad?

[Richard Ferch]

KI8W wrote:

> Then I guess I am the mercy of Kenwood, who built my TS-480sat. I am
thinking they did things right.

Unlikely. To the best of my knowledge, the only rig manufacturer who makes
a serious attempt to reduce key clicks in FSK is Elecraft (and even then
only after K0SM pointed the issue out). I hope someone like Chen or Andy
who really knows (not someone just knee-jerk defending their rig because
they have dropped a lot of money on it) will correct me if I am wrong.

KI8W also wrote:

> I have been using AFSK but I do not like the actual transmit offset (
based on the displayed frequency) when using LSB.

Your RTTY software should compensate for that. Any program that has CAT
control of the radio so that it knows what the dial frequency is should be
capable of subtracting the audio offset from the dial frequency and
displaying and logging the correct Mark frequency. Most RTTY software has
the ability to turn this offset calculation on (for LSB) or off (for FSK)
as the user chooses. In MMTTY this setting is in the Radio command window
under "Frequency offset". If you are running MMTTY under the control of a
parent program like N1MM+, the setting will be in the parent program. In
N1MM+ it's in the DI window's Setup menu - it's called AutoTRXOffset.

W6WRT wrote:

> MMTTY allows you to choose from many different tone pairs in FSK mode.
The difference is not really in the transmitter, its in the receiver.
For years I have used 1275/1445 because like Jeff says it sounds
better. The RF transmitted signal is exactly the same, only the
receiver is different.

No, the offset frequency in FSK is set by the transmitter. MMTTY can only
control the received frequency in FSK. Some transmitters allow you to
choose different tone pairs for FSK via a radio menu option, in which case
you can choose the one that sounds best to you. Regardless, you need to
ensure that your software (receive) and your transceiver (transmit) agree
on what tone pair you are using, otherwise your transmit and receive
frequencies will be different.

73,
Rich VE3KI