[GreenKeys] Mark Question

[Harold Hallikainen]

On Fri, January 14, 2022 7:59 pm, W2HX wrote:
> Hi all,
>
> I'm still working on getting set up for RTTY at my QTH. I am planning to
> start with a glass tty set up, then get my M28s wired into the set up. I
> am using a 1980's vintage Harris modem that converts RS-232 to audio tones
> and vice versa. The way it is setup, when I type, I hear the mark/space
> transitions for each character. However, no audio is produced between the
> characters. Meaning no mark tone would be transmitted between characters.
>
> Question: How big of a deal is this when doing RTTY? I know that some TUs
> might not recognize that there is neither a space nor a mark audio
> frequency present, and may produce garbage on the screen/printer. Or, do
> most operators use a mark-hold function while receiving that would prevent
> (reduce) the garbage?
>
> Bottom line, should I go with what I have? Or work hard to make sure a
> mark tone is present at all times between characters?
>
> 73 Eugene W2HX
> Subscribe to my Youtube Channel:
> https://www.youtube.com/c/w2hx-channel/videos

It is standard to keep the tone up for the entire transmission. While a
lot of TUs (like my Flesher TU-170 https://w6iwi.org/rtty/tu170/ ) have
mark hold, it should not be relied upon to remove garbage between
characters. I wonder if there is a setting somewhere that would allow you
to do continuous tone or set a longer timeout (like the HAL ST-600
Keyboard Operated Relay).

Harold
https://w6iwi.org