[GreenKeys] About a "Straight Key Night" for RTTY

[Jeff Stai]

hi Jim - This is from David G3YYD, creator of the 2tone RTTY modem
software, written earlier this year:

"2Tone will take PK232 200Hz in its stride. Each tone has its own AFC.
There are certain rules about this AFC. They cannot deviate more than 60Hz
from the set tone frequencies nor can they deviate more than 60Hz from each
other.

"So 2Tone AFC, when tones are set for 170Hz shift, will just manage shifts
between 130 and 230Hz. It will also cope with off frequency callers using
170Hz shifts by +/-60Hz. Deviation from the set shift will reduce off
frequency range."

I personally haven't experienced any problems with 200Hz shifts but I will
run 2tone along with the older MMTTY software as well as my venerable
ST8000. Maybe it's because I'm getting good results from 2tone I don't
notice the issue.

73 jeff wk6i



On Sat, Oct 27, 2018 at 7:49 PM Jim Haynes <jhhaynes at earthlink.net> wrote:

> On Sat, 27 Oct 2018, William Wuttke wrote:
>
> > Usually, if I could copy, I could make a QSO. However, there were a lot
> > of signals I could see on the waterfall, but could not copy. There are a
>
> One of the problems we have these days is that some operators are still
> using modems like the PK-232.  That box does RTTY and also AMTOR and
> Pactor.  Somebody made a bad decision that for AMTOR and Pactor they
> should use Bell 103 modem standards, which call for a shift of 200 Hz.
> RTTY traditionally uses 170 Hz.  With the PK232 the filtering is broad
> enough to receive either shift tolerably well, but more recent RTTY
> software has narrower filters and 200 Hz shift falls outside the
> bandwidth.
>
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-- 
Jeff Stai ~ WK6I ~ wk6i.jeff at gmail.com
Twisted Oak Winery ~ http://www.twistedoak.com/
Facebook ~ http://www.facebook.com/twistedoak
RTTY op at W7RN
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