[GreenKeys] Re: GreenKeys Digest, Vol 11, Issue 9 Characters per line???????

[Ralph Mowery]

> Jan Bogue here with a couple of questions.
>
> I went on 20 meters this morning and listened to and copied three or four
> rtty signals.  I watched them on the computer program MMTTY to get a
feeling of
> what is going on.  When the signal seemed clean and tight, I turned on the
19
> set, and she copied the same as what was on the computer screen, good when
> good, bad when bad.  I was real happy with this, but what is the deal with
> characters per line???  One signal went across the screen and finally
returned after
> 90 plus characters.  The 19 set tries to figure this out as best as it
can.
> Another clear signal made a regular carriage return around the 75 mark
which
> the 19 thought was cool and continued to copy without a miss.  Is there
some
> type of mini characters per line war going on in the world of RTTY?  Are
there
> little RTTY habits I should look for?  Do the black rabbits talk to the
white
> rabbits, or do I have to act like the white or black rabbits when I am in
Rome.

> I went on 20 meters this morning and listened to and copied three or four
> rtty signals.  I watched them on the computer program MMTTY to get a
feeling of
> what is going on.  When the signal seemed clean and tight, I turned on the
19
> set, and she copied the same as what was on the computer screen, good when
> good, bad when bad.  I was real happy with this, but what is the deal with
> characters per line???  One signal went across the screen and finally
returned after
> 90 plus characters.  The 19 set tries to figure this out as best as it
can.
> Another clear signal made a regular carriage return around the 75 mark
which
> the 19 thought was cool and continued to copy without a miss.  Is there
some
> type of mini characters per line war going on in the world of RTTY?  Are
there
> little RTTY habits I should look for?  Do the black rabbits talk to the
white
> rabbits, or do I have to act like the white or black rabbits when I am in
Rome.

As others have pointed out you are noticing the differance between the
"glass" and the mechanical printers.  A mechanical printer will only do what
it is told to do by the incomming signals.  Some modles can be programmed to
do a few things such as the 28 with a mechanical box in called a stunt box.
The computers will usually do word wrap and start a new line.  Around 72
characters is the limit on the mechanical printers , then you must give it a
CR and LF to start a new line.  Sometimes it is not desirable to start a new
line such as overstriking for the PIX.  Overstriking is something a glass
screen does not do very well.

If you are sending on a mechanical machine you will almost have to send a CR
and LF around 72 characters.  When sending rtty you should send two carriage
returns, one linefeed and atleast one non printing character such as the
LTRS.   This may give some extra line feeds to the glass machines, but they
should be ok with this.   Usually when sending at machine speed by a  tape
you should send CR CR LF LTRS LTRS  without the spaces inbetween.  Two CRs
help incase the radio signals miss the first one.  The two ltrs help give
some extra time for the type basket to get back to the left on the older
machines.

Other things are some machines will unshift on space.  That is if you are
sending out a bunch of numbers every time the machine receives a space
character, it will drop back to the Ltrs.  So fi you send a few shifted
characters and a space , you need to hit the FIGS key if you want to send
more shifted characters..  On the modle 19  if you lift the flap above the
keyboard you can find the lever that will make it switch from unshift on
space to keeping the shift.   Also the shifted J and Shifted S are backwards
on some machines depending on the code used.  When making PIX tapes it is
common to send both the shifted J and shifted S.

About 25 years ago I wrote some code for an 8080 processor to run rtty with.
I had it set so it would look for a space after 65 characters when I was
typing from the keyboard.  If it saw a space it would automatically insert a
CR CR LF LTRS LTRS  sequence .  This would help keep from splitting a word
at the end of the line.  At 72 characters it would automatically insert the
end of line sequence.  The receiving side was set to emulate the mechanical
printer.  About all I could not do was a true overstrike.    As some that
are writing code now have not used the older mechanical machines, they do
not allow for the "problems" with the mechanical printers.  The glass
machine only takes a milisecond or less to go from the far right side of the
screen back to the left side.  The mechanical machine can take about 3
characters worth of time to do that. That is the reason for sending the LF
after the CR and a few LTRS characters.

While receiving print off the air keep one hand near the left side so you
can hit the lever to do a manual carriage return and also the line feed
crank.

YOu may want to go here and see if the CDs are still being sold.  Get the
one that has the years from 1963 to  1972.  That cd has much info about the
older machine and demodulators.

http://www.rjcdroms.com/