[GreenKeys] Re: Just a few RTTY basic questions and a holiday thanks to all

[John Lawson]

On Thu, 25 Nov 2004 Russmill47 at aol.com wrote:

> John,
>
> Have you checked your Model 19 to see how many points of range your machine
> does have?
>
> You should have 80 point of range for a properly adjusted machine. If you
> haven't run this test yet (it may be covered in the books you already have
> received), run this test.  If you can't find this reference, send me a note  and
> I'll post the process.


   Just for grins, I looked up the range-finder setting procedures in TM 
11-2216 - it simply says to recieve RYs, then find the midpoint between 
errors on the low end of the scale and errors on the high end - with the 
way my current 19 is adjusted, this mid-point falls on about 45. Now - I 
have not revisited the selector magnet armature springtension adjustment, 
it was last set 'by eye' - using my old QBF test set.

   So it now becomes clear that I should oughta sit down one of these dark 
snowy evenings and just go thru the machine By The Book, then maybe it'll 
be capable of the higher speed ops - TM 11-2216 actually covers this 
too...

   Woo Hoo! I'm learning...!  ;}

Cheers

John  KB6SCO

PS: One goal for the mechanical machines is to be able to read and post to 
this List via the Model 19 or 28...  I have the Stuff, just need to find 
time to hook it up, squish any bugs, and see how it prints.







>
> The reason that a 45.45 baud machine can copy a 50 baud signal by
> misadjusting the range selector to the lower end of the range:
>
> There are three types of data transmitted in a character (a printed
> character, lrts, figs, cr, lf, etc.):
>
> Start pulse  -  in both 45.45 and 50 baud transmissions, the  pulse length is
> 20 milliseconds.
> Data pulses - in both 45.45 and 50 baud transmissions, each of the five  data
> pulses are also 20 milliseconds in length.
> Stop Pulse - here is where the difference occurs!  In 45.45 baud
> transmissions, the stop pulse length is increased to 32 milliseconds. In 50 baud
> transmissions, the stop pulse is also 20 milliseconds -- just like all of the  other
> pulses.
>
> When you lower, and misadjust the range selector on your Model 19, you are
> compensating for the shorter stop pulse length.
>
> I've done this with Model 19s that I've had in the past as well as my
> current Model 28.
>
> I hope this detail and the recommended test will give you the information
> you need to accurately copy the 50 baud signals that you will find on the  air.
>
> 73,
>
> Russ
> WA3FRP
>