[GreenKeys] Model 32

[Jim Cooper]

On 26 Mar 2021 at 15:07, E. wrote:

> I had thought - or have always
> understood that the rangefinder is
> for adjusting varied loop currents
> due to location and distance.  How
> can a TT properly print at motor
> frequency if the other side is
> sending it at a different speed (thus
> what the gears are for)?  The
> rangefinder canTMt compensate for that
> " or that much, can it? 

The original reason for the rangefinder 
adjustment was to compensate for slow 
rise-time or fall-time on the 'square wave' 
of each bit of the baudot code.  The waveform 
depended very much on the line capacitance, 
inductance and other transmission factors. 

However, a slightly faster speed (66wpm) means 
the individual code bits are 10% shorter; thus 
you would want the rangefinder closer to the start 
of each bit.  66wpm IS close enough to 60wpm 
that the rangefinder can adapt to it if the pulses 
are reasonably square (such as coming out of a 
TU or polar relay).  

As noted, sending is a different story.  If you are 
sending at 66wpm and the receiver has a 60wpm 
printer, and if their rangefinder is off-center to 
the 'late' end they might not get good copy on you. 

Jim  w2jc