[GreenKeys] Wheatstone Tape setup 1930

[Jim Cooper]

On 12 Jul 2021 at 12:35, Harold Hallikainen wrote:

> I thought it was one position for
> dit and the other for dah. It allows
> for the same size hole to be used for
> everything. I was thinking along the
> lines of a player piano where the
> length of the hole determines how long
> the key is down. 

The keyboard perfs for prepping morse traffic 
tapes used a narrow paper tape with tiny feed 
holes down the center.  The same size hole is 
punched on the upper track as on the lower track. 

     o      o   
.................................................
     o             o

The first, with the two holes vertically aligned, is a dot; 
The second, with the two holes offset, is a dash ...  the 
top hole keys the 'key' or relay ON, it stays on until the 
lower hole turns it off. 

The tape reader and keyer by Boehme is a monstrously 
heavy unit, with a motor turning a round 'container' about 
an inch or so thick and diameter of about six inches (as I 
recall) and the shaft continuing on to the reader head.  
The 'container' ... I'm told...  was filled with mercury !! 
I guess you could call it an 'inertia wheel' ... as once the 
unit came up to speed, any small variation was smoothed 
out by the mass of the mercury spinning around. 

The reader head was not much different from what we 
know as the Teletype tape readers, except it had only the 
two pins and the sprocket drive wheel ...  the pins would 
come up, just like the do in the M-14 TD or the M-28 LXD 
and if there was no hole in the tape they got blocked and 
if there was a hole the pin continued up to close the 
contact. 

> I did a little work on a Bunnell pen
> recorder. This could be used to copy
> Morse, though I think the recorders
> used on radio circuits were more like
> chart recorders where the vertical
> displacement of the line indicated
> signal strength, and the horizontal
> displacement was time. I think this
> made it more readable through fades
> than a simple threshold and on/off
> marking of the tape would get. 

The morse receiving unit, widely used on the 
undersea cable channels when they were still 
used, was an even bigger monster ... especially 
weight wise.   Most of it was a BIG round roll, 
as I recall about 8 inches in diameter and maybe 
6 inches thick, wound with teeeeeny, tiny wire; 
so it's basically a very, very sensitive 'selector 
magnet' !!    This was needed because by the time 
the mark current got from one continent to the 
next, there was not much there ...  

As an aside, a while after I went to work in the 
M28 Lease area of ITT Worldcom in downtown NYC, 
I discovered that they still had the morse cable 
traffic circuit running to Havana ...  one day I went 
exploring and because I worked there they let me 
into the receiving room ...  the incoming channel was 
a very long narrow 'table' with the tape unwinder, 
the receiving coil and pen, and a tape winder to take 
up the penned tape.  An operator could sit there and 
read the tape as it came past, if they were very very 
good!, or the tape was taken somewhere for transcribing. 

I was told that when the cable was working well, they 
could run about 300 or 400 wpm continuously. 

At one time I had all the parts to such a system ... 
the keyboard perf, the Boehme base and reader head, 
and the receiving coil and pen recorder.  Some were sold 
off years ago; I know I still have two of the Boehme motor 
bases but I can't find the tape reader head for either of 
them; and I think the only coil I have now has the pen part 
badly damaged ...  as you might surmise, the pen part was 
VERY delicate. 

> It's interesting that the FCC
> distinguishes CW from data
> communications in part 97. Though
> there is a symbol rate limit for
> data communications, I do not see a
> speed limit for CW. It would be fun
> to try running CW at 400 wpm. 

I've heard that some of the hot-shots have done that, 
but probably with electronic keyers.  As noted above, 
it was not unusual to run the cable channel at those 
speeds when conditions were good.  

Jim  w2jc