[GreenKeys] Nice old picture

[Kevin DeWitt]

Sure. In my garage, it's no big deal. I can pick one fork and use it for
all machines. But, if another station calls and they have governed motors,
or if a station with synchronous motors calls and my machines are too slow
(receiving) or too fast (transmitting) the messages will be garbled.

I'm a Model 15/19 nut and have 4 machines of this series. Two page printers
and 3 Transmitter/Distributors of those have governed motors. I have 3
tuning forks of the same frequency (supposedly), but they have slightly
different output at the same temperature. So far I have had no issues but I
can say for certain (the tuning forks) all read differently.

As long as the selector cam speed (on the receiving machine) is in unison
with the transmitted signal and can complete it's revolution by the next
transmitted signal, there shouldn't be a problem. The selector cam turns
1/7th faster to accomplish this. If the transmitted signal is slower, the
selector cam (on the receiving machine) just waits for the next signal. If
the transmitted signal is faster than the selector cam on the receiving
machine, the message will be garbled.

I guess the moral of the story is, all tuning forks are not created equal.

On Feb 11, 2016 5:56 PM, "Ralph Mowery" <rmowery28146 at earthlink.net> wrote:

> Could you explain why the tuning fork could not be used from one machine
> to another if they are the same type and speed ?
>
> As the shaft should turn at the same speed on all of them I don't see
> where the problem could be.  I have only played with one governed motor and
> 'tuning fork'.
>
>
>
>
> ----- Original Message -----
> *From:* Kevin DeWitt <kevin.dewitt at gmail.com>
> *To:* Howard Weeks <weeksh at att.net>
> *Cc:* Greenkeys <greenkeys at mailman.qth.net>
> *Sent:* Thursday, February 11, 2016 11:57 AM
> *Subject:* Re: [GreenKeys] Nice old picture
>
> To add to Howards explanation, the PE-77 power plant in the tactical
> teletype set is DC output, which eliminates the need for the RA87
> rectifier. The PE-77 will drive both the motor and loop (using a line unit
> and plug adapter). The thing I learned about the tuning forks is they
> aren't exactly the same so if you use the tuning fork from one set to tune
> another, your readings may be different. Not a huge deal but I spent an
> afternoon trying to understand why.
>
>
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