[GreenKeys] WRU and SELCAL

[Bob Camp]

Hi

The motor start time should be about as fast with tube driven relays as 
with a solid state relay. If you are running an all tube setup then 
your receiver filaments are going to have to be on to hear the net come 
up. I assume the keying tube would be running off the receiver filament 
supply.

A fairly simple way to give stuff time to set up is to simply transmit 
dead carrier for a second or so at the start of the message. It may 
fool some auto tune tu's but most of them should be fine with tuning to 
a solid mark signal.

It's been a while since I ran 15/19's but the lack of CR padding always 
bugged me. From what I hear Creed's are even worse than 15's. I think 
what ever we do should at least be compatible with stuff WW2 stuff. I 
suspect the Lorenz TTY's had about the same response as a 15, don't 
know about the Russian stuff. Might be interesting to look into .....

	Take Care!

		Bob Camp
		KB8TQ



On Apr 26, 2004, at 9:30 PM, Tom Jennings wrote:

> I've been following this silently, I think it's great.
>
> I too agree that this ought to support old iron, and not get lost in
> "creeping featuritis". 60 wpm, carriage delays, last-four-character
> selcals, etc so it can be done in real stuntboxes.
>
>
> On Mon, 2004-04-26 at 16:43, Bob Camp wrote:
>
>> ... I think you are right about not wanting a TTY running
>> 24 hours a day to do this. I think the same thing applies to other
>> hardware as well.
>
> Teletype motor control would make living with a full-time teletype a 
> lot
> easier (on the human and the machine :-).
>
> For an iron-and-tube setup, there's a problem of delaying or padding
> until the motor is up to speed. I don't know how long it takes, 
> probably
> more than CR CR ... maybe an operational hack, rather than a change of
> protocol, would fix it, eg. you call a station twice, the first one
> wakes up the motor.
>
> (I've got a solid-state relay on my Model 28, I delay about 1/2 second,
> so I don't know how long is really needed. Seat of the pants guess is 
> 10
> characters or so, I'm sure others here know better.)
>
> For PIC or computer based TUs buffering isn't a problem of course.
>
> (It would be easy to make the motor on/off timer with a single 
> thyratron
> in vacuum-state logic.)
>