[GreenKeys] Two very newbie questions

[Paul Heller]

Hey Joe. You are asking lots of questions and getting lots of answers. How about collecting all this into a document for “newbies”? Sort of an introduction to teletypes?

I could put it on RTTY.com. 

Paul
W2TTY

ITTY:			HTTP://INTERNET-TTY.NET:8000/ITTY
AUTOSTART: HTTP://INTERNET-TTY.NET:8030/AUTOSTART
EUROPE:		HTTP://INTERNET-TTY.NET:8040/EUROPE

> On Jun 18, 2019, at 7:50 AM, Thomas Tillson via GreenKeys <greenkeys at mailman.qth.net> wrote:
> 
> 
> Hi Gang:
> 
> First, where does the bell mount in a Model 28 ASR and where is it electrically connrected to?
> 
> The bell mounts underneath inside the bottom cabinet door. (See attached) A lot must be removed in order to install this correctly.
> 
> However, it may be mounted anywhere inside the cabinet in an unauthorized quick dirty fix in any place that is convenient.
> 
> The connections are 29-30 on the C block
> 
> ☠️ CAUTION this is 110 AC. Use proper precautions.
> 
> Tom WB2TTY
> 
> <IMG_0197.jpg>
> 
> In a message dated 6/17/2019 11:59:12 PM Eastern Standard Time, greenkeys at mailman.qth.net writes:
> 
> Hi Again!
> 
> Today has been a red letter day! First, I have got a line on a Fox Box! Yes, an honest to gosh electro-mechanical foxes generator. I hope that this works out. It will be neat to generate foxes without having to hand type and perf a tape. I cannot seem to type Quick Brown Foxes ten times in a row without a typo. Also, I received a brand new Model 28 bell for the ASR today, and several image tapes of Snoopy to demonstrate the capabilities of my teletypes. Thank you! You know who you are. I truly appreciate this.
> 
> Now, I have two very newbie questions even though I have had these machines for years.
> 
> First, where does the bell mount in a Model 28 ASR and where is it electrically connrected to? Google has not been my friend on this.
> 
> Second, back to a basic loop question. I have always thought of the loop as a current device... that is, when current flows, the selector electromagnets pull the little thing in and that is what starts the mechanical process of generating data. Now, is Mark when current flows and Space when there is no current?
> 
> Part B to the second question... I never thought of the loop being a voltage device. Yes, I know that there is a rather stiff voltage to push the current through the loop wires and electro-magnets, and that the loop must be energized. Now, I am studying the manuals for a FSK unit (military), and there are two options to key the unit: a) shorting two terminals together, which would require a relay in series with the loop; and b) by applying voltage from the loop on another set of terminals. So is the Mark considered "positive" and the space "ground state"? So this particular FSK device has two methods of keying, either shorting one set of terminals together (via a relay) or by connecting the TTY loop directly to another set of terminals, one being "positive" and the other "ground". Even though the relay set up is more complicated, I think that it would be actually easier to implement as I would not have to figure out what wire is "positive" and what is "ground".
> 
> Part C to second question... what type of relay should I use so that I do not bog down the loop?
> 
> Eventually, I want to have a regular um, "QSO" (with another amateur to keep it legal), but that anyone can listen to. I can "call him" on the air and "send him" the content, and he can respond at the end if he wishes, but it would be more like a bulletin. I have been talking with a friend of mine about this so that way, I can argue that it is not a broadcast, but a rather a QSO.
> 
> Any thoughts on any of this?
> 
> Thank all of you so much!
> 
> Best,
> 
> Joe KB0TXC
> 
> <IMG_0197.jpg>
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