[GreenKeys] WRU and SELCAL

Tue, 27 Apr 2004 10:44:36 -0400

Bob --

   My suggestion is to use "ZCZC" as the four-character code for all bulletins deemed by the sender to be of general interest.  The
ZCZC sequence is already at the start of ARRL bulletins, so it makes it somewhat easier to prepare them.  (I haven't checked to see
if the 5 SP 2CR 1LF sequence is present before ZCZC; if not, it would be easy enough to send.)  If someone else has a message of
general interest, it can be sent with ZCZC.  If someone is felt to be abusing the ZCZC general call, a little social engineering
should be adequate to address the problem.

   As you pointed out, we don't want too many selector sequences because there is a limit which can fit into stunt boxes.  If one
used all the features suggested by my previous message, one would have:
  3 SP CR - conditioning code.
  ZCZC - turns on printer.
  last 4 characters of your call - turns on printer.
  last 4 characters followed by Figs H - turns on WRU.  (I think this just requires function bars for the Figs H with the correct
pawls and such; one doesn't need to encode the last 4 characters of the call again if one is clever).
  CR LF - end of address code.
  NNN - end of message code.

   That seems like enough to get started.  Fortunately, a lot of these sequences are standard so one might find parts already
available for them.

-- Eric K3NA

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Bob Camp
Sent: 2004 April 27 08:15
To: [email protected]
Cc: [email protected]; [email protected]; greenkeys List
Subject: Re: [GreenKeys] WRU and SELCAL

Hi

There are two ends to the mechanical compatibility issue. One is on the
sending end the other is on the receiving end. I agree totally with the
idea that the receiving end needs to be mechanical compatible. On the
sending end I guess I have always assumed that you would punch up a
tape with what ever you need to fire things up on it. You could come up
with some kind of mechanical robot to do it all but that sounds like a
bit more work that it's worth. I don't remember any "real world" gear
out there that did the send end of the setup without using a tape. Of
course that may not mean a lot ....

If we go feature nuts on the sending end it just adds stuff to a tape.
If we go feature nuts on the receiving end that fills up stunt boxes
and it's a problem. I'm not really suggesting that we go feature nuts,
only that we need to look at which end of the process is impacted by a
given feature.

Here's an example: Maybe I'm into propagation forecasts. After a bit of
yack it turns out that there are others who have the same interest. Up
goes Bob's daily propagation forecast. I can send a long string of
SELCAL's (one for each guy who wants a copy) -or- I can send it blind
and you have to copy everything to get it -or- we can invent a unique
SELCAL for the thing.

All three approaches work. The first one with a long chain of call
signs is a pain to administer but it makes the receiving end of things
easy. The second approach also works and it's very simple, it just uses
a lot of paper. The third approach makes things like stunt boxes fill
up with extra parts.

If everybody invents a new "bulletin" SELCAL then we need stunt boxes
the size of a small car to keep up with everything.

In this case here's what I would suggest. Add a single feature - a
bulletin SELCAL. That way you can reasonably decide to get the
bulletins but not copy everything on the whole net. If we make it
something simple it should still fit in a more or less normal stunt
box. If we follow the bulletin SELCAL with a bulletin specific tag then
people with fancy setups can get more selective about which bulletins
to accept. In other words you keep the "feature" simple enough to work
on the receiving end and add a little to the sending end to do give us
full functionality.

I hope that makes some sort of sense. I'm not really going to get into
the propagation  bulletin business but it is a reasonable example.
Bulletins make good things for adjustment and test of setups. I think
they are something we want to encourage. I also think we want to do it
as simply as we can. I think we can come up with a pretty darn simple
system that also is very flexible if we work it out in advance. Tearing
into stunt boxes on a regular basis isn't a real good idea. There are
only just so many selector bars left in the world ....

	Enjoy!

		Bob  Camp
		KB8TQ