[GreenKeys] Re: GreenKeys digest, Vol 4 #61 - 13 msgs

[W8MAQ@aol.com]

Gil and all,

I would echo Roy Norris's input and endorse inclusion of the list below in priority order.

External unit
Half duplex
HV loop for 3 or 4 devices (machines)
Speed conversion up/down with adequate buffer
"Optional" CR-CR-LF-LTRS at 72 characters
 
73 Jim W8MAQ


In a message dated 2/25/2003 10:33:01 PM Eastern Standard Time, Roy Norris (greenkeys-request@mailman.qth.net) writes:

> Date: Tue, 25 Feb 2003 15:07:20 -0600
> To: gil smith <gil@vauxelectronics.com>
> From: Roy Norris <rnorris@charter.net>
> Cc: greenkeys@mailman.qth.net
> Subject: [GreenKeys] RS232 to Loop convertor for Dovetrons
> 
> Hi Gil,
> 
> Ok, thanks very much.
> 
> On the new  RS232 to loop converter project, I do hope you can do it with 
> speed conversion and a decent sized buffer.  I have just completed the 
> exercise of trying to find 60 wpm gears for several model 28's and they are 
> just about unobtainable now.  I finally got a set through Don House and the 
> NADCOM Museum.  I bought  several gear shifts but they were exceedingly 
> difficult to find (took me three months and each cost over $100).
> 
> On a recent eBay auction, a Dovetron unit with speed conversion went for 
> over $500 when ones without speed conversion were going at $150.  It just 
> shows how serious a problem finding gears for 60 wpm has become.
> 
> As I wrote you earlier, having the ability to optionally insert CR CR LF 
> LTRS starting at the 73 character would greatly facilitate the use of 
> mechanical RTTY  as so many of the computer programs today don't adequately 
> provide for it and, when they do, the operators don't use the 
> feature.  This would also require the inclusion of some sort of buffer as 
> well. Someone else mentioned adding a character counter but just a light 
> and an audible "beep" that would come on when you had typed 70 characters 
> or so would be a nice feature to have.
> 
> Think about the possibility of including a common SELCAL.  This would be a 
> great feature for a group of users who wanted to set up an RTTY group on 
> one specific frequency and have all the machines activated by a common 
> SELCAL.  Traditional autostart circuits are so prone to tripping by noise 
> and off frequency stations.  This would be a big plus for un-attended 
> operation.  Also great for un-attended copying of news if George is 
> successful in getting RTTY broadcasting approved by the FCC.
> 
> I would vote for the separate box approach to facilitate use with TU's 
> other than just the Dovetron.  Just connect to the Dovetron with BNC jumpers.
> 
> I would think provisions for connecting three devices in the loop would be 
> ideal:  TTY printer, reperf, and TD.
> 
> Half duplex would cover most situations since few, if any, RTTY QSO's are 
> conducted in full duplex.  A separate loop supply can always be used if 
> someone wants to type to a reperforator while receiving on the page 
> printer.  Alternatively, you could put two loops on the board, one keyed 
> from the RS232 and one not keyed and both running off of the same power supply.
> 
> Their is very little ASCII on the ham bands or shortwave bands hence the 
> low voltage, low current loop for the Model 33's and up would probably be 
> superfluous without a baudot to ASCII converter for those wishing to copy 
> RTTY.  However, the low voltage, low current loop would be nice for Model 
> 33 owners who want to drive their machines from their 
> computers..
> 
> Just my two cents :)
> 
> Thanks very much for undertaking this project.