--- In [email protected], Nate Duehr <[EMAIL PROTECTED]> wrote: > > > On May 18, 2007, at 12:27 AM, wb6ymh wrote: > > > Your earlier messages struck me as "my favorite controller doesn't > > support site prefixing so site prefixing must be > > wrong/useless/stupid". This message just confirms it. > > Get a sense of humor or learn what emoticons are, please. Then re- > read the e-mail.
I know what emoticons are. Dropping them on the end of a flame is much like telling a racist joke and then saying "I'm just kidding" at the end. > > What Ed was trying to describe to you is not some whacked out idea he > > came up with off the top of his head but rather a fairly standard way > > things have been done for literally decades. > > So? And again, why do I need to care? > > Just because "everyone's always done it" doesn't mean it makes any > sense. Hopefully you have something more interesting to add to the > conversation than that? > > Seemed like a pretty good conversation to me. I'm still waiting to > hear back from someone about why this feature is important, since I'm > generally curious. Or why users need to command remote repeaters. > How often is something like that really used? So which is it, you don't care or you are generally curious? Ok, I'll take a whack at some history that may help you understand where this site prefixing concept came from and why. Hopefully I don't screw it up too badly as I was just a high school kid at the time who was in major awe of the wizards. The site prefixing scheme originated in the days of TTL control systems long before microprocessor based commercial systems existed. My understanding is that Alan Burgstahler, WA6AWD, originally conceived the concept in the very early days of repeater linking (late 60s, early 70s). Alan and Robin WA6CDR linked two existing UHF machines that both had control systems that were originally designed without linking in mind since no one has thought about it yet. The problem: how do you control one machine from the other? Alan came up with a hardware solution called a "prefix decoder". This was a PCB with a few (three I think) 88 mH toroids, a few caps, transistors and chips. The prefix decoder decoded just enough tones to decode exactly 3 touchtone digits. When the prefix decoder saw the magic 3 digit sequence it switched the control system from the usual UHF receiver to the link receiver for a while to allow the link to control the machine. Simple, efficient, easy to use. Second problem: How do you keep random touch tones originating from remote 2 meter base stations from accidentally controlling the system? The desire what only UHF "control operators" be able to function the remote system. Again this was 197x, what would you do? The simplicity and elegance of the solution still strikes me with awe: When the prefix is received the prefix decoder generated a telephone dial tone back down the link. This served two purposes: One the UHF "control operator" knew he has successfully obtained the remote systems attention and that it was awaiting his commands. And secondly (perhaps more importantly) any 2 meter users trying to muck with the system were immediately stopped in their tracks since the hilltops 2 meter transmitter was now keyed by the dial tone. I'm sure there were other ways to do it even in the 70s. I happen to think the prefix solution was an excellent one. 73's Skip WB6YMH
