Ron, somewhere in the bottom of my junque box, I still have a few relays and
88mh toroids. It was nice when the #15 was working but it was like the last
abcessed tooth I had pulled--fine when it worked but a GREAT relief to get
rid of it!
73, Frank, K4VMO
----- Original Message -----
From: "Ron Notarius WN3VAW" <email@example.com>
Sent: Friday, April 04, 2003 5:32 PM
Subject: Re: [TenTec] Old Modes never die... they just get soundcard
> Gerry, I agree with you 1000% -- but I still occasionally miss the sounds
> smell of that Model 15 in the shack. Even though maintaining it & the
> tube-type TU (remember when we used to call THOSE modems as opposed to
> we hook to the computer these days -- well, some of us still hook to the
> computer at least) was a royal PITA and you had to be a mechanic sometimes
> to keep the old TTY units running.
> But still...
> Software can't replace everything.
> 73, ron wn3vaw
> "There must be some mistake. The Pirates in first? QRM on my end,
> --John W3ULS (and there's no QRM, either)
> ----- Original Message -----
> From: "Dr. Gerald N. Johnson, electrical engineer" <firstname.lastname@example.org>
> To: <email@example.com>; <firstname.lastname@example.org>
> Sent: Friday, April 04, 2003 4:01 PM
> Subject: Re: [TenTec] Old Modes never die... they just get soundcard
> RTTY accomplished in the old fashioned ways with TTY machine or computer
> in terminal mode and a dedicated TU (terminal unit) are simplistic
> compared to the wheedles and whistles of the many alternative modes.
> Much of the hardware (and software) for the alternative modes neglects
> some of the things we learned making RTTY work such as the low pass
> filter after the discriminator and the slicer after that which made a
> good TU (as the ST-6 and derivatives) perform superbly, copying signals
> that weren't audible. Some of that has rubbed off on PSK-31, I'm not
> sure about the other modes.
> 30 or 40 years ago, the few hams on RTTY were highly technical for the
> most part. Very few BOUGHT TU or complete RTTY machine, most assembled
> from parts (no kits) and many used our own custom circuits. Ham
> operators of RTTY machines were machine assemblers and adjusters first
> and talkers second which made for a quite interesting group.
> I'll grant these days (and I sold my best model 15 while there was a
> market and I didn't have to pay to have it hauled off) that the clanking
> of the printer and its pickiness about adjustments isn't missed when I
> compare running an Epson dot matrix printer on commercial weather wire
> service for 6 or 8 years with nothing more than ribbons and paper, while
> the best of the TTY printers required annual service and lubrication,
> plus ribbons and paper.
> But RTTY has a modicum of simplicity compared to the multitone whatsits
> of the modern digital modes. And works a whole heap better than 300 baud
> packet simply because the bit length is long enough that the receiving
> detector can average propagation changes over most of the bit. And with
> its relative simplicity all (or nearly all) users can understand its
> techniques. The diversity of the sound card based digital modes can make
> it difficult to KNOW what one is using and how it works, other than it
> works or it doesn't work.
> I'll claim that a good TU (such as the ST-6 using toroids for input
> bandpass filter and discriminator) can copy RTTY solid through QRM that
> the sound card wouldn't not even notice there was RTTY signal on the
> frequency simply because that toroid based TU has better dynamic range
> than the sound card and better INPUT selectivity.
> 73, Jerry, K0CQ
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
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