I suspect the "regenerative" came from the WWII TT63 "regenerative repeater"
that was modified to use as a TU in the old days. As I recall it took in a
"digital" signal and retimed it and then re-keyed the line with a polar
relay. If you put a pair of filters and couple of diodes in front of it you
were on the air.
Keith Regli (K7KAR)
mailto:keith@kregli.com
http://www.kregli.com
-----Original Message-----
From: rtty-bounces@contesting.com [mailto:rtty-bounces@contesting.com] On
Behalf Of Kok Chen
Sent: Tuesday, November 09, 2004 4:52 PM
To: RTTY Reflector
Subject: Re: [RTTY] HAL ST-8000
On Nov 9, 2004, at 1:09 PM, jduerbusch@charter.net wrote:
> There is a nice artice on putting the ST-8000 ahead of the PK-232 on
> my website:
> http://www.qsl.net/k0bx
It is much easier to do than described in that article, really.
All you need to do is supply audio from the rig to the ST-8000 as if you are
using the ST-8000 for real. You then connect the AFSK output (yes, AFSK
output) of the ST-8000 to the Audio input of the TNC (I'd used my ancient
KAM Plus as the TNC). Not counting the AC power cord, those are the only
two connections you have to make to the ST-8000. No RS-232, no nothing
else.
The only difference from the standpoint of the TNC is that the audio comes
to it from the ST-8000 rather than from the rig.
The rest of your station remains as is, the same computer program and all.
Think of it like wiring in an audio pre-amp to the audio line between the
rig and the TNC.
It is obscurely documented in the ST-8000 manual (I don't have the ST-8000
manual in front of me, else I could point to the paragraph) as
"Regeneration" I believe. Many textbooks (and the Watkins-Johnson white
paper you can find by Googling) and the Timewave 599zx calls this process
"Remodulation."
What regeneration does inside the ST-8000 is that it demoduate the incoming
audio as usual, but the resultant Baudot keying waveform is fed back to the
built in AFSK generator of the ST-8000.
In this mode, the ST-8000 puts out an absolutely clean and strong AFSK RTTY
signal; no noise, no QSB even if the input from the rig is full of QSB and
QRM.
The only errors you print will not be from the TNC, but from the ST-8000
remodulating with the wrong bits to start with. So you see the bits
precisely as the ST-8000 see them, but the TNC is the one that does the
conversion of the tones to Baudot and then to ASCII for your computer.
There are a couple of jumpers, or DIP switches (I don't recall which
now) that you have to change inside the ST-8000 if memory serves; it is all
documented in the manual. It took me a while to find it in HAL's manual,
since I was looking for the term "remodulation," but eventually found it by
reading every sentence of the manual, page by page :-).
But I knew it had to be there; it would have been too dumb not to include
the function, and HAL guys are far from dumb. So don't be like me, but go
look for the word "regeneration" (I think that is what HAL called it)
instead.
I know a couple of the HAL guys read this reflector. They can probably
help.
73
Chen, W7AY
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