[GreenKeys] More where that one came from

[Bill Henry]

Herb - and all,

The AMH times were dictated by USAF spec. to match those used in the 
Frederick 1280A/M modem.  It has been a long time since I designed 
the ST-8000A (1990) - but - circuit pot R56 (on the lower modem 
board) is the calibration adjustment for AMH delay.  Mark the factory 
setting of R56 before changing it if you want to be able to get back 
to where you started.  Fixed resistor R8 (68.1K) sets the delay for 
the smallest increment to 1.0 second (SW2-8=ON).  Setting all 
sections of SW2 to ON should reduce the time to 1/2 second or maybe 
less.  Also, paralleling resistor R9 (274K) with a lower value will 
reduce the time for all settings of SW2 (try maybe 24K).

Good luck, and have fun.

Bill Henry

At 02:45 PM 6/3/2009 -0500, Herb Graeber wrote:
>Thanks Jeffrey.  I've got two of those rascals.  One is
>NIB and the other was used.  I modified the used one
>like Jack (K0TTY) did except that I installed a Rat
>Shack 8 conductor phono jack on standoffs over the
>ventilation holes in the back left top corner.and ran the
>cables through the hole where the diversity female was.
>
>I bought DSRTTY and am happy with the ST-8000A with
>the exception of the Automatic Mark Hold (AMH) and the
>time delay for it to change to the Mark-hold state.  The AMH
>setting is internal and if the audio level changes any than the
>ST-8000A starts printing garbage.  AND, why only a minium
>of 1 second delay?  Thats 4 or 5 garbage characters when-
>ever you get a LOS.  Sure would like to see a level control
>and a threshold control on the front panel.  Oh well...
>
>73...Herb K5HG
>
>
>----- Original Message -----
>From: "Jeffrey Angus" <jangus at socal.rr.com>
>To: "Herb Graeber" <hhg at suddenlink.net>; <larryradio at att.net>; "Greenkeys"
><greenkeys at mailman.qth.net>
>Sent: Wednesday, June 03, 2009 2:25 PM
>Subject: Re: [GreenKeys] More where that one came from
>
>
> >
> >> Are these new or "refurbished"?  Did it come with
> >> the manual and the amphenol male connectors?
> >> I got one sealed, new in the box, like the government
> >> bought it with all the accessories and manual but I
> >> paid more than $79.00.  :>(
> >
> > I can't speak for the others on sale now, but the one I bought
> > came reboxed and looked like it was just pulled out of service.
> > IEEE power cord, and the data and audio connetors with
> > the cables cut off at about 12"
> >
> > All things considered, with what they cost new, it was an
> > exceptionally good deal.
> >
> > Jeff-1.0
> > wa6fwi
> >
> >
>
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