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Re: Time Domain Reflectometer (was Re: internet outages)




On Mon, 24 Dec 2018 08:09:11 -0500
Gene Heskett <gheskett@xxxxxxxxxxx> wrote:

> On Monday 24 December 2018 04:26:05 Joe wrote:
> 

> >
> > There is normally a real Nyquist bandwidth quoted somewhere in the
> > small print. I used to repair and calibrate Hitachi scopes for a
> > while, until everyone stopped using them.  
> 
> I wonder why, Joe. My V-1065 still works well enough to measure
> frequency at a 1% accuracy, and its now pushing 35yo. In a pinch I've
> looked at the output sample of an old analogue tv transmitter to
> adjust the modulation depth when the monitor was bonkers, it was
> actually usable at 180 mhz. 

I used to see about three or four of the 665/1065 series a week, mostly
ten years old with mains switcher problems. Mostly routine fixing, after
the initial pain of troubleshooting a mains switcher. Capacitors,
mostly. Even the high-ripple ones will only run so long before they dry
up.

Then over about six months, it dropped off to nothing, and we never
saw any more. I assume oscilloscope use had dropped off enough that
people could just put a dead one in a cupboard wand say 'we'll get it
fixed if we ever need it'. Fortunately, oscilloscopes were a minor
sideline, so I didn't run out of work. The company still has a 1085,
which I use occasionally. At home, I have a 35-yo Kikusui, and a
temperamental Tek 465B of uncertain age, but older than that.

-- 
Joe