[time-nuts] WWVB phase modulation test April 15-16

Azelio Boriani azelio.boriani at screen.it
Thu Apr 12 09:15:01 UTC 2012


I have a couple of BNC-to-scope_probe adapters...

On Thu, Apr 12, 2012 at 9:56 AM, Hal Murray <hmurray at megapathdsl.net> wrote:

>
> > Just the T and a DC block. 1/4 wave at 60 kHz is far, far longer than any
> > cable you have.
>
> This is time-nuts.  Somebody is likely to do something most of us would
> consider, well, nutty.
>
> It's probably reasonable to make a lumped-circuit approximation of a long
> transmission line at 60 KHz or 100 KHz.
>
> Many years ago, when we were working on early 10 Mb Ethernet, a friend
> rigged
> up a good approximation to a long chunk of coax with 1 R and 1 C and a few
> clip leads.  It looked pretty good on a scope.
>
> I ordered several 500 ft spools of coax so we could test the real thing.
>  500
> ft of Ethernet coax (not thinwire) is a serious spool.  A key step was
> getting the maintainance guy to build a dolly with serious casters.  He was
> happy to do something strange.  The result was slight overkill which is
> what
> I wanted.  It worked great.  Every lab should have one.  :)
>
> How many of you have used the Tek scope-probe to BNC adapter?  I tried a
> bit
> but couldn't find anything on the web.  The idea was (roughly) that you
> put a
> BNC Tee in the line you wanted to watch and this magic gizmo on the Tee.
>  One
> end was BNC.  The other end was a hole where you inserted a scope probe.
>  The
> idea was to avoid the inductance on the pigtail for the ground cliplead.
>
> ----------
>
> Not quite so many years ago, we built a SONET/OC-3 delay box.  It was just
> a
> fiber optic receiver, FPGA, knobs, memory, and fiber optic transmitter.
>  The
> FPGA could just barely  run at 155 megabits.  We used a recycled memory
> module.  I think it was 36 bits wide with 1 megabit chips.  The idea was to
> let the software guys test long links in their lab.  It worked great.  (I
> think that size memory covered (roughly) California to Paris.)
>
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



More information about the Time-nuts_lists.febo.com mailing list