Re: internet outages
On Sunday 23 December 2018 19:33:38 Doug wrote:
> On 12/23/2018 04:24 PM, David Christensen wrote:
> > On 12/23/18 12:11 PM, rhkramer@gmail.com wrote:
> >> On Sunday, December 23, 2018 02:50:34 PM David Christensen wrote:
> >>> On 12/23/18 2:02 AM, Curt wrote:
> >>>> On 2018-12-22, David Christensen <dpchrist@holgerdanske.com>
wrote:
> >>>>> 1. Test and verify your network cables:
> >>>>>
> >>>>> https://www.idealnetworks.net/us/en/products/cable-testing/coppe
> >>>>>r-testin
> >>>>>
> >>>>> g/cable-verifiers-linkmaster.aspx
> >>>>
> >>>> I think in my particular home situation I'd rather just replace
> >>>> my 10 dollar ethernet cable with a new one (or swap in a new one
> >>>> to see if it
> >>>> makes some appreciable difference) than purchase an $80 device to
> >>>> test whether it's failing or not (in which former case I'd then
> >>>> be out $90, which is a real nice load of money).
> >>>
> >>> If you own a continuity tester or multimeter, you could build a
> >>> pair of RJ-45 jacks with pigtails for a few dollars and use those
> >>> to test your cables.
> >>
> >> Wow, for $80 I would have expected something that would measure dB
> >> loss and
> >> maybe even a time domain reflectometer (well, maybe not that).
> >
> > Please provide a URL for such test instrument(s).
> >
> >
> > One other point -- MRSP is not the same a street price:
> >
> > https://www.homedepot.com/p/Ideal-LinkMaster-UTP-STP-Wiremapper-and-
> >Tester-62-200/100091453
> >
> >> I have seen those continuity type testers on ebay for under $10
> >> (the test sets
> >> with two devices, both with RJ-45 jacks, you plug the ends of the
> >> cable into
> >> those (one at each end of the cable), and then the "master device"
> >> tells you
> >> whether the pairs are connected properly and there is continuity).
> >
> > I am sure there are cheap clones and/or counterfeits of the
> > LinkMaster available. I prefer genuine, reputable brands.
> >
> >
> > David
>
> RE: Time Domain Reflectometer:
>
> Theoretically, you can build your own with a fast pulse generator and
> an oscilloscope. The trick is, you need a REALLY FAST oscilloscope!
> The pulse generator is easy, just a couple of transistors, maybe a
> diode. The circuit is probably in every edition of the Radio
> Amateur's Handbook. The scope is expensive. If you don't have at least
> a 1GHz digital sampling scope, don't bother!
>
> --doug, WA2SAY, retired RF engineer
Doug, another retired tv CE here. And I won't make the statement that its
not worth the bother. In a pinch I've made one from a radio shack ttl
pulse generator and a 100 mhz scope, and was close enough that when I
sent a tower crew up to dis the transmission line & find a burnout, they
found the first fried teflon disk, and a bad bullet cobbled up
with "whisky cups" at the first joint they opened up. Plenty close
enough for the girls I go with. Part of the secret is of course the
teflon disked 3.125" line has a prop speed just above 98% of C, while
the sterate versions are only about 97.25. You see EVERTTHING with that,
even bullet dents from some kid with a Christmas 22. Still, I wasn't
able to count the 20' joints with that slow ttl signal and scope. That
takes the real thing, and even then you might have to wait till the
middle of the night to get rid of the local daytime AMers that can sure
screw up your display. The tek version uses a tunnel diode, which has a
femtosecond switch time, but is only about a half volt switch.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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