Re: internet outages

[Doug <dmcgarrett@optonline.net>]

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/copper-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