Re: *muppet alert* How do I use my multimeter?

[matthew@xxxxxxx]

Ian

Thanks for your help. I set the meter to 200 ohms and the results are:

1) 1

2) Anything from 0.7 to 170!!!

The meter is a digital one and for test 2 i would have expected a
constant readout? I'm not waving the cable around and the prongs are
firmly pressed down.

Any comments?

matt
--- In ukha_d@y..., "Ian Lowe" <ian@w...> wrote:
> two quick tests matt:
>
> make sure both ends are "clean" (ie not shorting together
core and
screen)
>
> Measure resistance between core and screen: if you get a dead short
> (anything up to about 15-20 ohms) then your cable has stretched
internally
> and the core and screen are touching.
>
> then take one end and twist it together so the core and screen are
shorting:
> go to the oter end and emasure: anthing *Except* a dead short means
your
> cable has been damaged and one of the conductor paths is broken.
>
> Ian.
>
> ----- Original Message -----
> From: <matthew@m...>
> To: <ukha_d@y...>
> Sent: Saturday, June 16, 2001 10:36 AM
> Subject: [ukha_d] *muppet alert* How do I use my multimeter?
>
>
> > Having put in quite a long run of coax from node zero (garage) to
the
> > loft as the downlink from the aerial, I noticed that about
12"
>from
> > the ceiling of the garage it has gone a bit floppy.
> >
> > Suspecting the coax may have broken inside (bugger!) I've gone
out
> > and bought a cheapo multimeter.
> >
> > I've stripped the end in the loft, and twisted the braided screen
> > around the solid core. Back in the garage, the options on my
meter
> > are 2000k, 200k, 20k, 2000 or 200 ohms. I guess the plan is to
set
> > the meter to one of those, touch one prong on the core and one on
the
> > screen and look at the value displayed.
> >
> > Trouble is I have no idea what I'm looking for. I don't know what
> > values will tell me the cable is broken and what values will tell
me
> > im ok. I also have no idea what OHMs to set the meter to.
Assuming
> > the cable isn't broken, is there some way I can test the strength
of
> > signal ie. how much loss there is over the run? I'm reckoning on
four
> > runs of coax from the loft to the garage and it's CT100 cable but
if
> > the losses are too great I'll have to get some CT125.
> >
> > Any help and advice gratefully listened to!
> >
> > Yours muppetationally
> >
> > matt
> >
> > (ps. I promise one day I will contribute something worthwhile to
this
> > group rather than just ask questions all the time!!!)
> >
> >
> >
> >
> > ____________________________________
> > Automated Home UK
> > http://www.automatedhome.co.uk
> > ____________________________________
> >
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> >
> >




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