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

["Ian Lowe" <ian@xxxxxxx>]

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@xxxxxxx>
To: <ukha_d@xxxxxxx>
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!!!)
>
>
>
>
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