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

["Keith Doxey" <ukha@xxxxxxx>]

1. Test For Short Circuit
Set the meter to 2000k (2megohm) and test on one end across centre and
screen making sure that the other end is not shorted out (wires touching).
The result should be infinity. Most digital meters show this as
"1" at the
left hand side of the display indicating "Over Range". On an
analogue meter
the needle shouldnt move from rest. Anything other than thisa indicated
partial or total short circuit.

2. Test for Open Circuit
Set the meter to 200ohm Range. Join the centre to the screen at one end and
then test at the other for a short circuit. Ideally the reading should be
"000.0" or the needle wrapped round the end stop. In practice it
may be a
few ohms but should be less than 10. If the reading is higher than that or
even infinity then the cable is damaged.

HTH

Keith


> -----Original Message-----
> From: matthew@xxxxxxx [mailto:matthew@xxxxxxx]
> Sent: 16 June 2001 10:37
> To: ukha_d@xxxxxxx
> 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
> ____________________________________
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>




____________________________________
Automated Home UK
http://www.automatedhome.co.uk
____________________________________

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/