RadioBanter - View Single Post

January 3rd 05, 11:06 PM

On 3 Jan 2005 13:09:32 -0800, wrote:

I tried with an ohm meter but all it would display is "1" on everything
or nothing at all.

Hi OM,

For all intents and practical purposes, your Ohmmeter is barely a
continuity tester and wholly useless in forecasting RF resistance if
the material is unknown.

There are very few retail Ohmmeters that are very accurate below 10
Ohms and clearly inadequate below 1 Ohm. The proper instrument would
use what are called "Kelvin clips," which are simply the leads to a
Kelvin Bridge. This is a four terminal measurement and it makes heavy
demands on a current source and requires a good shunt to insure decent
resolution and accuracy.

Unless you are building a small loop and need to confirm contact and
joint resistance, you will probably never need one. Wire tables
provide enough information that is accurate.

73's
Richard Clark, KB7QHC