You didn't say what the frequencies you are trying to measure are, Woulfy.
Some meters, especially the lower end ones (and unfortunately unless its a Bird, or HP- or above, that's going to be its category- but Hey, I've used those lesser-meters all the time
)- some of the lower end meters have real quirks in their circuitry. The suggestion to first try seeing what it does into a resistive dummy load is mine also. Comparing to a known standard, like a Bird meter into an antenna is my next suggestion.
Some esoterics to consider, especially if you are measuring UHF and other high frequencies-- does the meter cover those?.. I feel you probably have that in mind, but have you considered the length of the connecting coax to the meter ?
Certain wavelength fractions can do weird things, reading-wise. Don't over look the quality of your coax connectors-- an erratic connection is a real bugger too.
Okay, if all else fails, remember that SWR readings are often estimates at best. I just put up an antenna for a friend, on GMRS-- and she got a One point 2, point 5 -- we never look at it critically, but it was "low"--- "good enuff for government work."
Remember too, worse case---- you can always use your meter for relative measurements, if you know its limitations.
Lauri
