Using a 259 is a big help for antenna builders, but before
using it one should know that the power supply does not
always break down the oxides formed at the circuit
connections, thus showing inconclusive results.
It takes at least 20 volts to breakdown the
oxides every time with confidence ( and that includes silver).
So the use of a wallplug transformer with a 20 volt secondary
to create a spark across the coax connectiori will always
breakdown the oxides prior to using the 259.
Actually, it is always good form to always break down oxides
before using hand held measuring techniques which usually are
battery driven. This is the reason that reed switches are the
contacts of choice when using 12v computor driven circuitry,
since with gold plated contacts the underlying surface
often leaches thru the gold plating.
Have a happy day
Art Unwin KB9MZ....XG (uk)