"Richard Clark" wrote in message
...
On Mon, 10 May 2004 18:13:00 GMT, Richard Clark
wrote:
Sagging between two plates would seem to me to be a non-issue.

On further reflection (no pun), I would retract this because line sag
would necessarily induce a voltage variation between the probe and the
line that did not actually exist (probe tracking is very important, of
course). Sag may not introduce residual SWR, but it may appear to.

Also, yes, you could use a less than one wavelength long slotted line
- provided you had a sliding load to make up for the remaining length.
In other words, instead of moving the probe to measure the
crests/troughs, you move the load (or both very carefully). When you
introduce limitations into design and wish to maintain precision, it
necessarily follows that you need more standards to compare against.

73's
Richard Clark, KB7QHC

Richard

This is a good example of how out of touch I am. I thought I could get
all the impedance measuring data from a line only slightly over 1/4 wave
long. Even after thinking about it for several minutes, I cant convince
myself that the slotted line has to be more than 1/2 wave long.

Jerry