Cecil Moore wrote:
Keith Dysart wrote:
I thought that when you specified 5 and 10 degrees in your
problem statement, you meant electrical degrees. That is, the
phase shift encountered by the forward travelling wave.

That specification is the same for physical and electrical
degrees because we are dealing with a single Z0 piece of
transmission line. The 100 ohm line is indeed 10 degrees
long both physically and electrically.

Certainly, the answer was in terms of electrical degrees. That is,
the phase shift encountered by the forward travelling wave.

You, and others, are going to be surprised to find out the
600 ohm section is only 43 degrees of physical length. How
can 43 degrees of 600 ohm line add to 10 degrees of 100 ohm
line to equal 90 electrical degrees of stub? Hint: Like I
told Roy and Tom years ago, there's a 37 degree phase shift
at the impedance discontinuity between the 600 ohm line and
the 100 ohm line. 43+37+10 = 90 electrical degrees.

Understand that simple stub example and you will understand
loaded mobile antennas. Most of the "experts" here are just
full of you-know-what.

Actually, you got it wrong, Cecil. It's -43 degrees, which means
if you wanted to make one it would be about 317 degrees. (Actually,
I got -46.613 degrees.) Maybe you can make a length using negative
degrees, but it's tough for me to do.
73,
Tom Donaly, KA6RUH