Cecil Moore wrote:
Tom Donaly wrote:
O.K., Cecil, I finally figured out what you want to do. You want
a zero ohm input impedance, just like a 1/4 wave open stub. In that
case, you're absolutely right, the 600 ohm line should be 43.387
degrees long. If you call the 100 ohm line, line 1, and the 600
ohm line, line 2, then the criterion for what you want is:
tan(Bl1)*tan(Bl2)= Z01/Z02. This behaves sort of like a backwards,
transmission-line, Helmholtz resonator. I still don't know where you
come up with the 90 degree stuff.

For an open stub to exhibit a zero ohm input impedance,
it must be electrically 90 degrees long (or 270 ...).
That's where the 90 degrees comes from. The example
stub is electrically 90 degrees long while being 53
degrees long physically.

(The rest deleted.)
O.k., Cecil, you said it, now prove it. There's no requirement
for a 90 degree phase shift when you do the math. Don't expect me
to do it for you this time. Since I did some math for you, you can
do some for me: Given the above formula, if you know l1, l2, and
Z01, and Z02, what's the formula for B? It should be easy, right?
73,
Tom Donaly, KA6RUH