[TowerTalk] How to create discrete phase shift in stack?

[Richard (Rick) Karlquist (N6RK)]

> 1) What's the most practical way to accomplish a phase shift of 
> other than 180 degrees? If I use coaxial delay segments, they 
> would need to be relay-switched at both ends, not just one end as 
> for the 1/2-wavelength case. Right? Is there a better way to do it?
> Bill / W5WVO

You can create a lumped element delay line consisting of a pi
network with electrical phase shift of +X degrees if you use shunt
capacitors having a reactance of Zo*Cotangent(X/2) and a series
inductor have a reactance of Z*(Sine X).  You can also use an 
equivalent tee network with series capacitors with reactance of
Zo*Tangent(X/2) and a shunt inductor of reactance Zo/(Sine X).
This network will have an electrical phase shift of -X degrees.
That may be more compact than a coiled up roll of coax.  Since
I hate mounting connectors on coax, this is most practical way
to get a delay, especially if you want to be able to experiment with
it, IMHO.

For further reading, see Fig. 8 on
page 6 of http://www.n6rk.com/driving_the_7_hex.pdf.

Rick N6RK