Topband: The "Magic-T" vs 0 degree and 180 degree hybrid combiner/splitters

[Richard (Rick) Karlquist]

Ham radio literature often IMHO misuses the term
"magic tee" to refer to a transformer-based
0 degree hybrid combiner/splitter.

AFAIK, a magic tee is a WAVEGUIDE device as explained here:

https://www.tutorialspoint.com/microwave_engineering/microwave_engineering_eh_plane_tee.htm

and here:

https://blog.pasternack.com/uncategorized/magic-tee-magical/?gclid=Cj0KCQiApY6BBhCsARIsAOI_GjZHPm6HGT9O06rgnjXBXyc_xUD1aezOCcrNMuSrA4yrSjWqE-r3uFcaAotvEALw_wcB

In some loose sense, what hams talk about as a magic tee
is a lumped element equivalent of the waveguide magic tee.
Outside of ham radio, it is referred to simply as a 0 degree
hybrid.

The 0 degree hybrid circuit has a dual version called a 180 degree 
hybrid combiner/splitter that seems to be less well-known in ham
circles.  It is also a sort of lumped element equivalent
of the magic tee, as explained here:

https://electronics.stackexchange.com/questions/483616/what-does-the-25-%CE%A9-termination-resistor-do-in-a-0-180-degree-hybrid-power-splitt

The 180 degree hybrid has several advantages over the 0 degree hybrid:

1.  The input vs output impedance level is a function of
the turns ratio and therefore is not confined to a value
of 1:2.

2.  It happens to provide so-called "Galvanic Isolation" which
is sometimes helpful

3.  It inherently provides a 180 degree phase shift.

I often see 8 circle phasing networks that use a 3 piece
ensemble of separate magnetic parts, consisting of:

1.  A 1:1 transformer wired for a 180 degree phase shift
2.  A 0 degree hybrid ("magic-tee"), and
3.  A 37.5 ohm to 75 ohm transformer.

A single 180 degree hybrid replaces all 3 of the above.
(There is nothing "incorrect" about the 3 piece ensemble;
it's just needlessly complicated).

My 9 circle array uses this very successfully.

73
Rick N6RK