Try googling with "polyphase quadrature network"
I have used one of these as an RF network which worked acceptably well
to 30 MHz, though losses were significant.
I seem to recall the original article described one of these, though I
am not sure.

Richard


David J Windisch wrote:
Hi, all concerned:

In Ham Radio mag, Jan, 1978, there are some 90-deg phase-shift networks
covering 1-30 MHz.

Could an Elmer help me out with a lead to schematics, pls?

73, Dave, N3HE