RadioBanter - View Single Post - Power Dividers / Co-Phasing Harness question

Jim - NN7K · March 10th 07, 12:53 AM posted to rec.radio.amateur.antenna

See comments below.

wrote:
Hi all,

When co-phasing two identical two meter yagis, is it necessary to use
the "power dividers" sold by the antenna manufacter? NO!, use ODD
multiples of a 1/4 wavelength (dont forget the
velocity factor) of 75 ohm coax (for 50 ohm ants)!

If two odd
multiples of 1/4 wavelength 75 Ohm coax is carefully constructed and
run into a T connector, won't this achieve the same thing? Is there a
real peformance difference? Only in the small difference of loss in the
coax vs. the loss in the (devider+ coax lengths)
to the antennas! And ALSO, consider that the
lengths from a power devider must be identical
(to the antennas, and fed in PHASE), tho they are
NOT limited to the
(Odd 1/4 wavelengths, of a impedence matching
setup! Also, If you use , say 1/4 and a 3/4 wave
pieces for the 75 ohm example, (it works), BUT
remember the feed on antenna left right, and
the other antanna Right to LEFT! (180 degree
phase shift)! JIM NN7K

Thanks,
Scott, WU2X