[TowerTalk] Log Periodic Feed

[James Wolf]

>>>Think of the dual boom as an open wire transmission line having a
characteristic impedance of something like 300 ohms, and a spacing of
several inches.
The feedline should drop down vertically from its attachment point to the
two booms and then turn and run parallel to the two booms, but below them by
6 to 12 inches, so there is minimal disruption to the open wire line.  IMHO,
taping it to either boom makes no engineering sense at all.  It does make
marketing sense, in that the antenna might sell better if they show a nice
"clean" installation vs the feedline hanging down.

Some TV antennas are designed this way, and you never see the coax taped to
the booms.  It just hangs down.

Rick N6RK
_______________________

This is my current approach.  Unfortunately, there is not enough clearance
to run the coax through the boom to the back of the antenna due to the way
the elements connect to the boom.   However, what if I were to electrically
connect a piece of aluminum tubing to the bottom boom and run the coax
through it to the read of the antenna where the shorting stub is and then
drop down and bring it back to the boom.  That would likely require no choke
at all since it is the "cold" point of the antenna?

Jim - KR9U