Topband: 160 Meter BALUNS

Bill Tippett btippett at alum.mit.edu
Tue Dec 23 20:50:20 EST 2003


	Here's a simple balun that works well on 80/160
which requires only 100 inches of RG-8X coax.  I used it
for many years in Colorado running 1.5 kW to a trapped
dipole for 80/160 with no problems.  The original design
came from a Ham Radio series but I don't have the
exact reference.  I recall the designer had made
measurements using an HP Network Analyzer and
the balance performance was excellent on 80/160
compared to commercial baluns.

1.  Carefully remove a small ring of the coax cover at
~100" from the end.

2.  Solder ~100" of wire around the braid at this point.
I recall I used #16 insulated wire.

3.  Loosely wind 7 turns of the coax in one direction
(about a 6 or 7" diameter coil) and loosely wind 7
turns of the wire in the OPPOSITE direction.

4.  Solder the wire to the inner conductor at the end
of the coax (after separating 2-3" of braid as a pigtail).

5.  Waterproof the coax ends and the area where the
wire was attached.

6.  Secure the loosely bundled coil of coax and wire
with tape or tie-wraps.

7.  Attach the coax shield to one side of the antenna
and the center conductor (including attached wire)
to the other side.

	Instead of using 50' of coax, this uses only
a bit over 8' and works well.  Maybe someone has
the exact Ham Radio reference but I'm fairly certain
my memory of the construction is correct.  If I made
a mistake, hopefully someone will correct it.

			73 & Merry Christmas!

			Bill  W4ZV



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