[TowerTalk] Hygain Baluns or Coaxial Coil

[Bill Coleman]

On Feb 27, 2007, at 8:26 AM, Stan Stockton wrote:

> Wind about 6 turns of coax tightly on a 4" UV resistant PVC pipe  
> which will be good for 20/15/10.

Electrically, this is a very effective balun. I had planned to do  
this when installing my A3S. In fact, I even figured out a method to  
mount the 4" PVC to the boom by cutting at 45 degrees and then using  
a U-bolt to hang the balun underneath.

In the end, I opted for a different solution. I had purchased some  
ferrite beads with a 5/8" I.D. and about 1.25" long at a hamfest at a  
bargain price. I measured one of these with an MFJ-259. A simple  
calculation showed that about 15" of these beads would give adequate  
balancing impedance from 7-28 MHz.

These beads are slid on the coax before connecting to the antenna. I  
used 14 gauge THHN solid wire to wire tie the coax below the boom.  
Makes a tidy and effective balun.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901