[TowerTalk] Bazooka antenna

[Jim Brown]

On 11/7/2011 10:49 PM, Mike wrote:
> I use full-size Double Bazookas on 160m and 80m, they actually are not bad
> on bandwidth. The 160m certainly has greater bandwidth than the Carolina
> Windom that I had up and is quieter.

ANY off-center fed antenna (like the Windom) will be inherently noisy 
because it is badly unbalanced, which makes the feedline part of the 
antenna.  THAT'S why your Bazooka seemed quieter by comparison.  That's 
also why chokes are well known to fail on Windoms -- the extreme 
unbalanced places a lot of common mode voltage across it, so you need a 
VERY high choking impedance to kill the common mode current. If the 
choke is too small to do that, it fries.  For 100W, I'd say at least 
5,000 ohms.  For 1.5kW, 15K ohms may not be enough. 5,000 ohms for 80 
and 160 is 14 turns through a #31 toroid, or at least 9 turns through 
five #31 toroids.

For today's world ,where there's a lot of RF noise around us, the Windom 
in all of its variations is a lousy antenna.

73, Jim Brown K9YC