Double Bazooka?
 

My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?

--
73's es gd dx de Ken KGØWX
Grid EM17ip, Flying Pigs #1055,
Digital On Six #350,
List Owner, Yahoo! E-groups:
VX-2R & FT-857

On Mon, 4 Apr 2005 16:02:04 -0500, "Ken Bessler"
wrote:
Is he right?

Hi Ken,

No.

This topic has enough coverage in the archive (use Bazooka as a
keyword) to fully explain his folly.

73's
Richard Clark, KB7QHC

A typical dipole is easily greater than 90% efficient. And a double
bazooka will be considerably less efficient than a dipole.

Ask your friend where he got those figures. I'd be interested in knowing.

Roy Lewallen, W7EL

Ken Bessler wrote:
My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?

On Mon, 4 Apr 2005 16:02:04 -0500, "Ken Bessler" wrote:

My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?
Hi Ken,
Those who tout the double bazooka have been misled for eons. That antenna is
simply a resistance-loaded dipole and the increase in BW is due to the
resistance loading of the dielectric in the coax that forms the dipole. The
shunt reactance of the shorted quarter-wave sections forming the dipole does
nothing to increase the BW. The principle is ok, and was used on military
equipment during WW2, but for the shunt reactance to provide the increase in BW
the feedline Zo needs to be at least two times the resistive component in the
dipole input impedance for the concept to work. Consquently, the double bazooka
as misused by the amateur community has been misengineered.

I published a long and detailed expose of this antenna in Ham Radio, August
1976, with a shortened version in QST, Sept 1976. I explain mathematically why
it doesn't work as many claim. It appears as Chapter 18 in Reflections 1 and 2,
and is available for downloading from my web page at www.w2du.com. Please review
this document before wasting your time and energy on a dud.

Walt, W2DU

Ken Bessler wrote:
My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?

The efficiency graphs in The ARRL Antenna Book indicate
that the double bazooka is NEVER more efficient than a
dipole and that it has lower efficiency at every frequency
other than resonance. Is your friend an Old Wife?
--
73, Cecil http://www.qsl.net/w5dxp

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In article fXh4e.129$Jt.53@okepread04, says...
My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?

I suspect your friend got his figures reversed.
Any properly-constructed half-wave dipole is well
over 90% efficient. The double bazooka gets its
meager bandwidth improvement by adding loss.

73,
Bob

--
+----------------------------------------------+
| Bob Schreibmaier K3PH | E-mail: |
| Kresgeville, PA 18333 | http://www.dxis.org |
+----------------------------------------------+

"Bob Schreibmaier" wrote in message
...
In article fXh4e.129$Jt.53@okepread04, says...
My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?

I suspect your friend got his figures reversed.
Any properly-constructed half-wave dipole is well
over 90% efficient. The double bazooka gets its
meager bandwidth improvement by adding loss.

73,
Bob

--
+----------------------------------------------+
| Bob Schreibmaier K3PH | E-mail: |
| Kresgeville, PA 18333 | http://www.dxis.org |
+----------------------------------------------+

Thanks Bob, Roy, Walter, Richard & Cecil!

Wow - all the guru's agree for once? That fact alone
leaves me to forget the idea of replacing my ladder
line/coax fed 40m dipole with a Bazooka.

Info - my current antenna started out as a Van Gordon
"All Bander", a 134' dipole fed with 100' of ladder line.
I trimmed 50' off the ladder line and have a 12' rg58
coax feeding a CD size 13 turn coax coil which feeds
the ladder line going up to the antenna (which I trimmed
to 7.185 mhz). It's a flat dipole (almost) up 25'.

Due to a lack of space, I would have had to take that
antenna down to put up the Bazooka so comparing the
two would have been almost impossible.

Thanks again, guys - you rock!
--
73's es gd dx de Ken KGØWX
Grid EM17ip, Flying Pigs #1055,
Digital On Six #350,
List Owner, Yahoo! E-groups:
VX-2R & FT-857

Who needs enemies when you have friends like that?

My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

===============================

Well, it sure makes a change from quoting or mis-quoting Terman.

The converse is true. The dipole would be more efficient.
Your friend is incorrect.


"Ken Bessler" wrote in message
news:fXh4e.129$Jt.53@okepread04...
My friend says that a double bazooka is 98% efficiant
and that a dipole is only about 70% efficiant.

Is he right? Will a double bazooka outperform a dipole
enough to notice a difference on 40m?

--
73's es gd dx de Ken KGØWX
Grid EM17ip, Flying Pigs #1055,
Digital On Six #350,
List Owner, Yahoo! E-groups:
VX-2R & FT-857