Our vacation house has about 75 of plastic rain gutters on 3 sides of
the flat roof at about 20 feet up (2 story). I was thinking about
laying a 40m dipole in there with no connection to anything on the
house. The only question I have is, is that there is a 2" strip of
metal flashing about 8 inches above the gutter, for the length of it.
How bad do you think this would screw up a dipole that's essentially
parallel to it?
This station would be for emergency use primarily to talk with a
station about 85 miles away with mountains in between so it doesn't
need screaming dx performance... ground waves and cloud warming is all
that's necessary...

Joey

Joey wrote:
Our vacation house has about 75 of plastic rain gutters on 3 sides of
the flat roof at about 20 feet up (2 story). I was thinking about
laying a 40m dipole in there with no connection to anything on the
house. The only question I have is, is that there is a 2" strip of
metal flashing about 8 inches above the gutter, for the length of it.
How bad do you think this would screw up a dipole that's essentially
parallel to it?

It will act somewhat like guy wires which can cause
distortion in the radiation pattern and losses.
With any luck, it will have a high impedance and
not have much effect. Try it and see what happens.
Worst case, you may need to cut a slit every 1/4 WL
to keep the currents low.
--
73, Cecil http://www.w5dxp.com

On Sat, 08 Sep 2007 12:53:38 GMT, Cecil Moore
wrote:

Joey wrote:
Our vacation house has about 75 of plastic rain gutters on 3 sides of
the flat roof at about 20 feet up (2 story). I was thinking about
laying a 40m dipole in there with no connection to anything on the
house. The only question I have is, is that there is a 2" strip of
metal flashing about 8 inches above the gutter, for the length of it.
How bad do you think this would screw up a dipole that's essentially
parallel to it?

It will act somewhat like guy wires which can cause
distortion in the radiation pattern and losses.
With any luck, it will have a high impedance and
not have much effect. Try it and see what happens.
Worst case, you may need to cut a slit every 1/4 WL
to keep the currents low.

Thanks, I may just whip up a dipole and do that! Was also looking at
a RadioWavz Bazooka on 40m as well... dunno how that would compare
since it radiates differently... only one way to find out!

Joey joey29034atyawwhodotcom wrote in
:

Thanks, I may just whip up a dipole and do that! Was also looking at
a RadioWavz Bazooka on 40m as well... dunno how that would compare
since it radiates differently... only one way to find out!


Wow, a miracle antenna. Their claims include:

Advantages:
* Broad bandwidth
* Almost unaffected by environment
* Positive gain with reference to a common dipole operating under the
same relative conditions up to 3.6 db
* Greatly attenuates harmonics(almost eliminates interference!!!
* Substantial decrease in static charge build-up
* Non-directional. (as a inverted V)
* Great for DX!!!

Can you believe that?

But wait, you wanted mo http://www.radiowavz.com/html/bazookas.htm .

My study of a typical Double Bazooka antenna system at
http://www.vk1od.net/DoubleBazooka/index.htm indicates that although it
might have slightly greater VSWR bandwidth (FWIW), it has more loss than
a conventional dipole.

Though it is likely to be poorer, I doubt you would notice it... but why
go to the trouble and expense for something that is likely to be poorer?

Owen

On Sep 8, 7:09 pm, Owen Duffy wrote:


My study of a typical Double Bazooka antenna system athttp://www.vk1od.net/DoubleBazooka/index.htmindicates that although it
might have slightly greater VSWR bandwidth (FWIW), it has more loss than
a conventional dipole.

I believe Walter Maxwell also wrote an article about that a few years
back.
There is no free lunch with the double bazookas. I don't use them
myself.
Not so much because of the slight extra loss, more that coax weighs
too much to use as antenna wire unless you have really strong
supports.
Regular wire is also a good bit cheaper. :/
MK

On Sep 8, 7:09 pm, Owen Duffy wrote:


My study of a typical Double Bazooka antenna system athttp://www.vk1od.net/DoubleBazooka/index.htmindicates that although it
might have slightly greater VSWR bandwidth (FWIW), it has more loss than
a conventional dipole.



I believe Walter Maxwell also wrote an article about that a few years
back.
There is no free lunch with the double bazookas. I don't use them
myself.
Not so much because of the slight extra loss, more that coax weighs
too much to use as antenna wire unless you have really strong
supports.
Regular wire is also a good bit cheaper. :/
MK

wrote in
ps.com:

On Sep 8, 7:09 pm, Owen Duffy wrote:
I believe Walter Maxwell also wrote an article about that a few years
back.

Walt did indeed write on the Double Bazooka. Ch 18 of Reflections II is
dedicated to the topic.

If I understand his discussion properly, Walt treats the coax stubs as pure
reactances, ie lossless. My analysis treats them as lossy transmission
lines, and the outcome will be different for that reason.

Further, my analysis treats the system as a system, and so captures the
effects of feed line loss, so it is more complete.

My article also models the cross-connected Double Bazooka which is supposed
by some to address the deficiencies of the Double Bazooka. The VSWR
bandwidth is greater, but at the expense of even higher stub loss.

Owen

sounds like a regular dipole will do the same for less
always interesting to see different designs and opinions tho!!


On Sat, 08 Sep 2007 20:37:11 -0700, wrote:

On Sep 8, 7:09 pm, Owen Duffy wrote:


My study of a typical Double Bazooka antenna system athttp://www.vk1od.net/DoubleBazooka/index.htmindicates that although it
might have slightly greater VSWR bandwidth (FWIW), it has more loss than
a conventional dipole.



I believe Walter Maxwell also wrote an article about that a few years
back.
There is no free lunch with the double bazookas. I don't use them
myself.
Not so much because of the slight extra loss, more that coax weighs
too much to use as antenna wire unless you have really strong
supports.
Regular wire is also a good bit cheaper. :/
MK

wrote:
I believe Walter Maxwell also wrote an article about that a few years
back.

http://www.w2du.com/r2ch18.pdf
(Sec. 18.3 Resistive Losses)
--
73, Cecil http://www.w5dxp.com

On Sat, 08 Sep 2007 20:31:05 -0700, wrote:


I believe Walter Maxwell also wrote an article about that a few years
back.
There is no free lunch with the double bazookas. I don't use them
myself.
Not so much because of the slight extra loss, more that coax weighs
too much to use as antenna wire unless you have really strong
supports.
Regular wire is also a good bit cheaper. :/
MK

Here's the article:

http://www.w2du.com/r2ch18.pdf

Danny, K6MHE