[Top] [All Lists]

Re: [TowerTalk] dipole configuration

To: Terry Conboy <>
Subject: Re: [TowerTalk] dipole configuration
From: Blair S Balden <>
Date: Mon, 07 Dec 2009 11:55:35 -0500
List-post: <">>
Thank you, Terry.  And thanks to all who gave ideas.  The double-L looks 
interesting, but I'm not sure the vertical height I have will allow me to use 
it.  My tower is only 40 feet tall, and, to make things worse, the ground 
slopes upward away from the tower in the direction I can use (back yard).  I 
want to keep everything up away from the ground, so that doesn't leave much 
height to work with.  

I appreciate some of the other ideas I got, as well, but I'm trying to avoid 
putting in radials, at least for the moment.

I went ahead with my original thought yesterday - a horizontal dipole with one 
shortened leg loaded with a coil 10 feet out from the feed point.  I wound the 
coil on 3 inch PVC.  I ran out of daylight before getting the antenna 
completely adjusted.  It was a little long, and I had an SWR of 3 at the low 
end of the band, going up as I tuned higher.  My tuner matched it, and I worked 
a station in Rhode island and one in West Virginia (I'm in Michigan).  Not DX, 
obviously, but at least I have something I can use for the band.

I went out this morning and took a few turns off the coil.  SWR is now flat at 
about 1820 kHz.  Gets to 3 at about 1870 kHz.  Looks good, as I'm probably 
going to be using mostly CW.  All I need to do now is solder up my connections 
and secure the coil a little better.  I'll try this out for a while and maybe 
do something better for low-angle radiation later.

Thanks again to everyone.  Time for me to go to work!  

73 de Blair, NP2F

----- Original Message -----
From: Terry Conboy <>
Date: Sunday, December 6, 2009 7:23 pm
Subject: Re: [TowerTalk] dipole configuration

> Blair,
> You've gotten some good inputs on your question.  Vertical 
> polarization 
> is definitely the way to go on 160m.  Given your space 
> constraints, the 
> K2KQ "Double-L", would be a good antenna for you.  See 
> and 
>   K2KQ shows 
> a dual 
> band (80-160) version, but you can just leave off the 80m wires if 
> that 
> band isn't of interest.  If you can't get the full height, you can 
> lengthen the horizontal wires to keep the total length the same.  
> The 
> impedance will be a bit lower with less vertical height.
> N0HR has done some modeling of this antenna and includes radiation 
> patterns:
> This antenna has a lot of low angle signal, but also fills in the 
> null 
> somewhat at high angles, making it good for short haul work, too.  
> It 
> will have a lot more bandwidth than an approach using loading 
> coils and 
> much more efficient than a low dipole.
> 73, Terry N6RY
> On 2009-12-04 5:10 AM, Blair S Balden NP2F wrote:
> > I'm getting set to put up a wire dipole for 160 meters.  I'm 
> considering 2 options, and I wanted to hear which one you guys 
> think might be better.  The feed point will be about 38 feet up on 
> the side of a tower near the house.  From there, I have just 
> enough room to stretch out a full quarter wave to the back edge of 
> my property, where I can get about 25 - 30 feet of height in a 
> tree at the other end.  So this leg of the dipole will be pretty 
> much horizontal. 
> >
> > For the other leg, I don't have that much room.  I will need to 
> put in a loading coil.  I have about 60 feet to a tree in the 
> front yard, where I can get about 25 feet of height.  This is what 
> I was planning, but I also thought about bringing that leg 
> straight down from the feed point.  In that case, the antenna 
> would have one full-length horizontal leg and one short (about 30 
> foot) vertical leg with a loading coil.
> >  
> > Do you think anything would be gained by having part of the 
> antenna vertical?  Would I get some lower-angle radiation if I did 
> it that way?  Or would it work better more or less horizontal?
> >
> >   


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>