Reflector/Director for dipole

This forum provides help with antenna installation, as well as guidance on selecting the right antenna for your radio or mobile setup.
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Slim Pickins
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Joined: November 8th, 2009, 7:10 am
Handle: Slim Pickins
Real Name: Paul
Call Sign: VE1PEW
Radio: Realistic Navajo 457
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#289253

Post by Slim Pickins »

goofy wrote:One thing you need to know, the impedance load of a a two or three element yagi (essentially what you are building) is not 50 ohms, like a dipole. It is actually lower I think. This will affect SWR..

One antenna you can build that still presents a 50 ohm match, but gives you directivity and gain over a dipole is the Moxon. I am working on a homebrew of this myself.

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I have seen the moxon antennas and even have considered building one. It looks like a fairly easy build. Another one you may be interested in is the Spyder Beam or G4ZU as some call it. It is basically a 3 element yagi with the director and reflector bent toward the driven element. Construction is similar to the Moxon. I haven't done these builds yet because I am busy gathering materials for a 4 element Quad that I want to build. I am trying to do it with garbage day found materials and not spend anything on it except maybe the hardware to fasten it all together. Turns out half the fun is in finding the materials, especially since you don't know what the materials are until you see them. My work takes me all over the city and I can be just about anywhere any given day so I just go a little early and drive slow through the residential areas that I need to pass through anyway.
73,Slim

Insanity is hereditary......you get it from your children.
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goofy
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#289281

Post by goofy »

4 element quad? - Very ambitious of you..

I'm going to start with the moxon and see how that plays out, and if I get it going, maybe a two element quad at some point.

I'm thinking I'm going to go schedule 40 PVC for my moxon, like this one [ external image ], the stuff is dirt cheap.
And probably one of those 23' expandable painters poles for the tower (or maybe just 2 ten foot sections of a thicker schedule 40).

The wire and the feed point insulator will probably be the only two things that are purpose built for communications
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