You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
The Feb 2025 Radioddity Giveaway Results are In! Click Here to see who won!

Reply to thread

Message

Idea for 3 elements only.

Willie, My idea for a 2 element antenna in this post is entirely different then what I think about 3 element mobile designs. I've seen many people make different attempts at getting a mobile director element to work in a 3 element configuration. Insulating the director from the vehicle ground plane by extending it out in front of it, leaves you with half of a director element. This is why your director element is longer then your other elements. Building a metal bracket that is RF bonded to the vehicle places the reflective ground plane behind the director. This causes the radiation currents in this element to favor the rear direction. Exactly what we don't want for a director.

What you should do is fabricate an isulative support out in front of the vehicle to hold a mirror mount bracket. Use the four bolts on the mirror mount to hold it to the insulated support with the notch that would normally mount to the tube on the mirror, facing forward. Remove the plastic washer in the aluminum mirror mount connector so that the top 3/8 thread is shorted to the metal below it.

Then insert a piece of horizontal aluminum tubing about 1/4 wavelength long, inside the mirror mount tube base so that it extends out in front of the director and the vehicle horizontally. Then bend this element down towards a 45 degree angle to improve the VSWR. This lower angled counterpoise on the director will pull the radiation currents in the forward direction. The length of the top and bottom angle half of the director must be equal and should be adjusted for maximum forward gain.

<blockquote data-quote="Shockwave" data-source="post: 300260" data-attributes="member: 10882">Idea for 3 elements only.Willie, My idea for a 2 element antenna in this post is entirely different then what I think about 3 element mobile designs. I&#039;ve seen many people make different attempts at getting a mobile director element to work in a 3 element configuration. Insulating the director from the vehicle ground plane by extending it out in front of it, leaves you with half of a director element. This is why your director element is longer then your other elements. Building a metal bracket that is RF bonded to the vehicle places the reflective ground plane behind the director. This causes the radiation currents in this element to favor the rear direction. Exactly what we don&#039;t want for a director.What you should do is fabricate an isulative support out in front of the vehicle to hold a mirror mount bracket. Use the four bolts on the mirror mount to hold it to the insulated support with the notch that would normally mount to the tube on the mirror, facing forward. Remove the plastic washer in the aluminum mirror mount connector so that the top 3/8 thread is shorted to the metal below it.Then insert a piece of horizontal aluminum tubing about 1/4 wavelength long, inside the mirror mount tube base so that it extends out in front of the director and the vehicle horizontally. Then bend this element down towards a 45 degree angle to improve the VSWR. This lower angled counterpoise on the director will pull the radiation currents in the forward direction. The length of the top and bottom angle half of the director must be equal and should be adjusted for maximum forward gain.</blockquote>

[QUOTE="Shockwave, post: 300260, member: 10882"] [b]Idea for 3 elements only.[/b] Willie, My idea for a 2 element antenna in this post is entirely different then what I think about 3 element mobile designs. I've seen many people make different attempts at getting a mobile director element to work in a 3 element configuration. Insulating the director from the vehicle ground plane by extending it out in front of it, leaves you with half of a director element. This is why your director element is longer then your other elements. Building a metal bracket that is RF bonded to the vehicle places the reflective ground plane behind the director. This causes the radiation currents in this element to favor the rear direction. Exactly what we don't want for a director. What you should do is fabricate an isulative support out in front of the vehicle to hold a mirror mount bracket. Use the four bolts on the mirror mount to hold it to the insulated support with the notch that would normally mount to the tube on the mirror, facing forward. Remove the plastic washer in the aluminum mirror mount connector so that the top 3/8 thread is shorted to the metal below it. Then insert a piece of horizontal aluminum tubing about 1/4 wavelength long, inside the mirror mount tube base so that it extends out in front of the director and the vehicle horizontally. Then bend this element down towards a 45 degree angle to improve the VSWR. This lower angled counterpoise on the director will pull the radiation currents in the forward direction. The length of the top and bottom angle half of the director must be equal and should be adjusted for maximum forward gain. [/QUOTE]

Top Bottom