Towertalk
[Top] [All Lists]

Re: [TowerTalk] reflector for 75 meter inverted vee

To: towertalk@contesting.com
Subject: Re: [TowerTalk] reflector for 75 meter inverted vee
From: K4SAV <RadioIR@charter.net>
Date: Wed, 04 Oct 2006 12:03:40 -0500
List-post: <mailto:towertalk@contesting.com>
Adding a reflector sounds like a wasted effort. EZNEC says a gain 
increase of about 0.3 dB straight up.

Assuming an inverted vee with the ends 30 feet below the apex, the 
height for max straight up gain is about 65 ft. Your antenna at 95 ft is 
only 1.5 dB below that for signals at 90 degrees elevation.  The 95 ft 
antenna does have the same gain but the take off angle is about 46 degrees.

Even taking a lower antenna and feeding both antennas at various phase 
angles, I was unable to obtain any significant gain increase at 90 
degrees elevation. The simplest antenna I can think of that will 
increase the gain at 90 degrees elevation is a full wave horizontal loop 
at 50 feet. That will give you about 2.5 dB more gain than your inverted 
vee at 95 feet.

It is possible to build arrays that squirt the signal straight up with 
significant gain, but the beamwidth is fairly narrow, and these antennas 
don't seem to have any applications in ham radio.

Jerry, K4SAV

Joe Barnes wrote:

>I am considering putting up a wire about 1/4 wave below my 75 meter 
>inverted vee that is 10 percent longer than the inverted vee to use it 
>as a reflector for closer in ( within 700 miles or so) communications. 
>Does anyone have any experience with such a thing? The inverted vee is 
>at 95 feet at its apex. Thank you, joe barnes N4JBK
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
>  
>
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

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