[TowerTalk] Inverted Vee
k3nd at yahoo.com
Thu Aug 4 13:03:08 PDT 2011
From: "larryjspammenot at teleport.com" <larryj at teleport.com>
To: towertalk at contesting.com
Sent: Thursday, August 4, 2011 1:58 PM
Subject: Re: [TowerTalk] Inverted Vee
Does anyone actually offer these baluns for sale as already-built units, or as a complete kit, without having to go to each individual manufacturer and order just the pieces?
>From: K8RI on TT <k8ri-on-towertalk at tm.net>
>Sent: Aug 3, 2011 4:44 PM
>To: towertalk at contesting.com
>Subject: Re: [TowerTalk] Inverted Vee
>On 8/3/2011 12:50 PM, John F. wrote:
>> As you know, an inverted vee for a given freq is a balanced antenna with
>> essentially equal current and voltage on both legs. Grounding one leg
>> at or near the feedpoint will destroy that balance. Depending on the
>> height and freq, it will be omni-directional or directional broadside to
>> the legs. The angle of radiation is also dependent upon the height/freq
>> and angle between the legs (ideally a minimum of 110 degrees).
>> Using a balun ( I assume 1:1/ choke type) may or may not be beneficial,
>I run current baluns on almost everything now days and the feedlines
>have their shields grounded to the tower top and bottom. With an
>inverted V the ground is quite close to the choke and the antenna
>connects to the current balun within just a few inches. The baluns are
>designed using Jim Brown's tutorial (watch out for line wrap.)
>BTW for the center fed, sloping, fan dipole on 75, I have one choke
>balun at the feed point and one where the feed line reaches the tower.
>I've not run into any apparent problems.
>> depending on how close the legs are to the tower and the ground. It may
>> help keep RF from flowing on the outside of the coax. I'd just put it
>> up and see what happens.
>> GL, and 73
>> John W4II
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>> TowerTalk at contesting.com
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