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Re: Topband: Topband :"T"

To: w2pm@aol.com
Subject: Re: Topband: Topband :"T"
From: "Herbert L. Schoenbohm" <herbs@vitelcom.net>
Reply-to: herbs@vitelcom.net
Date: Thu, 09 Oct 2008 20:15:11 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>

w2pm@aol.com wrote:
>
>
>  
> .  So give some consideration to either a
> square or delta (triangular) top hat supported by corner supports that 
> drop
> the vertical wire.  Two cross wires (on the square wire top hat) with the
> vertical drop in the center or three intersecting wires for the 
> triangle top
> hat should save space, improve efficiency, and allow for a lower vertical
> overall height.  The "T" is simple and easy but does require some real
> estate, whereas a smaller profile top hat will do the same thing or 
> better
> (cancelling high angle useless radiation) as described. 
> Herb Schoenbohm, KV4FZ
>
> Pete W2PM Replies:
>
> But how can a top hat device be supported with a vertical wire?  Ive 
> seen some on 60 foot vertical masts but I don't think you can do this 
> with a wire or a small gauge tapered 60 ft mast.   This is why I 
> wonder if under these circumstances a top load coil with a shortened 
> (100 ft top wire) would be more feasible as you can hang the coil from 
> the rope which holds up the vertical wire...
>
> Pete,  the wire flat square, rectangle, or triangle quasi top hat 
> supports the vertical drop wire, rather then a center vertical  
> holding up the top hat. No center pipe or pole are needed. The wires 
> that forms the top hat are supported by wooden mast or trees carried 
> up on a  nylon rope halyard and can be lowered to the ground for easy 
> maintainence.  The skelton flat top will provide considerably more 
> capacity to the ground capture area then a "T" IMHO and make the lot 
> size (except for the ground radials) more reasonable for a high 
> performance 160 meter vertical.  Top loading a mast or evena tower 
> with sloping wires has a point of diminishing returns due to 
> cancelation of the very same element you want to radiate. I believe 
> past 20 per cent of the over all mast height is about it.  However, a 
> truely flat top T, or the flat top box or triangle will not work to 
> the detriment of the vertical portion or vertical dropwire.

Herb, KV4FZ
>
>
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