[TenTec] Fluid motion antenna

[Mark Erbaugh]

Stuart,

According to the website, the moving parts of the elements (copper strips)
are inside fiberglass tubes that do not move.

Mark

----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: <KB2HUK@aol.com>
Cc: <tentec@contesting.com>
Sent: Monday, April 01, 2002 19:11 PM
Subject: [TenTec] Fluid motion antenna


> John,
> This antenna replaces traps or interlaced resonant elements or trap
loading
> for each band with motorized metal tape elements that crank out to half
wave
> on each element, for the band in use.  It is an approach to do away with
> trap losses.
>
> However, it as I understand it, it does not adjust the element to element
> boom spacing of this Yagi.   Thus, the fixed spacing will be a compromise
of
> gain and front to back over a monoband Yagi.  I think it would of
necessity
> be a bit lower in performance to Yagis which have individual elements for
> the bands, such as Force 12 design.  However, it keeps your profile to
only
> 3 elements.  Am not sure what the wind load implications of for the added
> mechanical mechanism.  My concern would be that in areas with freezing
> winter rain and ice, the elements could get hung up, unless they are
> enclosed adequately.  And, would they be locked in length sufficiently to
> withstand wind?  What kind of lifetime do the small motors required have?
>
> I guess the analogy would be to the screwdriver type antenna.  But inside
of
> motorized tap changing on a coil, you are moving the actual element
length.
> A novel idea!
>
> 73,
> Stuart K5KVH
>
>
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