[TenTec] Re: Fluid motion antenna

[Dave Kamp, KW0D]

Okay, this is off the T-T topic, but since there's enough rattling around,
I'll put in my observations.

The FluidMotion antenna was on display at the Dayton Hamvention last year.
It is a very interesting machine.

Each element consists of a pair of fiberglass tubes, with a box located at
the middle.  Inside the box is a side-by-side pair of spools, upon which
are wrapped a copper clad (but I believe the material is actually SS)
perforated foil approximately 3/8" wide, by mebbie 0.080' thick or so, by
pretty-darned-long.  The spools are positioned so that the foil strips will
tail out into the fiberglass tubes (one foil to the east, other to the
west).  The foil strips are driven out at identical rates by a sheave with
pins, like the advancing mechanism on 35mm film.  The sheaves are driven by
a stepper motor.  On the bitter end of each strip is a plastic tab, which
keeps the strip from getting hung up inside the fiberglass element tubes.

Each element pair has it's own stepper motor, and at the operating station
is a control box, which controls each of the stepper motors to change
element lengths.  Standard configurations are preprogrammed into the box,
and changing tunings is as easy as tweaking any of the elements' lengths
from the control box.  There is also a 'hot button' on the panel which will
swap the elements' dimensions to reverse the antenna's heading by 180
degrees... in under a second or three.

>From what I was told by the designers, one can configure 'their own'
antenna dimensions and save them in the controller's memory.  They also
make the antenna available as a basic dipole, a basic 3-element, or even
more elements, if you wanna work with their guys to make it happen.

As far as not having adjustable spacings between the elements, the answer I
got was yes and no... you can configure the beam manually (like, when you
assemble it), but as far as having different element spacings later, well,
it's no different from your TH3 or TA33... it's the same a compromise
there.  What you CAN do is retract an element to a non-functional length,
and just use it as a 2-el, or even as a dipole.

In all, it's a slick idea, and the mechanism worked very well at the
display.  If I had a fountain of money, I'd dip some out and mount ten or
so of these elements on a 50-foot (Telrex-like) boom, network the
controller to my PCs, and spend some quality time with an antenna program
to make a bunch of configurations for everything up through 2m... take down
the 6-el 6m Telrex, and find a new home for the TH3SR... and start enjoying
massive monobanders...

DK  :-)

73's from KW0D Dave in LeClaire, Iowa