Seco Systems
Tornado Tuner© 8040D
The flagship of the Tornado Tuner© line.
The 8040D is a dual coil model with a
shorting switch designed around Force
12's Sigma 80 vertical dipole.   
By replacing the stock fixed coils with
the Tornado Tuner© you are not only
able to remotely tune the full 80/75
meter band, you are able to tune most
of the 40 meter band with the shorting
switches engaged.
  The Tornado
Tuner© 80D does not have the shorting
switches and is very popular on 80/75
meter rotatable dipoles.
- The Tornado Tuner© is manufactured right here in the USA.  The internal
components are injection molded by a local injection molding shop and the
housing is constructed from PVC tubing with a coating of plastic paint for UV
protection.  Quality and craftsmanship is our highest priority!
- The Tornado Tuner© can be configured for single coil and dual coil
applications.   The dual coil models use a common lead screw to expand and
contract the coils simultaneously.  
- The coil diameter is approximately 4.5 inches and is fixed. The length of the
coils can be varied up to 40 turns.  The lead screw and housing can be made
to any length.  
- The coils on the standard model are manufactured from aluminum tubing.  
Copper may be used also.  
- We also manufacture a manual version of all our tuners.  The manual
version uses a crank to very the inductance and is an inexpensive way to
fine tune an antenna for a single spot on the band.
Tornado Tuner© Basic Design Parameters