Topband: DX-Enginneering Active Antenna System

[Bill Tippett]

On Fri, Oct 2, 2009 at 12:10 PM, Joe Subich, W4TV <lists at subich.com> wrote:
>
>
> > Bad assumption Joe.
> >
> > "This unit was optimized for the 160 meter amateur band but
> > can be used from below the broadcast band to over 30MHz."
> >
> > http://www.hizantennas.com/controller_4_elements.htm
>
> That still doesn't answer the question.  The 8 element design
> could be used on any band but the phasing was such that it
> was correct only over a narrow band.  The W8JI "crossfire"
> design hold the phasing correct over more than an octave.

Please carefully read Lee's description (asterisks added):

"This controller was designed to connect 4 shortened antennas using
Hi-Z amplifiers into a directional receiving antenna. This new and
unique circuit configuration uses Tri-Phase combining for extra
accurate phasing and amplitude stability.

***This unit uses only two delay lines and provides a form of time
delay phasing that provides more than one band coverage.***

This unit was optimized for the 160 meter amateur band but can be used
from below the broadcast band to over 30MHz. A typical 80 foot square
layout of 20 foot tall elements and Hi-Z amplifiers can provide 12dB
of Relative Directivity Factor and 30 dB of front to back ratio on 160
meters. Of course the best performance depends on the accuracy of the
antenna layout, the accuracy of the connecting and phasing cables, and
any interfering nearby structures. The unit requires +13.8 VDC and
less than 150 milliamps current. It also requires two wires to switch
between the 4 available directions."

http://www.hizantennas.com/controller_4_elements.htm

Lee's documentation includes graphs which include Best 80m RDF, Best
160m RDF and Best 160m F/R RDF (i.e. 3 plots of RDF versus element
spacing).  This helps make 80/160m spacing configuration tradeoffs.
His system definitely covers both 80m and 160m with RDFs ranging from
10.8 to 12.3 on those two bands.  It's most definitely not a "single
band design" as you originally stated.

73,  Bill