Hex Beam by K4KIO
Site publication date
12/2007
The New G3TXQ Broad Band Hex Beam vs the Classic hexbeam

The classic hexbeam is a proven winner among those who have built or bought one. Check out
the reviews on eHam.net for comments of many users. However, the classic hexbeam has a
significant shortcoming that is a result of its compressed configuration. It is rather narrow banded.
In fact, if you tune the classic hexbeam for use on the SSB portion of the larger bands such as 20
or 15 meters it will perform quite well. But you will find that the front to back performance on the
CW end of the band is quite mediocre if not downright unacceptable. You can tune it for the middle
of the band but then it will be only average in performance on both the SSB and CW sub bands.

In November 2007, Steve Hunt, G3TXQ, developed a major improvement in the classic hexbeam
to overcome these bandwidth limitations. The new G3TXQ hex beam is much broader in its
performance and as a result will deliver quite good front to back performance as well as low SWR
over the entire range of frequencies of the larger bands. Below are charts that illustrate the
differences in the classic and broadband hex beams on 20 meters. The only penalty to be paid for
this improved performance is a slightly larger diameter of the broad band. The five band classic
hexbeam for 10, 12, 15, 17, 20 meters is about 19 feet in diameter; the broadband is 22 feet.

This minor difference in size for such a major improvement in performance causes me to
recommend the G3TXQ hex beam over the classic. I have modeled both, I have built both, I have
tested both and I have used both. And I am convinced that the G3TXQ broad band beam is better.

Having said that, there is much history with the classic design; it is widely used and acclaimed. So
I included guidelines for constructing one like the one I built for myself. Find those classic hex
beam guidelines here. But for those who will only be satisfied with the best, you can follow these
steps to build the G3TXQ broad band hex beam. If you would like a better understanding of both
the classic as well as the broad band hex beam, I strongly urge you to check out the web site of
Steve Hunt, G3TXQ . At the urging of the late L.B. Cebik, W4RNL, Steve recently authored an article
featuring the broad band hex beam in the December 2007 edition of the ham radio on line
antenna magazine, AntenneX.  Below is a comparison of the classic and the broad band hex
beams.
Top view of a five band classic hex beam
antenna showing wires only with no
spreaders or other supporting structure.
Diameter is 19 feet
Top view of a five band G3TXQ hex beam
antenna showing wires only with no
spreaders or other supporting structure.
Diameter is 22 feet
The SWR of the G3TXQ hex beam is dramatically better on the low end of the band
making it easier to couple the transceiver to the antenna for maximal power transfer.
The forward gain of the G3TXQ hex beam is slightly better than the classic design.
The front/back gain ratio of the  G3TXQ hex beam is dramatically better than the classic
design. This means that unwanted signals coming into the transceiver from the back of
the beam will be much less than with the classic hex beam.
Azimuthal radiation patterns for the classic hex beam and for the G3TXQ hex beam. Note
the slightly superior forward gain and the significantly superior front/back performance
of the G3TXQ hex beam.
Building the G3TXQ Broad Band Hex Beam
Classic

__Construction of the G3TXQ broad   
__band hex beam is easier than the
__classic hex beam.

  • No terminals for the reflector on
    the center post
  • Only two end spacers per band
    rather than four
  • Reflector, driver and spacers are
    a single loop making
    adjustment much simpler
  • Tuning is not as critical because
    the bandwidth is broader.
Hear the difference in signal level from back of
the hex beam as compared to the front. This is an
important measure of the beam performance as
you generally want less signals coming in from
the undesired directions.

These audio clips were recorded by G3TXQ in
January 2008 from switching back and forth every
3 - 5 seconds between one hex beam and
another aimed 180 degrees to the rear.
Station in Iceland on
20 Meters
Station in USA on
17 Meters
On air recordings to demonstrate front to back
performance of the broad band hex beam
G3TXQ
Data for five band hex beams on 20 meters at 30 feet above good ground. Azimuthal patterns
at 29 degrees elevation. SWR for 50 ohm feed.
Note that the peak of front/back performance of
the classic version occurs at a frequency that is
relatively high on the SWR curve making it
necessaray to compromise between optimal
SWR and best F/B. Whereas, with the broadband
version, the front/back performance peaks at the
lowest SWR with the result that there is no need
to compromise between these two major goals in
beam perfomance.