Stations that I spoke to, who were using this antenna
appeared to be very happy with the performance, and as I
could observe about 5 S points f/b ratio on most of their
signals, I was hooked...!
I decided one Saturday
morning, to build a monoband 17M Hexagon just for evaluation
purposes. If the exercise was a success, I would build a 30
and 40M interlaced version.
I proceeded as
Saturday 18th August 2001
I took one of the timber
end "cheeks" from an empty coax cable drum, drew
lines from the centre at 60 degree intervals, and drilled two
holes each side of these lines.
I took six glassfibre rods
about 8ft long, and 1/2 ins O/D tapering to about 1/8th ins
O/D, and tied them to the timber hub using TY Wraps as in the
I cut a driven element to
the formula 468/f (wrong formula as it turned out...) and
attached it to the glass fibre arms, followed by the
reflector cut 3 % larger..
airborne at about 5ft high....!! Resonance all wrong...Swift
recalculations...New formula is 520/f...Made the reflector 4%
better.....Resonant in the band..f/b could be much
better...only 3 S points...We'll get that right soon.. HEX at
15ft high...Quad at 35ft high..HEX about 1 S point down on
the quad....HMmmmmm...That's not bad...Looks as if this could
be what I need on 40 and 30M..
If you guys n'
gals are NOT homebrewers (tut tut..! Shame on you) you may be
interested/relieved to know that these antennae are produced
commercially by Traffie
lots of info and pics there of course. I have commented to a number of
commercial HEX-BEAM users that they appeared to me to be a
bit expensive. ALL assured me that they are very
happy with the product, and that they are built to an
extremely high standard..
Here's a couple pics
of Bill W5ONX's homebrew HEX... I have worked him on it, and it works
a treat. You can probably catch him on 17m..
And this is Brian 7Q7BP and Janet
7Q7YL's fine HEX atop their homebrew tower..
What a beautiful QTH...!
The above antenna was an experiment... It confirmed for me the fact that
this is an antenna that works extremely well, in spite of the fact that it
is really small and tidy.... HOWEVER...! I am NOT an expert on the
Hexagonal Beam. If you need more information, you should join the Hex-beam
afficionados at http://groups.yahoo.com/group/hex-beam/
.. There you will find the real experts VK2DPD,
DL7IO etc, etc... Many of these guys have homebrewed mono and multiband
HEXs, and they now have uncovered pretty well all of the secrets..
Not all are homebrewers of
course..Many of the subscribers are satisfied users of the commercial
product from Mike Traffie at Traffie
> I want to be sure that I have
the formula correct 520/f is the driven
> element formula. The Reflector is then made 4% larger than
> that correct?
Nope.. As I stated above , my formula was
"off the mark".... The guys on the HEX reflector all agree the
Driven Element = 6180/Freq
Reflector = 6262/Freq
Tip Space (Driven Element) = 102/Freq
Tip Space (Reflector) = 65/Freq
Overall Tip Space = 145/Freq
Answers in inches...
(A pic to explain the Tip
spacing formulae.. )
>If this is so, then won't the
reflector be a bit higher
> than the driven element?
No.. The elements for each band will be at
the same height, but each band will be at a slightly different height to
the others bands.
> I take it the lower frequency
bands are mounted higher up on the center
> post. Is there a critical distance by which the bands are
> height along the center post?
This will depend on how much
"bend" you have on the spreaders.. The bend
depends on how stiff the spreaders are. There is a bend on the spreaders
that they will pull on the elements to keep them taut.. The stiffer the
arms, the less bend you need. (and the shorter the centre pole..)
>Or is it just by where they fall along
> the bend of the arms?
Just by where they fall along the bend of
the arms ...
> Is there much interaction
between the wires of the band you are using,
> versus the unused bands? Does this have to be taken into
> designing multi band antennas?
As in ANY multiband antenna, there is
interaction between harmonically related bands (e.g 20 and 10m, or 40 and
15m etc) and also when the bands are very close to each other in
frequency. (e.g 10 and 12m). This can be greatly reduced by proper design.
Using a choke balun is a good start..
> How does one calculate the length of the spreaders?
Here's a quick example...say 20m..
The above formula makes the driven element
36ft 3ins long (14.2mHz). divide
that by 4 to give you the length of a side on the equilateral triangles,
which equals 9ft 3/4ins .That makes the "wingspan" 18ft 1 1/2
>Is there a proper
> amount of bowing?
The arms would have to be a
bit longer than the radius, so as to get a
"bow" on them, This bending of the arms, is what keeps the
The stiffer the arms, the less "bow" you need.. For 20m I'd make
about 10ft long..
The tip spacing is critical as regards f/b ratio.. I've attached a pic to
explain the formulae..
> Seems like a fun project.
Yep...Like most antenna projects it can
also be confusing..frustrating..dangerous...exhilerating...educational and