Does a Hexbeam work better than a dipole?
fch
OC_CAM's Razor
> Is it even directional?
Yes it is, so you have to rotate it. It is a beam, much
like the X-beams of years past. But like the quad, once
you have the support system, you can add wires for multiple
bands using the same supports. As a single band antenna,
it doesn't have much to offer. As a multi-band antenna,
it is a pretty cute idea.
--
cheers, CAM http://www.qsl.net/w5dxp
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Rick Littlefield
I built one for 10 meters a while back. I think it had about 5 dBi gain with
front-to-back ranging from 12dB to over 20 dB--depending on frequency (dipole
has 2.15 dBi). It performed identically to my Moxon rectangle in side-by-side
comparisons and the front-to-back was quite helpful for eliminating QRM from
the south when the band was open to Europe here on the east coast. My 3-element
yagi did perceptibly better both in gain and front-to-back. I like the
Hexbeam...think its mechanical design is clever and like the way it blends in.
Rick K1BQT
Dan Richardson
Paulo Marcondes
> My 3-element
> yagi did perceptibly better both in gain and front-to-back. I like the
> Hexbeam...think its mechanical design is clever and like the way it blends in.
Yes...
Mechanical design is clever. I think it may be quite easy to
align it properly.
It is my preferred antenna project by now. As said
previoulsy on this NG, I am working to get one built. I
preferred it over a Yagi because ease of construction, since
I have no access to a suitable workshop to fabricate the
aluminium elements.
The HB, on the other hand is just fiberglass (or bamboo, or
doweling) and wire. We all have the tool to work with wire,
and maybe even fiberglass. So... ease of construction is
maximum...Left behind dipoles, of course.
Being a high-dweller, I have no way to put wire dipoles or
big wire antennas, so a beam is a must. The station will
probably never be a big gun but certainly more than enough
for rag-chewing.
--
Paulo E.P. Marcondes
pe...@osite.com.br
fch
offer?
Does it even work better than a dipole?
Have you ever modeled one on a program?
Does it work 50% as well as a yagi, 75%??
fch
How much better did the yagi perform than the hexbeam?
1 s unit??
OC_CAM's Razor
> What do you mean the hexbeam doesn't have much to
> offer?
As a single-band antenna, it doesn't have much to offer over
an X-beam or a two-element Yagi. The cost and performance of
all three antennas is approximately the same and all three
antennas require a rotor. It has all the advantages and
disadvantages of most other two-element beams. That's what
I meant. Sorry if that wasn't clear. I'm a man of few words.
Rick Littlefield
Not what I reported. A couple dBm is the average I measured using the
sample-and-hold signal strength funciton on a Ten-Tec commercial receiver. In
my view, the primary advantage of a small yagi is the rejection of unwanted
signals off the back.
Rick K1BQT
fch
I'm not sure what an X beam is.
How much performance difference is there between a 2 and 3 element yagi?
OC_CAM's Razor
> I think the hexbeam is much more expensive than the others.
> I'm not sure what an X beam is.
Page 33-15, 1993 ARRL Handbook. X-beam Vs hexbeam below
|\ /| /\ /\
| \ / | / \ / \
| \/ | / \/ \
| /\ | \ /\ /
| / \ | \ / \ /
|/ \| \/ \/
> How much performance difference is there between a 2 and 3 element yagi?
Roughly 2.5 dB, roughly half an S-unit.
Brian Kelly
> fch wrote:
> > I think the hexbeam is much more expensive than the others.
> > I'm not sure what an X beam is.
>
> Page 33-15, 1993 ARRL Handbook. X-beam Vs hexbeam below
>
> |\ /| /\ /\
> | \ / | / \ / \
> | \/ | / \/ \
>
> | /\ | \ /\ /
> | / \ | \ / \ /
> |/ \| \/ \/
>
> > How much performance difference is there between a 2 and 3 element yagi?
>
> Roughly 2.5 dB, roughly half an S-unit.
As you well know Cecil gain (or a lack therof)is not the the only
consideration when it comes to rotatable beams. Like the old saw goes
"ya can't work 'em if ya can't hear 'em" and the decent front-to-back
ratios (2-3 s-units or more) two elemet beams exhibit often make the
difference between being able to copy the guy or not. I'll take a
unity gain steerable beam with a 25 dB F/B ratio any day over a dipole
or a vertical. One can always get more gain with the Variac.
w3rv
Floyd Sense
now, which I guess makes me an old-timer when it comes to the Hexbeam.
Before purchasing the antenna, I evaluated all the other 5 band commercially
made antennas as well as the various compact wire beam designs requiring
homebrew construction. If my circumstances had not ruled out a 100' tower
and the gleaming aluminum antenna structures that I was used to, I would
likely not have chosen the Hexbeam. Here's a link to a site where I lay out
the advantages as I saw them three years ago, and still do.
http://home.sprintmail.com/~sentek/hexpage1.htm
The front/back ratio, and perhaps the gain (?) varies from one end of the
band(s) to the other, with maximum f/b occurring low in the CW band on the
five bands. While I see good front/back low in the bands, there is precious
little at the top of some of the SSB portion of the bands, most notably 20
meters. On the other hand, the design results in a fairly flat SWR across
the entire band(s). I won't enter into a discussion of the exact numbers,
since that always results in attacks from the engineers in the group. The
numbers I see are not as good as those described by Lew McCoy in his CQ
article a couple of years ago, but they are comparable to other 2 element
beam designs.
Note that the turning radius of a 20 meter hexbeam is only around 9.5 feet,
which makes it smaller in the longest direction than a dipole and
substantially smaller than a 2 element 20 meter yagi.
At any rate, I doubt that anyone will argue the fact that any antenna with
gain, and particularly a rotatable antenna, will always be better than a
dipole. If you have sufficient funds and no restrictions on what you can
erect in your area, then put up the biggest, highest yagi array you can find
or build. You'll be amazed at what you'll hear compared to the dipole!
K8AC
"fch" <n...@hle.com> wrote in message news:3E6A46D5...@hle.com...
> Is it even directional?
>
Brian Kelly
Here's the mother lode of tech info on the whole category of compact
end-coupled beams like the hex.
w3rv
Rick Littlefield
antnenas for Com Quarterly!
Brian Kelly
> Dang...wish I'd thought of that! LB wrote a whole series of articles on these
> antnenas for Com Quarterly!
>
> http://www.cebik.com/4.html
I live in his website. I've downloaded a lot of it.
Do you know if he published those articles before 1999? The League
offers a CD which covers all issues of QEX from 1981 thru 1998. I'd
grab that if it includes those articles.
I gotta build one of 'em, either a triband hex or a Moxon. Perchance
have you ever run into a triband Moxon (10 nested inside 15 nested
inside 20 on the same four spreaders)??
Tnx,
Brian w3rv