Hello, everyone. I'm enquiring as to whether anyone has done NEC2/NEC4
modeling on the subject antenna (including a tower mounting) and operating
on the ham bands. Do you have tabulated driving point (antenna feedpoint)
and gain data that you might share? Thanks for your time and comment.
Sincerely, and 73s from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

J. B. Wood wrote:
Hello, everyone. I'm enquiring as to whether anyone has done NEC2/NEC4
modeling on the subject antenna (including a tower mounting) and operating
on the ham bands. Do you have tabulated driving point (antenna feedpoint)
and gain data that you might share? Thanks for your time and comment.
Sincerely, and 73s from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

I suggest you contact the manufacturer (http://www.hexbeam.com), if you
haven't already. They might have some information they'd share.

Roy Lewallen, W7EL

In article ,
wrote:

J. B. Wood wrote:
Hello, everyone. I'm enquiring as to whether anyone has done NEC2/NEC4
modeling on the subject antenna (including a tower mounting) and operating
on the ham bands. Do you have tabulated driving point (antenna feedpoint)
and gain data that you might share? Thanks for your time and comment.
Sincerely, and 73s from N4GGO,

John Wood (Code 5550) e-mail:

Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

I suggest you contact the manufacturer (http://www.hexbeam.com), if you
haven't already. They might have some information they'd share.

Roy Lewallen, W7EL

Thanks for responding, Roy. Some hams are apparently assembling the
antenna from their own materials rather than buying the antenna outright.
Of all the folks that I can think of that might have done a MoM analysis
of this antenna, you come to my mind first. 73s,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

John,

Take a look at my web site if you haven't already found it. There are
2 pages devoted to modelling the hexbeam and there's an EZNEC file for
a five-band version you can download:

http://www.karinya.net/g3txq/hexbeam/eznec1/
http://www.karinya.net/g3txq/hexbeam/eznec2/

73,
Steve G3TXQ

wrote:
John,

Take a look at my web site if you haven't already found it. There are
2 pages devoted to modelling the hexbeam and there's an EZNEC file for
a five-band version you can download:

http://www.karinya.net/g3txq/hexbeam/eznec1/
http://www.karinya.net/g3txq/hexbeam/eznec2/

73,
Steve G3TXQ


Nicely done, Steve. Thanks.

tom
K0TAR

J. B. Wood wrote:
Hello, everyone. I'm enquiring as to whether anyone has done NEC2/NEC4
modeling on the subject antenna (including a tower mounting) and operating
on the ham bands.

Interesting designs, I hadn't seen them before.
For a hand-held DF sniffer on 2m, might there be
compactness advantages? What would the approximate
dimensions of be of a hexbeam on 2 metres?

Clifford Heath, VK3CLF

Clifford,

Turn radius is about 12.5" for a 2m broadband hex.

It should be possible to get very deep and narrow F/B nulls by
adjusting the Driver/Reflector end spacing at some cost to the VSWR.

Steve G3TXQ

wrote:
John,

Take a look at my web site if you haven't already found it. There are
2 pages devoted to modelling the hexbeam and there's an EZNEC file for
a five-band version you can download:

http://www.karinya.net/g3txq/hexbeam/eznec1/
http://www.karinya.net/g3txq/hexbeam/eznec2/

73,
Steve G3TXQ

Now, that's what I'm talkin' about! Great job, Steve. 73's,

wrote:
Turn radius is about 12.5" for a 2m broadband hex.

Sorry Steve, I see a pair of W shapes, or a W driver and
4-of-6 hexagon reflector. Which measurement is 12.5" - is
this the radius (length) of the hexagon arms (and hence
also of all the peripheral segments)?

It should be possible to get very deep and narrow F/B nulls by
adjusting the Driver/Reflector end spacing at some cost to the VSWR.

If I'm reading you right, the gap between the ends is the
salient factor here. Suggestions on how big a gap to try
first? Something like 3cm?

Sorry for the newbie-ness. Been doing electronics for 30
years, but only now getting into radio and have never tuned
an antenna. Sorta understand EM fields, but don't have any
RF test gear yet, except for my very nice VK3YNG sniffer
(google it). Maybe I should borrow/buy one of the little
fox-or transmitters to tune up an antenna, but it'll be too
late for this weekend's national foxhunt champs in Mt Gambier.

Clifford Heath VK3CLF.

Clifford,

There are two styles of hexbeam: the older design which has a W-shape
Driver and a W-shape Reflector, and which I call the "classic" on my
web site; and my newer broadband design which has a W-shape Driver and
a U-shape Reflector.

I found in my lab notebook a 2m version of the broadband style; its
dimensions a half-Driver 21"; Reflector 40"; end gap 2.5". I think
I assumed wire construction using #14 bare copper. That would give a
hexagon radius of 12.5".

When I model this with EZNEC I see about 3.8dBd Forward Gain and 19dB
F/B with VSWR=1.4. The problem is that the rearward response is very
smooth and "well behaved" so probably not much use for DF.

If I increase the end gap to 5" the Forward Gain and F/B remain about
the same, but the azimuth pattern devlops deep side nulls (38dB) at
plus and minus 130 degrees which may be useful. The VSWR deteriorates
to 1.8:1.

Hopefully that may give you a starting point for experimentation. If I
get a chance I'll try some modelling experiments on the classic design
also.

73,
Steve G3TXQ