FAQ's
1. Why are these measurements different from those I have
seen on other web sites?
A. Differences can be due to differences in wire gauge used,
design frequency selected, whether the designer sought to
minimize SWR vs optimizing front/back performance (as is done
here).
2. Are the wire lengths critical?
A. Well, if you change the wire length for each half reflector on 10M
by one inch, it changes the design frequency by about 260 kHz.
Two inches would be about 520 kHz, and so on. You can do a
simple ratio of frequencies to figure the change in wire lengths.
(Remember, increasing frequency requires decreasing wire length and
vice versa.)
If you change the reflector lengths be sure and do the same for
the driver wires.
3. How important are the end spaces?
A. Fairly important. They affect impedance of the antenna and also
front/back performance. A half inch discrepancy won't kill you but
don't double the spaces.
4. What if I want to use a different gauge of wire than 16 gauge?
A. That is fine. Just use the Conversion Table on this page to
scale all the wire lengths shown here for your particular wire
thickness. Leave the end spaces as they are shown here.
5. How high should the Hexbeam be?
A. Higher is better for DX generally as it reduces the takeoff angle
of the main RF lobe. However, the hexbeam can be quite effective
even at modest heights.
6. What about use of steel wire or aluminum instead of copper?
A. You will need new dimensions based on conductivity of those
materials. The dimensions here are strictly for copper.
7. What about stranded wire or solid wire?
A. Either is fine.
8. What about insulated wire?
A. You can probably use it but I wouldn't depend on these
specifications which are based on bare copper wire.
9. How important is spacing on the center post?
A. Post spacing is mainly determined by the geometry of your
particular hexbeam. Try to get your wires generally parallel, level
with the ground, symmetrical, etc. Spacing can become a
problem if they are too close. In particular, it has been found by
some that if the 10 meter wires are too close to the 12 meter
wires, the two bands can interact with each other. It is hard to get
the specified 4 inch spacing between 12 and 10 meters while
keeping the 10 meter wires parallel. That's OK; just pull the wires
down the post a bit; performance will be better.
10. Should I feed the hexbeam at the top or the bottom?
A. Top feeding will provide better results overall.
11. Should I connect the bands with wire or coax?
A. Coax will provide better results. Use 50 ohm coax.
12. Do I need a balun?
A. I have done with and done without and results seem about the
same. Others feel it is important.
13. What wire lengths do I use for a hexbeam for the entire
band?
A. Just strike an average between the lower half and upper half
lengths in the table. But note the charts. The hexbeam optimal
front/back performance is pretty narrow and you will be putting
your "sweet spot" in the middle of the band. That is a good choice
if you plan to operate both CW and phone.
14. Can I use the table above for a single band hexbeam?
A. Yes, the single band lengths would be just a slight bit longer.
Add about 1/2 percent.
15. Where can I learn more about the hexbeam theory?
A. Visit the web site of Steve, G3TXQ.
1. Why are these measurements different from those I have
seen on other web sites?
A. Differences can be due to differences in wire gauge used,
design frequency selected, whether the designer sought to
minimize SWR vs optimizing front/back performance (as is done
here).
2. Are the wire lengths critical?
A. Well, if you change the wire length for each half reflector on 10M
by one inch, it changes the design frequency by about 260 kHz.
Two inches would be about 520 kHz, and so on. You can do a
simple ratio of frequencies to figure the change in wire lengths.
- Change in wire length(+,-) = Change in frequency(-,+) X Orig.
wire length / Original frequency
(Remember, increasing frequency requires decreasing wire length and
vice versa.)
If you change the reflector lengths be sure and do the same for
the driver wires.
3. How important are the end spaces?
A. Fairly important. They affect impedance of the antenna and also
front/back performance. A half inch discrepancy won't kill you but
don't double the spaces.
4. What if I want to use a different gauge of wire than 16 gauge?
A. That is fine. Just use the Conversion Table on this page to
scale all the wire lengths shown here for your particular wire
thickness. Leave the end spaces as they are shown here.
5. How high should the Hexbeam be?
A. Higher is better for DX generally as it reduces the takeoff angle
of the main RF lobe. However, the hexbeam can be quite effective
even at modest heights.
6. What about use of steel wire or aluminum instead of copper?
A. You will need new dimensions based on conductivity of those
materials. The dimensions here are strictly for copper.
7. What about stranded wire or solid wire?
A. Either is fine.
8. What about insulated wire?
A. You can probably use it but I wouldn't depend on these
specifications which are based on bare copper wire.
9. How important is spacing on the center post?
A. Post spacing is mainly determined by the geometry of your
particular hexbeam. Try to get your wires generally parallel, level
with the ground, symmetrical, etc. Spacing can become a
problem if they are too close. In particular, it has been found by
some that if the 10 meter wires are too close to the 12 meter
wires, the two bands can interact with each other. It is hard to get
the specified 4 inch spacing between 12 and 10 meters while
keeping the 10 meter wires parallel. That's OK; just pull the wires
down the post a bit; performance will be better.
10. Should I feed the hexbeam at the top or the bottom?
A. Top feeding will provide better results overall.
11. Should I connect the bands with wire or coax?
A. Coax will provide better results. Use 50 ohm coax.
12. Do I need a balun?
A. I have done with and done without and results seem about the
same. Others feel it is important.
13. What wire lengths do I use for a hexbeam for the entire
band?
A. Just strike an average between the lower half and upper half
lengths in the table. But note the charts. The hexbeam optimal
front/back performance is pretty narrow and you will be putting
your "sweet spot" in the middle of the band. That is a good choice
if you plan to operate both CW and phone.
14. Can I use the table above for a single band hexbeam?
A. Yes, the single band lengths would be just a slight bit longer.
Add about 1/2 percent.
15. Where can I learn more about the hexbeam theory?
A. Visit the web site of Steve, G3TXQ.
Specifications and FAQ's
| Lengths of wire elements and spacing Note that driven element consists of two 1/2 sections and reflector consists of two 1/2 sections Units are Inches, wire is 16 Ga (0.051 in. dia.) |
| Positions of wires on center post These are guides only and should not be regarded with the precision of the wire lengths and the end spacers. |
| Optimized for Lower band dddddddDesignd1/2 Driver 1/2 Reflector Band Freq. wire length wire length 20 14.050 216.0 220.5 17 18.150 166.9 170.3 15 21.100 142.8 145.7 12 24.950 121.1 123.6 10 28.100 107.7 109.9 |
| dDistance above the base plate dd20 meters 42 inches dd17 meters 20 inches dd15 meters 14 inches dd12 meters 10 inches dd10 meters 6 inches |
| dddddEnd Spacing (inches) ddBand Dd Dr Dt ddd20 7.7 5.0 11.0 ddd17 6.1 4.0 8.8 ddd15 5.4 3.6 7.8 ddd12 5.4 3.6 7.8 ddd10 5.6 3.6 7.9 |
| Conversion Table for Different Wire Thickness These factors can be used to calculate new wire lengths if wire that is not 16 gauge is used |
| dWire Dia. (In.) Wire Gauge Multiply lengths by dddd0.032 20 0.996 dddd0.040 18 0.998 dddd0.051 16 1.000 dddd0.064 14 1.002 ddd 0.081 12 1.004 dddd0.102 10 1.006 |
Site publication date 12/2005
Page revision date 9/2007
Page revision date 9/2007
| Optimized for Upper band Designd1/2 Driver 1/2 Reflector Band Freq. wire length wire length 20 14.200 213.6 218.0 17 18.150 166.9 170.3 15 21.300 141.4 144.2 12 24.950 121.1 123.6 10 28.600 106.2 108.4 |
Overall data on the Hex beam by K4KIO
Freq. bands (M) 10, 12,15,17,20
Weight 20 lbs
Diameter 19.3 ft
Wind Surface Area under 5 Sq Ft
K factor 192.5 ft lbs
Freq. bands (M) 10, 12,15,17,20
Weight 20 lbs
Diameter 19.3 ft
Wind Surface Area under 5 Sq Ft
K factor 192.5 ft lbs
Hex beam by K4KIO
| dddddTable of Contents dGeneral dOverall Description dddddddBuilding it dStep 1 - Baseplate dStep 2 - Spreaders dStep 3 - Frame assembly dStep 4 - Making wire elements dStep 5 - Installing the feedlines dStep 6 - Installing the wires dStep 7 - Mast and rotator dParts for a Hexbeam dddddUnderstanding It it dSpecifications and FAQ's dPerformance and Modeling |
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