Introduction of Hentenna
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1. Easy to make
"Hentenna" was developed by Japanese 6m Hams (JE1DEU / JH1FCZ/ JH1YST members) in 1970s.Finally they got new antenna with good performance, however, it was difficult to explain why the performance is so good, or how it work basically at that time. So they named it Hentenna, because, "Hen" means "strange" in Japanese.
Anyway, the antenna has good performance and many advantages, it was becoming very popular in Japan. Many of JA stations make it and enjoy their Ham life at Home or in a field. Some Japanese 6m beacon stations are using Hentenna based antenna actually.
I got more than 400 hits using keyword by "hentenna" on Japanese search engine, but, not many Hentenna information is available in English. I am very happy if we could share the good antenna with many people on the web.
- It is possible to adjust impedance and SWR perfectly, This means, not so sensitive to make.
- No special parts are required. You can use any electric conductor for making the main rectangle
- Easy adjustment
2. Easy to build up
- If you use thin aluminum pipe and thin wire, you can make this antenna for 6m less than 500g
- This means, it is easy to put it higher position in the air. You can also use light mast for it.
- As this vertically long antenna, it is easy to install the antenna on a veranda or small space.
- Vertical long physically but mainly Horizontal radiation: This is one of the reason this antenna is "Hen".3. Good performance
* Total performance is equivalent to 2-3 element Yagi-uda antenna,
- Low angle radiation
- 3-3.5 dBd gain
- Wide band width
(MMANA Antenna Simulation Software by JE3HHT)How to make Hentenna
General Formula Length For 6m W =1/6 WL 1m or 3.28 feet H = 1/2 WL 3m or 11.46 feet S : about 1/10 WL
Need to adjust (Points "a" and"b")
0.6m or 1.97 feet F : Feeding point 50 or 75 Ohm
Feed here by coax cable direct (Also balan feed is possible)
WL : Wave Length
- Above formula is applicable from HF to UHF
- W also applicable from 1/10 - 1/5 WL
W:1/6 is the standard
1. Basically 1 WL Loop antenna
2. L1 works as 1 loop antenna
3. L2 works as matching section
4. Vertical long rectangle make more gain than ordinal square loop and less impedance. L2 helps the matching and low angle radiation.
5. 3D pattern is like shell of peanut
How to Adjust
1. Move "a" and "b" point to adjust
S1 >S Matching Frequency UP
S1 <S Frq DOWN )
2. Even matching point is fixed, SWR may higher than 1:1.5, Try to move points "a": S1 + little / "b": S1 - little to find best position for SWR
* S1: Adjusted "S" Length6m Hentenna parts example
1. Horizontal element 12mm diameter Aluminum pipe 1000mm x 2 2. Vertical element 2mm diameter Stainless steel wire 3000mm x2 3. Feeding element 2mm diameter Copper wire 480 mm x2 4. Bite clip for "a" and "b" points To make adjustment easierAssembly work
Make rectangular using parts 1, 2 and appropriate bolts, press connection terminals.
Make feeder elements using 3 and 4 and coax cable.
(You can use coax connector at "F" point)
Adjust Frequency and impedance moving point "a" and "b"
Caution : If you use electric conduct materials for the antenna mast, it may effect badly to the antenna. So, it is better to use none electric conduct mast, like FRP, or isolate joint points from the electric conduct mast. I always use FRP fishing pole refer to the picture on the top.
3 element Hentenna for 6m
Front gain : 8.56dBd
F/B ratio : 20.0
Radiation angle : Lower than topical 6 element Yagi.
* This antenna performance is similar to 5.2m boom 6 element Yagi.
* Check the pictures below for more information.
Director Radiator Reflector Height (H) 2.94m 2.99m 3.06m Width (W) 1.00 m 1.00m 1.00m Position of Loop separator (S) 0.67m 0.68m 0.69m Element Position D-Ra: 1.11m - Ra-R: 1.57m
(MMANA Antenna Simulation Software by JE3HHT)
Hentenna has 3 important measures. They are H: height, W: width and S: (See right picture for the reference).
Following list is these standard measures for each armature bands.
For the adjustment, please refer to top page of Hentenna but the only thing you have to do is adjusting "S" measure moving a,b points.
80m 40m 30m 20m 17m 15m 12m 10m 6m 2m Freq.(MHz) 3.550 7.050 10.10 14.20 18.15 21.25 24.95 28.50 50.20 144.2 Wavelength (m) 84.51 42.55 29.70 21.13 16.53 14.12 12.02 10.53 5.976 2.083 Height: H (m) 44.25 21.28 14.85 10.56 8.26 7.06 6.01 5.26 3.00 1.04 Width : W (m) 14.08 7.09 4.95 3.52 2.75 2.35 2.00 1.75 1.00 0.35 Position of Loop separator : S (m) 8.45 4.26 2.97 2.11 1.65 1.41 1.20 1.05 0.60 0.21 Sample Picture of Hentenna for 15m band by ON6TZ
( H:6.72 m / W : 2.24m / S : 1.34m )