Introduction of Hentenna

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  "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. 

 1. Easy to make

3. Good performance
  • Low angle radiation
  • 3-3.5 dBd gain
          * Total performance is equivalent to 2-3 element Yagi-uda antenna,
  • 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
Hentenna Basics
 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" Length

6m 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 easier
Assembly 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.

Hentenna Applications

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 measures
 
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 )