my hentenna K7TJO

You've heard of the J-pole, See the Ski-pole for 2 meters and 6 meters!

The attachment of the two matching feed arms to the main body as seen in the picture, is a friction attachment with three parts:
1. I used a grinder to make the end of the short tube fit nearly flush against the long tube.
2. I drilled a hole through the pipe and fed a steel wire through it. (Rusty in the picture)
3. I used a hose clamp fully undone and fed behind the wire then around the long tube.
My guess is that the weakest part of the current configuration is actually the steel wire, which I will replace with something less easily corroded.
It hasn't been soldered.. I have held it toghther with aluminum tape.
There is a solid nylon "plug" inserted into the inner ends of the feedpoint.
The feed-line is only taped at the moment, but it works great. I wouldn't mount it permanently like this though.
I started one inch larger and cut to here. It might be even better if cut further.
I envision a tent-pole style interior elastic cord to hold this all together and still allow it to be broken down to a more easily carried package.
My next one will be wire again, but with kite-parts as the spreaders. I'm looking for an easy corner fitting. At the moment, arrow knocks look like the best candidate.
I am also going to make a wire one for 440mhz.
I'm contemplating a Reflector to increase the gain and change the bi-directional peanut pattern to uni-directional pear. I know it should be "slightly" larger, but I don't know how much. ( http://www.signalengineering.com/ultimate/cubical_quad.html says 10% increase in circumference)
I also have a recently discarded TV antenna that I am going to turn into some sort of Yagi. I've looked at several different plans. Haven't decided yet. Opinions welcome.

Inches and meters Javascript Wavelength Calculator == includes provision for calculating electrical wavelength given cable type., Wire diameter calculator, and generic feet and inches to metric. (not just decimal feet.)

click here

ﾚﾂﾄﾄﾄﾄｿﾀﾁﾄﾄﾄﾄﾙ Hentenna Adjust from 1/10th to In this position, radiation is vertically polarized ﾚﾄﾄﾄﾄﾄ1/6 WLﾄﾄﾄｿﾚﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ1/2 WL overallﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿﾚﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾜﾛﾜﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿｿｳ for best ｳﾛ The three verticals are the radiators. ｳｳｳ SWR ｳﾛ The Hentenna is a special case of a class ｳｳｳｳ Feed Point center ﾛ of antennas known as ADR Asymetric Double ｳｳﾍｳﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾛ Rectangles. See ｳ1/6 wl ｳfeed line out ｳﾛ Dan Handelsman, N2DT ｳｳｳ of end ｳﾛ QEX, Jan/Feb 2002 pp 12-22 ｳｳｳｳﾛｳｳﾀ-ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾛﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ-ﾄﾙﾙﾛ Generalizations: Larger diameter gives ﾛ greater bandwith. Radiation is directional ﾛ perpendicualr to the plane of the rectangle ﾛ A reflector of the same shape but slightly ﾛ Non-conducting mast -- no metal contact to loop larger can improve both the forward gain ﾛ and the front to back ratio. If you need ﾛ omnidirectional coverage, this is not the best antenna, but if you can use direction, this is an easy to make antenna with much less fuss than many others of similar gain. It is very wide bandwidth and forgiving of small differences in element size. By moving the distance of the feed vertical toward or away from the end of the loop, SWR can be adjusted. ﾚﾂﾄﾄﾄﾄｿﾀﾁﾄﾄﾄﾄﾙ Hentenna Adjust from 1/10th to In this position, radiation is vertically polarized ﾚﾄﾄﾄﾄﾄ1/6 WLﾄﾄﾄｿﾚﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ1/2 WL overallﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿﾉﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾋﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾜﾛﾜﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍｻｿｺ for best ｺﾛ The three verticals are the radiators. ｺｳｺ SWR ｺﾛ The Hentenna is a special case of a class ｺｳｺｺ Feed Point center ﾛ of antennas known as ADR Asymetric Double ｺｳﾍｺﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾛ Rectangles. See ｺ1/6 wl ｺfeed line out ｺﾛ Dan Handelsman, N2DT ｺｳｺ of end ｺﾛ QEX, Jan/Feb 2002pp 12-22 ｺｳｺｺﾛｺｳﾈﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾊﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾛﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍﾍｼﾙﾛ Generalizations: Larger diameter gives ﾛ greater bandwith. Radiation is directional ﾛ perpendicualr to the plane of the rectangle ﾛ A reflector of the same shape but slightly ﾛ Non-conducting mast -- no metal contact to loop larger can improve both the forward gain ﾛ and the front to back ratio. If you need ﾛ omnidirectional coverage, this is not the best antenna, but if you can use direction, this is an easy to make antenna with much less fuss than many others of similar gain. It is very wide bandwidth and forgiving of small differences in element size. By moving the distance of the feed vertical toward or away from the end of the loop, SWR can be adjusted. Hentenna Adjust from 1/10th to In this position, radiation is vertically polarized +-----1/6 WL--+ +-----------------------------------1/2 WL overall--------------------------------------+ +-------------+----------------------------+--------------------------------------------+ + | for best | | The three verticals are the radiators. | | | SWR | | The Hentenna is a special case of a class | | | | Feed Point center | of antennas known as ADR Asymetric Double | | =|============= | Rectangles. See |1/6 wl |feed line out| | Dan Handelsman, N2DT | | | of end | | QEX, Jan/Feb 2002 pp 12-22 | | | | | | | +-------------+----------------------------+--------------------------------------------+ + | Generalizations: Larger diameter gives | greater bandwith. Radiation is directional| perpendicualr to the plane of the rectangle| A reflector of the same shape but slightly | Non-conducting mast -- no metal contact to loop larger can improve both the forward gain | and the front to back ratio. If you need | omnidirectional coverage, this is not the best antenna, but if you can use direction, this is an easy to make antenna with much less fuss than many others of similar gain. It is very wide bandwidth and forgiving of small differences in element size. By moving the distance of the feed vertical toward or away from the end of the loop, SWR can be adjusted.

HEN is a japanese word that means something like amazing , marvelous or even magic !!! Well the HENTENNA is a rather easy to design and build... Its construction is rather simple, and it is BI-DIRECTIONAL antenna system, with a pattern that has two broad lobes, and two sharp nulls... The HENTENNA also has GAIN over a dipole, not much, but nevertheless some gain...
Ready to copy, here we go with the data... Just draw a rectangle... the geometrical figure with two long and two short parallel sides...
The long sides of the rectangle that form the HENTENNA are exactly one half wavelength long...
and the two short sides are one sixth of a wavelength long.
So we have a rectangle that is 0.5 wavelengths on the long sides and 0.16 wavelengths on the short sides. The antenna is fed very easily, by placing the feedpoints 0.16 wavelength or 1/6 of a wavelength from one end of the long sides. Almost perfect one to one voltage standing wave ratio is achieved by just slightly moving the feedpoints up and down the long sides of the antenna. You can make a nice HENTENNA for the two meter amateur band, using solid copper wire, with no 10 or no 8 bare copper wire as the ideal ones to make the antenna.
The construction is as easy as one can think, and the antenna requires just one well done connection to complete the rectangular loop.
Ideally you should solder the wires to complete the loop, something you will also need to do to the coaxial cable that connects the antenna to your receiver or transceiver.
For the two meter amateur band, the most popular ham band worldwide, the HENTENNA has long sides of 98 centimeters, and the short sides are just 32 centimeters long.
The feedpoints are located exactly 32 centimeters from one end of the antenna, and you may need to move the feedpoints slightly up and down to achieve a perfect match.
One easy way of holding the HENTENNA is by using a length of CPVC pipe, the one used by plumbers nowadays....
A two meter long CPVC pipe of about one inch diameter will serve both as the support for the HENTENNA and also as a short mast.
You can install a HENTENNA almost anywhere, and for the two meter band application don't forget to place the antenna in the direction of your favorite repeater or area of coverage.

Continued on 5-6 april
Now item four: A note about the HENTENNA that was pending from a recent show... The HENTENNA , when used for horizontal polarization must be installed with the long sides of it in a vertical position !!! Surprising as it may seem , that's the way to do it, and when using the HENTENNA on 2 meters FM, do remember to install it so that the long sides of the rectangle are parallel to the ground... It is something that is not so obvious, and that has caused that some builders of the HENTENNA wondered what was happening , as the antenna did not seemed to work properly ... and they thought that the antenna was not a good design... BUT, after twisting the position of the antenna all around, the found out that it works really very well !!! So , again, be aware that contrary to what you may think , the HENTENNA is used horizontally for vertical polarization, that is , you place the long sides of the HENTENNA parallel to the ground when working two meters FM that is vertically polarized !!!

			length		width	matching end loop	major diagonal spreader	length		width	matching end loop	major diagonal spreader	circum- frence	circum- frence
mhz	λ meter	λ inch	1/2 λ inches	1/4 λ inches	1/6 λ inches	1/10 λ inches	inches	1/2 λ cm	1/4 λ cm	1/6λ cm	1/10 λ cm	cm	cm	in
144.00	2.08	81.75	40.87	20.44	13.62	8.17	43.08	103.82	51.91	34.61	20.76	109.44	276.85	109.00
144.50	2.07	81.46	40.73	20.37	13.58	8.15	42.94	103.46	51.73	34.49	20.69	109.06	275.89	108.62
145.00	2.06	81.18	40.59	20.30	13.53	8.12	42.79	103.10	51.55	34.37	20.62	108.68	274.94	108.25
145.50	2.05	80.90	40.45	20.23	13.48	8.09	42.64	102.75	51.37	34.25	20.55	108.31	274.00	107.87
146.00	2.05	80.63	40.31	20.16	13.44	8.06	42.49	102.40	51.20	34.13	20.48	107.94	273.06	107.50
146.00	1.97	80.63	38.70	19.35	12.90	7.74	40.79	98.30	49.15	32.77	19.66	103.62	273.06	107.50
146.50	2.04	80.35	40.18	20.09	13.39	8.04	42.35	102.05	51.02	34.02	20.41	107.57	272.13	107.14
147.00	2.03	80.08	40.04	20.02	13.35	8.01	42.21	101.70	50.85	33.90	20.34	107.20	271.20	106.77
147.50	2.03	79.81	39.90	19.95	13.30	7.98	42.06	101.36	50.68	33.79	20.27	106.84	270.28	106.41
148.00	2.02	79.54	39.77	19.88	13.26	7.95	41.92	101.01	50.51	33.67	20.20	106.48	269.37	106.05
148.50	2.01	79.27	39.64	19.82	13.21	7.93	41.78	100.67	50.34	33.56	20.13	106.12	268.46	105.69
149.00	2.01	79.00	39.50	19.75	13.17	7.90	41.64	100.34	50.17	33.45	20.07	105.76	267.56	105.34

K7TJO My first copper pipe hentenna. A 4/3 λ loop with a matching section.

You've heard of the J-pole, See the Ski-pole for 2 meters and 6 meters!

Notes below From: http://www.qsl.net/wa0itp/

WA0ITP's later recommended measurements.