WAØITP's Hentenna Antenna Page (and more)
See SVCC Antenna Info Below
Rocky ........ Coming Soon.

  All Copper Pipe Hentenna Version for 2 Meters

                     The Hentenna is a loop style antenna developed by Mr. Tadashi Okubo JH1FCZ, Mr. Someya, JE1DEU and others  in Japan in the 70's.  It was first described in the US in a Feb 1982 QST article by Koji Sugihara, JJ1UMS and Shirow Kinashita, JF6DEA/KE1EO wrote about it in the ARRL Antenna Compendium Vol 5.  The gain is approx. equal to a 3 element tribander, JH1FCZ reported 5.1 dBd in 1972, yet it is small compared to a beam. (This info was gleaned from the article on page 11, ch 12 of Simple and Fun Antennas by K8CH and N6BV)

            2M HENTENNA BUILDING AND INSTALLATION
                                                  Detailed instructions on development, construction, and installation
                                                                         of this great little antenna!

BUILDING IT

I recommend building the 1/2 " copper pipe Hentenna to these dimensions.
overall length =  40 inches
overall width = 12 3/4 inches
feed point = 7 3/16 to center line of  T connector

You'll need one 10' piece of pipe, four right angle elbows, two tee's, and two end caps from the hardware store, total cost about $12.  With the dimensions below you can just jam it all together heat and solder and it will work just fine. Or you can be a little fussier and adjust the dimensions perfectly before soldering.

Cut the pipe as follows:  (use a tubing type cutter, a hack saw’s too awkward,unless you're really good)
2 pieces 31 13/16"  for the long side pieces above the Tee's
2 pieces 6 1/16"  for the short side pieces below the Tee's
2 pieces 11 1/2"  for the two end pieces
2 pieces 5" for the feed points.

Use tin/lead rosin core solder, and shine up the ends of the pipe before soldering.  I just laid it out on the garage floor to keep it flat and applied the heat.  Be sure to wear safety goggles since concrete may "pop off" little pieces when overheated. The caps go on the end of the feed tubes and the distance between them will be around 3/4".  Solder the coax braid to one cap and the inner conductor to the other. 

INSTALLING IT

Here are several things to remember when installing this antenna.

1. Use a non-conductor for the mast, I used 1.25" schedule 40 PVC pipe.

2.  For the vertically polarized version, tape or cable tie the coax to the middle of the end piece nearest the feed point, NOT the mast.    Let it hang over the end some then attach it to the mast below the antenna, or side mount the antenna.

3.  Use non-conducting hardware to attach it to the mast.  Steel or brass bolts have a really detrimental effect on the match.  I’ve used nylon bolts, tape, cable ties, and wood dowels.

4. For a vertically polarized signal for repeaters the 40" dimension must be horizontal to the Earth. The signal is perpendicular to the axis of the feedline. See the pictures below.

5.  For a horizontally polarized signal for ssb, the 40" dimension must be vertical to the  Earth. See the pictures below.

The swr will be close to 1.0 at 146, and about 1.3 at both 144 and 148.  The 2:1 bandwidth is amazing, about 10 MHz. 

ON THE AIR TESTING RESULTS

On the air testing has been gratifying. WAØMWW and I conducted a performance test between our qth's, we're 12 miles apart, and he's in what I like to call the great Batavia RFDZ (rf dead zone). 

We used 146.52 simplex and adjusting my power levels and his antenna orientations to get a noisy signal from me.  The Hentenna proved superior to a 5/8 wave ground plane at the same height, 15' up. This was a "switch the coax" comparison so as to minimize propagation differences between tests.  We evaluated both vertical and horizontal polarization and the Hentenna signal was better in all cases, sometimes by as much as two S units.

I also can easily bring up 2 repeaters, one 30 and the other 20 miles distant off the sides of the antenna, using only 5 watts.  So the pattern isn’t too sharp for general use.
Ron, WA0MWW and I have also used a repeater that is 45 miles away with 50 watts.  A litle noisy but very Q5 copy.

I hope you have very good luck and get a lot of use from this nice antenna. It deserves much more attention than it has gotten here in the US.  Please drop me a note and let me know how it works for you.  You shouldn’t have any difficulty, but if you have any questions please let me know. We should be able to cure any problems you may have.

2M Forktenna and 440 Versions Coming Soon!

73, Terry, WAØITP 

Email Me:  Send message to wa0itp at rew2000 dot com
JR1LZK, Mr.Yutaka Tasaki (Taka)'s Hentenna Page
N4UJW's Hamuniverse.com Hentenna Page
My Hentenna Prototype on Hamuniverse.com  ... over 14000 visitors to date!                                        
 www.qsl.net      
ARRL
 
                                   Hentanna                         Hentenna
                                           Vertically Polarized Signal                               Horizontally Polarized Signal

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SVCC ... Short Vertical with a Coaxial Counterpoise

 I had been looking for a portable antenna design for some time when I spotted an interesting article in the Nov 2002 issue of CQ magazine.  My portable operating experiences to date convinced me that a half wave wire with a quarter wave counterpoise wasn't an effectve antenna system.  What I really needed was a good balcony, picnic table, or mobile antenna system.  

K4VWK's article caught my attention because he mentioned a coax counterpoise.  He expanded on a counterpoise concept suggested by DL7PE in AntennaX Magazine.  The counterpoise is made from a piece of coax in the feed line.  The center conductor conductor connects to the antenna and the shield is OPEN  at the antenna end, only the center conductor attaches to the antenna.  The other end of the counterpoise is attached to the feed line.  An RF choke is installed in the feedline between the counterpoise and the rig.  There is no radiation from the counterpoise so  it can be coiled up or strung any which way around the room , car, balcony, camper, picnic area, etc...   This thing may answer my needs for a portable antenna system.

Here's how I built the counterpoise.  I soldered the center conductor of a 1 foot piece of RG-58 to a PL-259 leaving the shield 1" short and connected to nothing!  A piece of heat shrinkable tubing provided a little stffness and protection for the center conductor.  This end is screwed onto the antenna mount.  The other end has a coupler for the rest of the counterpoise to mate with.  Using the formula in Scott's article, L=190 / f   (Mc).  I made up a jumper of RG-8X for 15M and 20M, subracting a foot for the antenna "pigtail".  The feedline choke is my old standby, 10' of 8X coiled in a 7 turn coil.

Now for the antenna.   I just had to homebrew something here so I made up a "take down"  version of a Hustler mobile mast.  It's 54" of 1/2" copper pipe, with 3/8 x 24 bolts soldered into end caps.  I put a coupler in the middle so it could be broken down to enhance portability.  Capping off the top of the mast is a Hustler 15M resonator and it's screwed into a standard whip mount by Firestick  (only $4.00).  The mount is bolted to a 2" x 6" piece of 1/8" aluminum for clamping to something.

Performance..... The whole shebang is clamped to the railing of the steps leading down to our llama barn, which makes it about 3' off the ground, between a spruce tree and the house.  My first contact was KØUSJ, Bob in Sun City AZ.  He could barely hear me and he was only about an S5 himself.  The next contact was KAØZZO, Bill in Palm Springs, CA.  He was an S7 here and I was S6-7 on my 322' dipole, and S3-S6 on the short vertical.  

The antenna performs a little better on 20m.  Changing the resonator and counterpoise resulted in a very broad banded 20M short vertical.  The swr is 1.2:1 at the top of the band, 1.0 in the middle and 1.1 att he bottom.  Not bad for an 80" long antenna!  W5KID in Baton Rouge reported S9+4 (not 40)  with the big dipole and S9 with the SVCC (short vertical coax counterpoise, my term).  W5KID is a WW2 destroyer museum ship. KL7/K1YS, North of Anchorage  reported 1 S unit difference. Both were at 14.260 Mc.  Remember it's clamped to a railing only 3' off the ground.  

So give the SVCC a try if you like to experiment,  I tried it out from the balcony of the Villa Mirage resort in Scottsdale, AZ, in March 2003, and made 29 contacts in 2 nights of operating.  States worked included HI, CA, IA, TN, TX, WA, OH and others. For what it's worth, the signal reports I received averaged 5x5.6, the ones I sent averaged 5x7.3, 1.7 S unit difference.  The highlight was working my fellow hams from Ottumwa, IA during OARC's regular monthly meeting at NØSM's QTH, using the club's call, WAØDX!  See the pictures below..

I'll be doing more comparisons both on 15 and 20M.  Stay tuned, I'll share my results if you're interested. This is  a promising portable antenna for camping, mobile, and motel operating.  If you'd like more test info, email me -  I 'll send you an Excel spreadsheet with additional data including 2 & 3 wire counterpoise comparisons...

Thanks to Scott Harwood, K4VWK for publishing the CQ article.  He also has some interesting ideas and results on short CCD antennas.  They have some real promise as portable antennas too

                                                     SVCC         SVCC              

                                                    SVCC Antenna On the Balcony In Scottsdale, AZ

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Home Station Equipment
    HF:
    Yaesu FT-840 Transceiver, Yaesu FP-1023 Switching Power Supply
    322 ' Dipole Center Fed with 450 Ohm Ladder Line, SGC 239 Autotuner
   
    Ten-Tec 580 Delta Transceiver, Ten-Tec 280 Power Supply
    MFJ-949E Antenna Tuner

    Vibroplex Paddle,  Homebrew HB9ABO CMOS Keyer

    2M:
    Yaesu FT-1500M, Kenwood FT-241, Radio Shack HTX 200,
    Antennas: Hombrew  HENTENNA, Homebrew  4 Element Vertical Collinear, 5/8 and 1/4 Wave Mg Mounts

Rocky  ........ Coming Soon.

Please check back often.  I'm just beginning to develop this web page and will include sections on Antennas, QRP rigs, and various links of interest.  The layout will change significantly.

Thanks for Stopping By and  73, Terry, WAØITP 
Email Me:  Send message to wa0itp at rew2000 dot com


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