The Adventures of a Stealth Vertical Dipole

 

         At one point, I had more than 300 feet of copper wire in various antenna configurations in the sky above my residential home in Texas and it was a sad day when I took them all down.  The full wave 40 meter delta loop came down first, followed by an 80 meter bazooka. The 30 meter inverted Vee came down next followed by my all time favorite KJ5VW mini-yagi wire beam. I had taken a new job in Arizona and was moving into a condo, one with very definite, well-defined restrictions regarding outside antennas.  What’s a ham to do?  My situation was not unlike that faced by hundreds of hams every year. I hope you find my story helpful in solving your antenna restrictions.

 

         The first few months of a new job kept me too busy to even think about ham radio. By the first holiday break in December, however, I was ready to do some hammin’. I tried mounting a 20 meter hamstick on top of the aluminum carport and I made a few contacts with it, but everyone was a struggle. I tried a 20 meter dipole made of 24 gauge enamel covered wire and I would go out after dark and string it up between a two trees just outside the condo patio. The tree branches were about 12 feet off the ground and once again I made some contacts now and then, but I just wasn’t satisfied with it.  Stumbling around the dark, throwing half-filled water bottles into the tree branches and generally causing a ruckus generated some anxiety for the single professional woman living above us.  She never called the police, but asked us on several occasions whether or not we heard ‘strange’ noises outside our windows after dark. I heard nothing, of course, and claimed low battery power in my hearing aid.

 

         Finally, one afternoon I sat on my patio watching the hummingbirds wage their territorial wars over one my neighbor’s bright red feeders and a lightning bolt of an antenna idea struck. I could help those poor birds by installing another feeder. That the feeder was suspended by a 20 meter vertical dipole antenna hung in the branches of a tall pine tree was incidental to my ornithological interests.

 

Installing the Hummingbird feeder

 

         The pine tree was more than 40 feet tall, but the lowest branches were nearly 12 feet off the ground.  Getting into the tree proved to be my greatest hurdle. Condo owners rarely keep extension ladders in their storage closets and the condo handyman only worked weekdays while I was away. Not even bribery was going to solve this problem. Ham ingenuity came to the rescue in the form of a 50 foot polypropylene rope.  I  tied foot-sized loops into the rope every two feet and threw one end over the lowest branch. I put my left foot in one loop, hoisted my body off the ground and was somewhere in the midst of finding the second toe hold when I started to swing violently to and from and spinning like a top. I was only three feet off the ground. A quick call to the XYL provided a suitable anchor. She sat on the ground holding the bottom of the rope, hoping and praying that my physical agility had not totally dissipated in the 40 years since my high school athletic stardom. With the rope solidly anchored, I crawled my way up to the first horizontal branch and hoisted a now sweat-drenched body into the lowest branch of the tree. My XYL tossed a water-bottle with a line attached and I tied the light line into my belt loop and scratched and crawled my way to the 38 foot level. I secured the top of the dipole to a small branch near the top of the tree and snaked the rest of the dipole back down through branches.  The center feedpoint of the dipole used a Home Depot plastic door glide as a center insulator and I used brown Radio Shack 300 ohm twin lead as a feedline. I ran the feedline along the top of a branch, around the back of the tree, cleverly out of sight from pedestrians on the sidewalk below. The lower end of the dipole wire was about 5 feet off the ground, a perfect height for attaching a hummingbird feeder. I filled the feeder with food and attached it to the bottom of the dipole wire. It swung gently in the breeze and within three minutes a red-throated hummer claimed it and began feasting.

 

Multi-band Operation?

 

         I had no experience with using a vertical dipole and had no idea of what to expect. Like every ‘first’ contact with a new rig or a new antenna, the hands get sweaty and the heart beats faster.  I hooked the dipole to my Super Tee antenna tuner, connected the rig and held my breath to see how this antenna would load. With only modest tweaking, the SWR dropped to 1:1.1 and I was ready for a test. It was Saturday afternoon and the 20 meter band was active so I tuned up and down the band listening for a solid sounding CQ. Within moments, I heard someone calling CQ and gave him a call back.  Ever notice how the pride in your new antenna raises a notch when the ham at the other end comes back to your first call? Mine did. This antenna works and while it isn’t invisible, it is certainly well disguised.

 

         I used the stealth vertical dipole for about a year, worked several contests and was satisfied with its performance. I had an EMTECH NW20 mono-band rig and didn’t even think about trying the vertical dipole on other bands until I finished building my Elecraft K-2. Once completed, a whole new world of operation opened up to me. The rig covers 80 to 10, but what could I do with a 20 meter vertical dipole?  I really didn’t think much about it until I was in the middle of a contest and I had pretty much worked everyone I could hear on 20 meters. I moved the K2 to 15 meters and heard new and different stations operating so I tried loading the SVD on 15 meters. It tuned right up and I worked 3-4 stations with the usual 559 contest reports.  Well, it can’t hurt to try 10 meters, I thought. I switched bands to 10 meters and while there weren’t many stations coming through I thought I would see how the SVD worked.  It loaded just fine and I worked everything that I could hear. OK, there were only three stations, but I got all of them. I was tuning around 28.060 looking for other QRPer’s when I accidentally bumped the dial and ended up listening up about 2 Khz. There in the clear blue was JA2UFH calling CQ QRP TST.  No guts, no glory I thought so I returned his call. He missed part of my call so I had to do a fill, but we made a 2-way QRP contact Arizona to Japan using a 20 meter stealth vertical dipole on 10 meters. I went back to 20 meters worked a couple more stations before time ran out, but I ended the contest with a real sense of achievement.

 

About a month later, I was working a SSB contest and found I was making some contacts on 20 meters, but the competition from the QRO operators was ferocious. I moved up to 15 meters and made a couple more contacts and decided to try 10 meters . Nothing open. It was early in the day and honey-do projects got in the way of more operating, but late in the afternoon I went back to check the bands and found 10 meters open. I worked two stations, one in Florida and one in Colorado before I heard JH0HQP calling CQ repeatedly without any stations coming back.  I reached over and cranked the power to 10 watts and gave him a call.  He came back after getting part of my call and it took several tries, but he confirmed my call and my signal report so it was a valid contact.

 

The list of contacts goes on and on.  The stealth vertical dipole works well. Here are a few more shots of the antenna installation and the ham shack I used while living in a very a condo with a very restrictive homeowners bam on any kind of external antennas.

 

This is what my neighbors saw.

 

…and what the hummingbird saw.

 

The feed-line leaving the tree.

 

…and entering the shack.

 

This is the ham shack

 

Another view for the neighbors.

 

 

 

I’m not a DXer, but in addition to a few hundred hams around the US, I also worked Japan (twice), Poland, Russia, Venezuela.  Not bad for a stealth antenna, huh?