Saturday, July 31, 2010

Tower Work at KD8JHJ

Half Wave End Fed Array 40, 30, 20 meters.

Early this morning the weather conditions were ideal for tower maintenance.  Cool, high clouds and no breeze.  The first order of business was to remove an old tv antenna and 18' fiberglass vertical both of which were attached to a 10' steel mast pipe bolted to one of the tower legs with steel U-bolts.  I mounted these antennas about 15 years ago and they have seen better days.  We have had cable on and off over the years but I always left the analog over the air receiving system in place.  We used it right up until the switch over to digital tv.  We now subscribe to satellite service.

Before the removal of the old antennas I had to lower my 30 and 40 meter end fed wires and lay them safely to the side.  That's me up the tower climbing with my brand new full body harness with double hook fall arrest lanyard.  With this equipment I felt secure and safe and really enjoyed my time aloft.  The "Y" lanyard is the only way to climb.  One of the self locking hooks is always engaged to the tower at all times.

My excellent ground man Wyatt took these photos.  Not to shabby for a nine year old.

The U-bolts were completely rusted but the nuts all managed to break loose except for one in which the bolt just sheared off due to excessive force.  My only moment of trepidation was when I had all the bolts off and was supporting the mast pipe with one hand and my right foot.  Once the elements of the tv antenna were free from the top of the tower I slowly let the whole assembly tilt and as it went over I gave it a little push and it returned perfectly to earth falling right where I hoped clearing the house by five feet.

Upon lowering the 30 meter end fed I noticed that there was only a few strands of wire still connected at the ring terminal.  I snipped the wire and soldered on a fresh terminal and finished it off with several applications of heat shrink tubing to make the wire to terminal connection stiff.

The last item on my to-do list was install a new Radio Wavz End Fed Half Wave for 20 meters.  It now occupies the same spot at about 28' that the 30 meter wire used to be tied off.  Because I removed the old tv antenna I now could attach the 40 meter wire support line to the very top of the tower.  and the 30 meter wire attaches where the 40 was.  From the hardware store I picked up a 10" eye bolt and secured the 40 meter support line to it and then simply slid the eye bolt into the steel tube at the top of the tower. 

I now have three half wave antennas resonant in the lower end of each of my favorite ham bands.  All wires checked out satisfactory using my antenna analyzer especially 40 meters which showed a perfect 1:1 swr for about 100 KHz. 

Here's the birds eye view!


  1. Wow, that looks like a lot of trips up and down to detach and reattach your antennas. Nice work!

    Where do you connect the other end of the End Feds? To a tree?

    I had to read up on EF antennas because I knew nothing about them. If I grasp the information I read correctly, you have 3 EF antennas set up. The lengths of which should be at least a quarter of the band on which you want to operate (20 meters to operate on the 80 meter band)? The article I read talks about configuring your ground equipment as well, to optimize your antenna set up. There's a lot to this! Here's a link to what I read:

    Very interesting stuff; enjoying the blog!

  2. Thanks for comments.
    Right 3 antennas:
    Top position is for 7 MHz wire= 66 feet
    middle position is for 10 MHz wire= 46 feet
    bottom position is for 14 MHz wire= 33 feet

    I know it gets confusing. We refer to the bands by their wavelength, a 7 MHz wave is 40 meters long. Remember your CB radio? 27 MHz or 11 meter. Very near CB is the 10 meter ham band covering from 28.000 MHz to 29 MHz. and to get an idea of where you are in the radio spectrum remember FM broadcast radio 88 MHz to 108 MHz or AM down at the other end- 1 MHz to 1.8 MHz. (160 meter)

    And it doesn't help we do things in inches and feet and yards.

    Thats what is cool about amateur radio. Our allocation allows us to experiment all over the radio spectrum from lower frequencies all the way to microwaves. Waves of different frequencies act different once let loose in the atmosphere. FM radio- line of sight only about 50 or 60 miles. Short wave ham radio (my setup) radio waves "skip" off the ionosphere and follow the curve of the Earth.

    Your Right interesting stuff!

  3. Yes, the Dacron support lines at the far end of the antennas tie off to a tree branch about 70 feet from the tower. This span is the longest distance possible on my piece of property. The Power lines and service drops are at the front and opposite side of the house so can't go into that area anyways. Part of the challenge of ham radio is working with what you have. There is always a way to do something.

  4. That explains a lot. So, is there anyway to use a CB radio to boost up one meter and talk on the HAM band?

    I am very seriously considering picking up a CB base unit to start playing around with. I know it's pretty low frequency but it would be a cheap way to get back on the air. In a city with more than 8 million people, I'm bound to find some chatter.

    I have a lot to learn about HAM but I may pursue it more this winter. My interest is officially piqued.

  5. This article ( just answered my question about using a CB radio to talk on the 10m band. Kind of a stupid question in retrospect lol. Now I'm looking at the cost of a 10m HAM system, and local courses for getting licensed. My wife will be thrilled...

  6. Mike
    Take your time. I spent 3 months the summer of 08 studying the Tech and General class courses then took them in the fall at the same time. Depending on your study habbits probably take alot less than that.

    The Web is a great source of information concerning ham radio. Sites like and eham are huge and also offer practice tests made up from the actual question pools. So you can take the test to check your proggress and you will know when your ready to take the real one.

    Another thing we have not talked about as it's not currently an interest of mine in VHF/UHF. Most all hams start out with a handheld/ mobile and talk on local repeaters. This is very similar to the way cb used to be back in the day. In the NYC area there are probably many repeaters and loads of action on 2M and 440 MHz. These ham bands are close to the public service freqs and business bands like the taxi cab drivers use. The first licence (Technician) allows use on all the VHF/UHF and a good portion of 10 meters. Because of your experience on the citizens band you be right at home working the local repeaters.

    So anyway What I am saying is do some reading and try to figure out which direction you might want to go. Like you said there is lots to ham radio. Even the old timers say they are always learning somthing new.

    Sorry for the delay in my responses. Computer is down at home so I have to cross town to my office to get online.

  7. No need to hurry on your replies.

    I'm reading a lot of material about HAM radio. Thanks for the links to QRZ and EHAM. I went and tried my hand at a Technician exam at QRZ just to see what kind of material is covered. It's all very interesting. I went to college to learn how to fix airplanes (I have a degree in Aviation Maintenance Technology and my FAA Airframe & Powerplant License) and the questions reminded me a lot of the comm systems I had studied but have since forgotten about. Working on planes I never had to do much work in the cockpits, and all instrument work was simply remove and replace.

    I'm very interested in getting my license and using the 10m band for some DX communication and am interested in learning Morse code. From what I have read, Morse code enables you to make contacts over greater distances than voice, as it is easier to decipher than voice on a weak signal. That's what's exciting to me; contacting someone on the other side of the globe. Perhaps my sights are set a little too high right now though. I will look into VHF/UHF as it could be a good starting point for me.

    In my research I'll surely have a more questions for you. When the time comes I'll ask if I can email you as opposed to filling your blog with correspondence. Thanks for your help. Your blog holds a wealth of fascinating info and as I read through your older posts I research areas I don't understand. When I finally understand it, it becomes even more interesting.

  8. Great, I look forward to helping out however I can. Let me know.