Ham Radio

Tuesday, October 09, 2007
Full Size Delta Loop for 20M


I came across a simple delta loop design courtesy of dxzone found on the net some time ago and have been planning to give it a go for a while.
This weekend I had a couple of hours spare, so I decided to give it a go using some 2mm multi strand wire cable, a dipole centre and a mixture of 75 ohm and 50 ohm coaxial cable.
The delta loop is supposed to be resonant on 20 meters but I found it to be a little high so at present I am tuning the Loop with my mfj-969 which copes extremely well. The resonant frequency is 13.2 MHz at the moment so the next chance I get, I shall shorten the overall length making sure that each of the three sides are still equal in length, and hopefully adjusting the antenna for maximum performance ATU free for 14.2 MHz.
I believe the miscalculation in the resonant length is probably down to the fact that my wire is covered in the plastic sleeving from the manufacturer which always effects the swr as I have noticed in past experiments with dipoles you always get slight differences with sleeved and bare wire lengths, for accurate resonant results you will benefit by using bare hard drawn copper cable without sleeving. If you are into playing around and adjustments like myself plastic sleeved cable is a superb and cheap way to get the job done.

The basic layout of the 20 Meter Delta loop, each side is 7.71 meters in length with the feed point 3/4 of the way down one side (5.78 m from the top) fed by a quarter wavelength of 75 Ohm cable (3.5m long) which is connected to a 50 Ohm cable coax into the ATU

Despite having to use the ATU at the moment I am getting some great results and signal reports with QSOs being made into Alaska, Canada, Azores, Belarus, Italy and Slovenia.
The information given at dxzone recommends that the Delta Loop should be suspended vertically with the assistance of some tall trees. Unfortunately The trees near to my QTH are not so tall, so I decided to try the Loop in the horizontal position instead and like I said so far so good.

If you are thinking about trying one of these antennas you will not be disappointed and there is more info available at

Homebrew 20 Meter Delta Loop

Good luck and let me know how you get on all comments are appreciated.

I have been comparing the Delta loop to the G5RV and Hustler 6BTV, it's early days but seems to be working well on the 20 meter band. The Delta Loop and 6BTV both terminate at a two position switch which allows me to switch between the two antennas very easily.

73 to all and thanks for visiting Ham Radio, good Dx de 2E0HTS Simon in Yorkshire, North England.
posted by Simon Davison @ 7:37 pm  
4 Comments:
  • At 2:40 pm, Blogger 2E0HTS Simon said…

    This comment has been removed by the author.

     
  • At 2:41 pm, Blogger 2E0HTS Simon said…

    I have been using the loop vertically polarized for the last two years with amazing results and very little noise.

    de Simon 2E0HTS

     
  • At 11:41 pm, Blogger Chris said…

    Simon, if I modify your antenna by placing the long axis on top and the feed point at the lower apex should I not have similar performance? Will this not result in the current being at the top of the antenna on this upper leg of the loop? The top leg will 35 feet agl. I will feed it with 450 ladder line and to a balanced tuner.

     
  • At 6:15 pm, Blogger 2E0HTS Simon said…

    Hi Chris sorry for the delay. I have found that the best configuration is when you have the most area inside the loop. it does not matter to much where the feed point is or what shape the loop is as the best results are gained with the largest inside area that you can get.

    Let us know how yours works out G L thanks and 73

    Simon

     
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