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.
Comments
de Simon 2E0HTS
Let us know how yours works out G L thanks and 73
Simon
Seymour ZS1CPT
Chris my calculations show that
7.71 meters per side is too long
If you use 1005/14.200 you come
Up 2 feet shorter or 23.59’ per side
It will put you in the middle of 20m
Without a tuner.
Ian. W4IDA