Extending The Bandwidth of 80 Meter Dipoles

The 80M band covers 3.500 MHz to 4.000 MHz.  This bandwidth relative to the center frequency is very large, and this makes it very difficult for an antenna to cover the whole band with acceptable SWR.  Most of my casual operating on 80 is on the low end, chasing DX on CW. For this I use my second tower which is shunt fed as a vertical. A relatively low dipole is a more effective antenna for domestic contests.  The problem is that a dipole does not cover both the phone and CW segments well.  My solution is to add "tails" to the dipole when I want to operate in domestic CW contests.

The tails lower the resonate frequency of the dipole so it is matched at the CW end of the band. The first step is to tune the dipole to the center frequency of the phone band.  I then soldered ring terminals at each end of the dipole.  The next step is to make up the wire tails.

Start with wires about 5' long. Put a ring terminal on one end ofthe wires. Connect the two tails to the dipole ends with stainless steel screws and nuts. Tune the antenna for the CW portion of the band by trimming the ends of the tails.  

Just lower the dipole ends and add or remove the tails when you want to switch modes. This takes about 10 minutes, but I only do it when I want to do a contest. Since the shunt fed tower is tuned for the CW end of the band, I usually leave the tails off so I have something that can be used on phone between contests.

© 2009 - 2014 Gary C. Sutcliffe

  

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