Dipole adventures

The 160m OCF Dipole

Desiring a multiple band wire antenna and not wanting to gather all of the piece parts. I took the easy path and purchased a 160m OCF Dipole from NI4L. I hung it in an Inverted V config with the apex hanging at approximately 70 feet and the long end (180ft) running to the south and the short end (90ft) running to the north.

I played around with various apex heights and moving the ends around with overall limited success. Referencing the screen capture below, the antenna is reading to long for 80 and 40 and to short for 20. By their very nature multi-band antennas are a compromise, reducing the length and the height while having an effect did not change the basic nature. From an SWR perspective I could optimize a band or two at the expense of others, with some bands such as 15 and 10 not getting below 3:1.

The most annoying attribute of the OCF, and this is due to its unbalanced layout is the amount of the common mode RF back down the feedline. Never a good thing and it put RF in to a lot of things in the shack.

The search was on for a more efficient solution.

While researching OCF antennas I ran across a very good article on the OCF written by Serge Stroobandt ON4AA.