OCF Masters Articles

  • My Dipole Has Gain!

    Many antenna manufacturers specify gain figures in seemingly mysterious terms that are often difficult to interpret. This article provides a framework to assist you in understanding the terms.
  • A Portable Two-Element 40-Meter Wire Beam

    We wanted an effective Field Day antenna, so we designed this portable two-element 40-meter wire beam. The design goal was for a beam with 10-foot element spacing, so the spacers could easily be carried within a minivan. Because of this limitation, the front-to-back ratio is lower than with wider spacing, and the configuration is driver and director rather than the usual driver and reflector. A further small compromise enabled a 50 Ω impedance. 
  • A New Design of a 40-6-Meter Off-Center-Fed Dipole

    You might know that a 40-meter dipole is also usable on 15, since 21 MHz is
    an odd harmonic of 7 MHz. But as W1IS and KC1DSQ explain, you’re still going
    to need a tuner for one band or the other ... unless ... unless you build their
    variation that makes the antenna resonant on five bands!
  • Baluns Basics: What’s a Balun? Why a Balun? How Do I Make a Balun?

    “Balun” (BALanced to UNbalanced) is a catch-all term for a variety of devices we use on our antenna-feed- line systems. This article will take a brief look at what they’re all about, why they’re important and how you can build your own.

  • A Simple Dual-Band Upgrade for Your 40-Meter Dipole

    During this lull in the solar cycle, 40 meters has been the best band for both local and DX contacts. Now that the sunspots are coming, other bands will soon be packed with signals as well. If you have a 40-meter dipole that's been your workhorse through the lull between Cycles 24 and 25, this will get you on 15 meters with low SWR and a minimum of effort.
  • End Effect and Harmonic Antenna Design

    This article takes you through the design of a 40 M dipole that many hams also use on the third harmonic, 15 M. In the process it starts with the speed of light and drills down to the realities affecting our antennas including, Velocity Factor, VF, and End Effect in our battle to build multi-band harmonic antennas.

  • Multiband Off-Center-Fed Dipoles for 160 & 80 Meters

    If you need a multiband wire antenna and your rig’s built-in antenna tuner can’t deal with the high SWR of a G5RV on some bands, KC1DSQ and W1IS have another suggestion to consider — an off-center-fed dipole for 80 or 160 meters that will also be usable on higher frequency bands.

  • The Design Principles of OCF Masters Antennas

    The Design Principles of OCF Masters Antennas Introduction: Off Center Fed Dipoles are popular multi-band antennas. They work pretty well, but the...
  • A Different Twist on a Dual-Band VHF/UHF J-Pole

    WA5VJB has been busy stringing antennas between satellites — in orbit — and wasn’t able to finish his planned column for this issue. Filling in for Kent this month is Robert Glorioso, W1IS, who describes how he solved some problems in making dual-band J-poles (intended mostly for field use) function well on both 2 meters and 70 centime- ters. – W2VU