BOG antenna - WOG Wire on ground antenna



BOG/WOG antenna transformers



Single BOG, "Wire on ground" antenna /(WOG) antenna

  • The most improvement in signal strength comes from the first inch above ground. However the best antenna pattern occurs with the BOG wire against ground. Covered (insulated) wires are necessary.
  • Impedance of the termination will vary with ground conductivity, wire size, and height above ground. Recent reported termination impedances have been between 200 and 250 ohms.
  • Termination testing: Use changes of 25 ohms. Less than 25 ohm differences are difficult to detect.
  • The 200 foot WOG is not as efficient as the 440 foot up in the air Beverage, but works well, is more directional than expected, and mostly out of sight.
  • Single wire KB-1 transformer sales include a 210/235 ohm termination starting March 2014, until further notice.
  • Recent research has found that although a WOG antenna can be used over two, sometimes three bands, Excellent results occur over a very narrow band of frequencies. The best pattern comes with the best front to back, over typical earth between 180 to 200 feet. Find the frequency of maximum front to back, and adjust the WOG wire length to 160 meters.

  • Because the wire on ground is "trying" to develop signal voltage between the wire and the earth it sits upon, A good ground connection is best. In areas where the earth freezes 3 to 4 feet or in very dry soil, long ground rods make the difference

  • For best signal strength recovery use long, multiple, minimum impedance, ground rods.

  • A preamplifier in the radio room may be necessary to increase signal gain.

  • In the event ground rods cannot be used for 160 meters, use two 65 foot buried, or on ground radials at each end, connected at right angles to the WOG wire. Looking down the WOG wire forming a T. This configuration will give minimum unwanted signal/noise pickup from the radials.

  • Shorter, unbalanced radials may pick up noise or signals that have less cancellation at a transformer ground connection.





  • Common mode pick up:

  • Remove the coax from the WOG transformer and listen on the receiver to check possible coax cable pickup problems.

  • A 50 to 50 ohm isolation transformer in the WOG antenna coax cable at the shack end solved slight TV and house noise pick up.

  • The coax cable could have been buried 5-6 inches deep to reduce pick up.

  • KB-1 and KB-2 wire on ground transformers are wound with very low inter-winding coupling capacity to prevent common mode at that end of the coax.

  • A ferrite wound coil, or common mode choke could been placed at the receiver end of the coax.



  • Increased common mode decoupling of the coax cable was often accomplished by addng a coil of many coax turns, beyond the matching transformer, where the coax first met earth ground. As time passed the number of turns were reduced by adding ferrite cores.



  • Now a popular choke is constructed by winding 6-8 turns of small diameter coax in a 6 inch diameter coil held together with plastic ties. One mix 31 ferrite 'clamp on' core Amidon 2x31-1081P2, or equivalent installed over the windings.






  • BOG antennas - WOG (Wire on ground) antenna
    Two Wire / two direction configuration notes

  • Use a low impedance wire pair as ground capacitance will reduce the impedance to earth, but also the wire pair impedance.

  • Use a wire pair with a low amount of twisting to avoid signal cancellation.

  • Typical BOG wire pairs are military field telephone cable, speaker wire, and appliance zip cord.

  • Covered (insulated) wire is necessary to avoid leakage to earth.

  • Seal wire insulation ends to keep water out to avoid corrosion. Connector seal, or coax seal, and a new liquid tape work well.

  • For best signal recovery use long ground rods close to the KB-2 coax connection transformer, and KB-3 reflection transformer with short ground wires.

  • In the event that ground rods can not be used, radials as described in single wire WOG/BOG notes can be used.

  • Adjusting the antenna length for best 160 meter use can be found in the IV3PRK, Luis research notes on this WEB site.

  • Questions? email  [email protected]



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        Luis, IV3PRK, BOG antenna research at HC1PF

        Luis, IV3PRK BOG antenna modeling at HC1PF


    73
    Bruce-K1FZ
    [email protected]