[TowerTalk] 160-m Inverted L or Sloper?

Dennis OConnor ad4hk2004 at yahoo.com
Tue Nov 15 10:50:22 EST 2005

 I have more space than most for antennas.. I  am tinkering with 80 meter vertical arrays right now...  My  reference antenna, a quarter wave vertical, is 600+ feet out front of  the nearest array, and Eznec still shows significant interaction with a  change of >3dB in the FB ratio and distortion of the forward  pattern... Nothing that I am likely to hear on the air, but it is  there... I am adding a relay to open the reference vertical when using  the south firing array...
  Interestingly, the two directional vertical arrays are mounted 250 feet  apart (~1 wl) with the reflectors facing each other..  Eznec shows  minimal interaction with only 0.02 amps of induced current in the'  idling array' (worst case) for 1 amp in the active array and minimal  pattern changes, not enough to make me install relays...
  So, other antennas in the near (and not so near) field can have  significant effects on the expected pattern...  When I move the  reference antenna towards the driven array (via Eznec) the interaction  goes up exponentially and at a quarter wave of spacing the directional  array pattern has become garbage...
  denny - k8do

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