[Antennas] matching question

[W8OKN Sean]

I will model it for you and my guess is it will perform better than most any antenna out there for 160m that most hams have.  Give me a day or two and I will model it for you.  My initial estimates are an angle of about 33 degrees at its peak gain, which isn't the greatest, for sure, but the gain may be high as well.  At 17 degrees, you'll theoretically have more than 1 dbd gain, and for 160 meters, and comapred to the antennas most hams have access to, that would be HUGE.  Rarely do hams have gain on 160 meters and most deal with whatever they can get to match on 160m.

W8OKN   
  ----- Original Message ----- 
  From: Gary K9GS 
  To: antennas at mailman.qth.net 
  Cc: Chris Boone 
  Sent: Sunday, February 15, 2009 10:27 PM
  Subject: Re: [Antennas] matching question


  Hi Chris,

  Without modeling I can guess that it would work rather poorly.  Once the length of a vertical exceeds ~5/8 wavelength many high angle lobes start to develop.  Look in any antenna book and you'll get an idea of the pattern.  I think a 3/4 wavelength antenna has a peak lobe at ~45 degrees.  a 500 ft tall antenna is pretty close to 3/4 wavelength on 160M.  Remember, AM broadcast antennas aren't designed to be good DX antennas (low radiation angle)...they are designed to put out a good ground wave signal and serve the local area.

  Probably a much better solution would be to hang antennas from the top.  Maybe a sloping dipole?

  73,

  Gary K9GS
  ++++++++++++++++++++++++++++++++++++++++++++++++
  K9GS
  Gary Schwartz           email: k9gs (at) arrl.net
  Check out K9NS on the web: http://www.k9ns.com
  Society of Midwest Contesters (SMC)     http://www.w9smc.com/
  GMDXA http://www.eng.mu.edu/gmdxa/
  ++++++++++++++++++++++++++++++++++++++++++++++++

    ----- Original Message ----- 
    From: Chris Boone 
    To: ham-antennas at yahoogroups.com ; 'Reflector Antennas Qth.net' 
    Sent: Sunday, February 15, 2009 9:08 PM
    Subject: [Antennas] matching question


    Have a chance to use a 500ft tower (Broadcast) for the 160m CQ SSB contest coming up..it does have the 120 radials under it and the station is currently running on one tower at 250watts.They have no money to finish out the matching to the new tower, etc so it is not used right now.I am curious as to what this will present on 160mtrs?? Can someone model that for me and let me know say 1800, 1900 and 2000kHz?? Plan is to put the tuner at the base and run RG 8 back to the rig..

     

    Thanks

    Chris

    WB5ITT



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