[HCARC] 10 meter Loop

[Gary and Arlene Johnson]

This one is sized for 6 meters, but I suspect it could be upsized for 10 meters too.  I thought of making these out of excells 1/2 inch copper water pipe, or possibly with the soft copper line that they use for refrigerator water lines or the stuff they use for copper refrigerant water lines.  So many things to think of - so much frustration not to be able to try them out.  Someday I will though.

Gary J
N5"BAA"
  ----- Original Message ----- 
  From: Bob Richie 
  To: Gary and Arlene Johnson 
  Sent: Sunday, August 12, 2012 3:15 PM
  Subject: Re: [HCARC] 10 meter Loop


  This antenna has been around for a while.  The problem is finding a place high enough to hang it around here. Some of the tall trees in the southeastern pine forests would make this a natural, along with some other loops.  If you have not been to this site http://www.hamuniverse.com/antennas.html it has a bunch of antennas and other interesting articles.

  Bob
  K5YB
  Kerrville, TX 78028


------------------------------------------------------------------------------
  From: Gary and Arlene Johnson <qltfnish at omniglobal.net>
  To: hcarc at mailman.qth.net 
  Sent: Sunday, August 12, 2012 1:54 PM
  Subject: [HCARC] 10 meter Loop


  I found the following while looking at antennas on the net.  It's called the "20db over 9 10 Meter Loop Antenna".  Diagram is on the link.

  http://9m2mgl.blogspot.com/2008/10/with-large-number-of-operators-and-wide.html

  "With the large number of operators and wide availability of inexpensive,singleband
  radios,the 10-m band could well become the hangout for local ragchewers that it was before the advent of 2-m FM,even at a low point in the solar cycle.This simple antenna provides gain over a dipole or inverted V.It is a resonant loop with a particular shape.It provides 2.1 dB gain over a dipole at low radiation angles when
  mounted well above ground. The antenna is simple to feed-no matching network is necessary.

  When fed with 50-? coax,the SWR is close to 1:1 at the design frequency,and is less than 2:1 from 28.0-28.8 MHz for an antenna resonant at 28.4 MHz.The antenna is made from #12 AWG wire (see Fig 22.80) and is fed at the center of the bottom wire.Coil the coax into a few turns near the feedpoint to provide a simple balun.A coil diameter of about a foot will work fine. You can support the antenna on a mast with spreaders made of bamboo,fiberglass, wood,PVC or other nonconducting material.You can also use aluminum tubing both for support and conductors,but you may have to readjust the antenna dimensions for resonance.

  This rectangular loop has two advantages over a resonant square loop. First,a square loop has just 1.1 dB gain over a dipole.This is a power increase of only 29%. Second,the input impedance of a square loop is about 125 ?.You must use a matching network to feed a square loop with 50-? coax.The rectangular loop achieves gain by compressing its radiation pattern in the elevation plane.The azimuth plane pattern is slightly wider than that of a dipole (it's about the same as that of an inverted V).A broad pattern is an advantage for a general-purpose,fixed antenna.Then rectangular loop provides a bidirectional gain over a broad azimuth region.

  Mount the loop as high as possible. To provide 1.7 dB gain at low angles over an
  inverted V,the top wire must be at least 30 ft high.The loop will work at lower
  heights,but its gain advantage disappears.For example, at 20 ft the loop provides
  the same gain at low angles as an inverted V.

  Sumber daripada ARRL 
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