Topband: Inverted L Dimensions

[Charles Moizeau]

Scott,
 
My soil in northern NJ is pretty much like yours in eastern PA.  My trees are a bit taller and I was able to get up an inverted L with a vertical run of 85'.  I also wanted to work stateside, so I arranged the antenna's configuration so that its "elbow" would lie to the southwest of the horizontal leg in order to pick up a dB or so of gain from the antenna's higher-angle, horizontally polarized radiation.
 
I still wanted to maximize the vertically polarized radiation and that meant positioning the maximum current, which occurs a quarter wavelength back from the open end of any linear antenna, at a point half way up the vertical leg.  I assumed a quarter wavelength to be 128 feet, so that meant a horizontal leg that is 85 feet long.
 
In your case, with a vertical leg of 60 feet, the horizontal leg would be 98 feet long.  The arithmetic is simple for other cases.
 
I have 22 buried radials, 65 to 120 feet long, filling an open lawn area, and they have about 4 degrees of angular spacing.  They certainly help.  I thought I could improve things by adding 16 radials, each 150-165 feet long, also inter-spaced 4 degrees, running through the wooded part of my property, but I have my doubts that the much greater work to install those radials has been worth it.  It still remains for me to disconnect all the radials an then do a comparative test of just the lawn radials vs. just the woods radials.
 
For the radials, I use DX Engineering's fine radial attachment plate and #12 or 14-gauge solid copper house wire, for which it may be cheaper to buy a 1,000-foot roll of 14-2 gauge and strip off the outer jacket, vs. six 500-foot rolls of #14.
 
73,
 
Charles, W2SH        
 
> From: kb0fhp at verizon.net
> To: topband at contesting.com
> Date: Sun, 19 Sep 2010 19:21:31 -0400
> Subject: Topband: Inverted L Dimensions
> 
> I have decided to take the plunge and put up a simple antenna for 160M.
> Several comments:
> 
> It has to be simple and not excessively expensive;
> I have limited room for antennas on my lot, and very limited room for
> radials.
> I do have multiple tall trees that I can use to hoist a wire 60 feet + in
> the air.
> My soil, if you want to call it that, is poor and rocky (typical Eastern
> PA).
> My application is casual DXing and working stateside.
> 
> Based on this, it looks like an inverted L is probably my best choice. I
> want to feed it with 50 ohm coax. Now the questions are pretty simple:
> 
> What dimensions are best - 5/16 or 1/4 wave? Both are indicated in the
> literature.
> What is simpler to match?
> Am I better off making a loaded vertical approximately 60 feet long?
> 
> I appreciate your help.
> 
> Scott aka KB0FHP
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