[CQ-Contest] How to start a run

[Charlie Ocker]

A quick analysis with EZNEC v6.0+ reveals that a 125' dipole @ 14.175 
MHz yields a nice cloverleaf pattern with peaks of 3.67 dBi.  If the 
dipole is oriented N/S, the peaks are at 37, 142, 218, and 323 degrees. 
There are some deep nulls, too: -21.95 dBi E/W, and -99.99 dBi N/S.

The feedpoint impedance is 1048 + J 1421 ohms, so you'll definitely need 
open wire line to feed this antenna.

Now, over "real" ground in EZNEC (using midwest USA soil), with the 
antenna being flat @ 40' above the modeled ground, the pattern peaks are 
8.99 dBi @ 40, 140, 220, and 320 degrees.  The lobes are fatter than in 
free space: beamwidth is 34.5 degrees, with the -3dB bearings of 24.9 
and 59.4 for the 40 degree lobe.

The E/W nulls are even deeper, but the N/S ones are only down -2.35 dBi 
from the peak lobes.

The elevation plot is sorta funky looking with the peak being 2.37 dBi @ 
38 degrees.  This antenna looks like it would well in a domestic contest.

The feedpoint impedance looks better: 922.3 + J 1388 ohms.  Again, you'd 
want to use open wire line.

On a practical note, I used a 140' dipole fed with that brown close 
spaced "ladder line" stuff to a homebrew balanced L-network tuner when I 
was working in Colorado from 2002 to 2004.  The dipole was maybe 40' at 
one end, but it was over uneven ground and the other end was 25 or 30' 
high.  100w was all I ever used - NAQP's were a favorite, along with SS 
and state qso parties.  I never felt handicapped with this antenna on 
20m for domestic contests.

73 es GL!

Charlie  N9CO


On 8/21/2016 4:41 PM, Steve London wrote:
> You should be looking at the K1AR CQWW CW contest results over the past
> 10+ years.
>
> I believe that John has nothing more than a center-fed dipole, fed with
> open-wire, and using a real Johnson antenna tuner. His is up
> considerably higher - 80' or so ? No towers, no wire beams.
>
> 73,
> Steve, N2IC
>
> On 08/21/2016 02:29 PM, john at kk9a.com wrote:
>> How could this be made into an excellent 20m antenna? It will have
>> very deep
>> nulls (30dB+) and super high SWR, plus likely high feedline loss.  A 32'
>> dipole would be a better antenna.
>>
>> John KK9A
>>
>> To:    Timothy Holmes <taholmes160 at gmail.com>, cq-contest at contesting.com
>> Subject:    Re: [CQ-Contest] How to start a run
>> From:    Steve London <n2icarrl at gmail.com>
>> Reply-to:    n2ic at arrl.net
>> Date:    Sun, 21 Aug 2016 10:24:31 -0600
>>
>>>> On 08/21/2016 10:11 AM, Timothy Holmes wrote:
>>>> Hi steve
>>>> To answer your questions
>>>> My antenna was a 125 ft dipole up 40 ft
>>
>>
>> Fed and tuned how ? How high are the ends ?
>> Done right, this can be an excellent antenna. Done wrong, this makes a
>> poor
>> dummy load.
>>
>> 73,
>> Steve, N2IC
>>
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