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6m coax feed

THE COAX FED 6 METER EXTENDED DOUBLE ZEPP ZIP CORD ANTENNA

Egil, LA2PJ, Norway
Diagram below



Note - the lengths above appear to be cut for the very low end
 of the 6 meter band as used in Europe using the formulas below.
See article for suggested formulas.

http://www.hamuniverse.com/6mzepp.html


WARM UP THAT CALCULATOR!

Operating frequency 52mhz
(center of U.S. 6 meter band). Use your prefered center frequency.

We know that a full wave EDZ is actually 1.28s of a wavelength long end to end.
Using the standard formula,  (468) for a half wave, we multiply times 2 = 936 for a full wavelength.
1.28 times this  (936) = 1198 rounded off for the number to use in our formula = 1198/freqmhz

So.....1,198 divided by 52mhz = 23.03 feet for overall length.....cut in half for each leg = 11.51 feet per half or in inches = 12 X 11.51 =
138 inches rounded off per half.

Feeder Length (matching section) Calculations
Now it gets a little more difficult to calculate the feeder ladder line length. (or maybe not!)

We know by the above description that the feeder length should be about 48 degrees of a full cycle or full wavelength at 52mhz but we can't measure out 48 degrees on our tape measure so we have to convert degrees to feet and or inches.
Assuming our full wave length number that we used in the formula above (936) is correct and is equal to 360 degrees, we continue.

936 / 52mhz = 18 feet = one full wave length = 360 degrees

18 feet = 360 degrees or one full wave length.

18 / 360 degrees = .05 inches per degree.

.05 times (x) 48 degrees = 2.4 feet = 2.4 x 12 = 28.8 inches for the feeder length.

Now take the suggestion of adding 10 to 15 percent to that for tuning and we get, 28.4 X .15 = 4.26 inches added to 28.4 inches = 32.66 inches for the feeder before trimming for best SWR!
Note that we used the longer length suggestion in the formula above. (.15)

Now we know that our design must have each top half at 138 inches or 11.51 feet and our short homebrewed feeder matching transformer should be 32.66 inches before trimming.

"This example was determined by deductive reasoning using a little math with the assumption that the original design described by LA2PJ works well.
I have no reason to believe that our Ham Radio friends in Norway would have passed this design down thru the years if it was not a good design!......Please not that your installation, techniques, materials used , height above ground and other possible variables may require you to trim the antenna as needed for best performance.
As with all antenna projects, trial and error sometimes are the best teacher and the most fun!
 
Good luck on your design and we welcome feedback, tips, tricks, corrections, etc"......
I can't thank Egil enough for all his help in sharing this project with us and I am very glad his English is so much better than my NORSK! HI! .......N4UJW




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