Random Length Wire Antenna

I have been wanting to experiment with a random length wire antenna for some time.

My primary reason for trying one is to see if I can get a better signal in and out, on multiple bands, versus the fan dipole that I have in the attic. Furthermore, I think I can sneak one outside without the neighbors or HOA complaining.

I have learned that not all lengths of wire work well (for the bands you want to work). Apparently the lengths that are a half wave on any frequency (or any multiple of a half wave length) don’t work well as they will give you very high SWR. I am not sure why…but I trust those who may be in the know.

Mike, AB3AP posted a page which is a great resource:
http://udel.edu/~mm/ham/randomWire/

Here are his calculated lengths to avoid (shown as areas in colors…white gaps or areas are lengths to use).

20130510-071129.jpg

20130510-065726.jpg

Mike’s graph goes out 535 ft…but I’ve cropped it here.

For those of us wanting to get moving quickly on this will notice that Mike wrote that a standard recommendation (see QST, March 1936, p. 32, “An Unorthodox Antenna”) is an 84′ long end fed and a 17′ long counterpoise (6.5′ for 20m). I may give this length a try.

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One thought on “Random Length Wire Antenna

  1. Pingback: Random Wire Antenna with Ground Radial System (inverted “L”) | K4MTX

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