Cushcraft A50-5 Modification
By K9MU

Cushcraft A50-5 Modification
# Spacing Length - 3/4" Length - 5/8"
Ref 0.00 24 36-1/16
DE 23.0 24 32-12/16
1 54.5 24 30-12/16
2 123.0 24 30
3 187.0 24 28-1/16
Designed on YO by N0AKC - all lengths are in inches

Column 1 is the title of each element. Just like the original, there is 1 Reflector, 1 Driven Element, and 3 Directors. The gama-match does not need to be readjusted.

Column 2 is the element placement, with respect to the reflector (0.00). The reflector is placed about 1-1.5 inches from the end of boom.

Columns 3 & 4 are the element lengths. The A50-5 antenna elements are tapered, with a 3/4" tubing in the center and 5/8" element tips. To attain the proper element lengths, slide the 5/8" element ends in or out of the fixed length 3/4" tubing. (True lengths have been rounded to the nearest 1/16")

Extending the boom The original boom length is 12 feet. The above element spacing requires a boom length of 16 feet. The boom is constructed using 3 sections of 4' aluminum tubing. One of these sections needs to be replaced by an 8' section. (Ex. The original center section is 50" of 1 3/8" tubing, .058 wall thickness. Replace it with an 8' length of the same diameter tubing.)



Completed modification


A50-5S Factory


A50-5S modified on 16 foot boom


A50-5S Factory


A50-5S modified on 16 foot boom



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