Modification of the KLM 7LP antenna to a six element yagi by Mike - K6MYC:
Boom spacing from reflector end of boom:
1/2-inch diameter elements (Half Length):
REF = 55.875
DE =51.25 (start long and trim to tune)
DR1 = 50/813
DR2 = 49.750
DR3 = 49.625
DR4 = 50.062
Hairpin and balun attach to the DE. Hairpin phasing line is 20-inch long by 1/2 inch
wide aluminum strap with holes drilled every 1/2 inch for about 4-inches from each end of strap.
At 4-1/2 inch from end of strap twist strap 90 degree so strap can be bent into U-shape.
Use holes to adjust length of strap for tuning (roughly 3-inch wide by 5.5 inch long).
Antenna dimentions are for 50.175 MHz with SWR 1.05:1.
SWR at 50-MHz is about 1.35:1 and 1.69:1 at 50.400 MHz.
Mike estimates gain at 13.09 dB and F/B = 21 dB.
Return to Home