On Tue, 26 Feb 2008 23:02:37 -0800 (PST), K7ITM wrote:
Let's see...500MHz to 1.05*500MHz = 525MHz; boom long enough to get me
about 10dBi over that range. I'll scale it to my particular
frequencies of interest, so any other ~5% bandwidth in that general
vicinity of frequencies would be fine too.

Cheers,
Tom

This is a Log Periodic design. Double booms, 1 inch square, spaced
1.4 inches c-c. Boom length ~55 inches.

Sweep for 500-525 MHz
Free Space Gain - 11.6 - 12.6 dBi
vswr 1.7:1.0

X is the position of the element along the boom.
Y is the length of each "half-element". With a double boom design,
one half of the dipole is mounted to one boom and the other half is
mounted to the other boom.

Coax attached to the front of the booms, shield to one, center to the
other. Do not run coax between the booms.

Booms can be electrically shorted to each other behind element # 1.


You don't have to be this accurate, my calculator defaults to 5
places. Simply convert lenghts to the nearest mm is the easiest.

x y
End 0
1 2, 5.78592,
2 6.16586, 5.61234,
3 10.2067, 5.44397,
4 14.1264, 5.28065,
5 17.9285, 5.12223,
6 21.6165, 4.96857,
7 25.1939, 4.81951,
8 28.6639, 4.67492,
9 32.0299, 4.53468,
10 35.2948 , 4.39864,
11 38.4618, 4.26668,
12 41.5338, 4.13868,
13 44.5137 ,4.01452
14 47.4041 , 3.89408,
15 50.2079, 3.77726,
16 52.9275, 3.66394,
End 54.9275

have fun