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*Subject*: [amsat-bb] L-Band Antenna*From*: "Joel B. Black" <jbblack@xxxxxxxxxxxxxx>*Date*: Thu, 23 Nov 2000 07:17:29 -0600

I thought it would be interesting, with all the talk of S-Band, to do the calculations for an L-band helix for AO-40. I did this in an Excel spreadsheet so some of the formatting may look wrong. Also, I couldn't get Excel to calculate tangent, cosine, and square root correctly so those were done manually. Some of you "gurus" can confirm or discount my calculations. I got them from the _The_Radio_Amateur's_Satellite_Handbook_ 1st. edition, page 10-11: Free space wavelength (inches) = 11,800/f (MHz) 9.30inches (23.62 cm) Diameter = C/p 2.96inches (7.52 cm) Spacing between turns = C(tan a) 2.06inches (5.23 cm) Distance between reflector and start of first turn = S/2 1.03inches (2.62 cm) Reflector side (minimum) 0.6l 5.58inches (14.17 cm) Wire length per turn = C/cos a 9.53inches (24.21 cm) Total wire length = nL + 1/2 144.75inches (367.67 cm) Circumference: C = 1.00 Pitch angle: a = 12.5° Turns: n = 15 Antenna center frequency: 1269.250 73, Joel, K2SAT ---- Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

**Follow-Ups**:**Re: L-Band Antenna***From:*Dr. Jim Akers

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