Return-Path: Received: from marvkaye.olsusa.com ([205.245.9.200]) by truman.olsusa.com (Post.Office MTA v3.1.2 release (PO203-101c) ID# 0-44819U2500L250S0) with SMTP id AAA8933 for ; Sat, 10 Oct 1998 21:39:17 -0400 Message-Id: <3.0.3.32.19981010213844.00717e08@olsusa.com> Date: Sat, 10 Oct 1998 21:38:44 -0400 To: lancair.list@olsusa.com From: "Angier M. Ames" (by way of Marvin Kaye ) Subject: Re: Marker Beacon Antenna X-Mailing-List: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Since I'm bored and waiting for epoxy to cure, I thought I'd make up and install a Marker Beacon antenna in my 360 today by strippng RG142 center conductor to the proper length, but what might that be and is this a good idea??.(It's actually going to be a 360 cause in a moment of extreme weakness, I sent off a deposit to Lancair for a new motor). Anyway, if I understand the theory correctly, (speed of light/75MHz) yields a wavelength of 4 meters*(39.37in) for an antenna length of 157.48 inches.Hmmm, almost as long as my plane.A half-wave antenna would be 78.74 inches but with my center conductor being only .0375, I don't get much help from a Length/Diameter Ratio Shortening Factor of about .978 >From a practical experience point of view from those of you who have done it, What is a reasonable alternative? Coax soldered to an adhesive backed copper strip placed along the bottom fuselage centerline? But then it is close to the elevator push rod. The AeroElectric Connection states that "proximity to other conductors adds capacitance to the resonance equation causing the resonant frequency to shift lower, requiring the antenna to be further shortened.... Help! What's a poor bugger to do? Angier Ames