From owner-qrp-l@Lehigh.EDU Fri Dec 6 10:28:38 1996 Received: from boss.cs.OhioU.Edu (root@boss.cs.ohiou.edu [132.235.1.1]) by oucsace.cs.ohiou.edu (8.7.6/8.7.1) with ESMTP id KAA14709 for ; Fri, 6 Dec 1996 10:28:33 -0500 (EST) X-Received-x: from boss.cs.OhioU.Edu (root@boss.cs.ohiou.edu [132.235.1.1]) by oucsace.cs.ohiou.edu (8.7.6/8.7.1) with ESMTP id KAA14709 for ; Fri, 6 Dec 1996 10:28:33 -0500 (EST) Received: from fidoii.CC.Lehigh.EDU (fidoii.CC.Lehigh.EDU [128.180.1.4]) by boss.cs.OhioU.Edu (8.7.6/) with ESMTP id PAA08777 for ; Fri, 6 Dec 1996 15:28:31 GMT X-Received: from fidoii.CC.Lehigh.EDU (fidoii.CC.Lehigh.EDU [128.180.1.4]) by boss.cs.OhioU.Edu (8.7.6/) with ESMTP id PAA08777 for ; Fri, 6 Dec 1996 15:28:31 GMT Received: from Lehigh.EDU ([127.0.0.1]) by fidoii.cc.lehigh.edu with SMTP id <35115-53130>; Fri, 6 Dec 1996 10:26:42 -0500 Received: from nss2.CC.Lehigh.EDU ([128.180.1.26]) by fidoii.cc.lehigh.edu with ESMTP id <34949-36492>; Fri, 6 Dec 1996 10:25:50 -0500 Received: from marceau.fm.intel.com (marceau.fm.intel.com [132.233.247.8]) by nss2.CC.Lehigh.EDU (8.8.4/8.8.4) with ESMTP id KAA206497 for ; Fri, 6 Dec 1996 10:25:40 -0500 Received: from fmmail.fm.intel.com by marceau.fm.intel.com (8.8.4/10.0i); Fri, 6 Dec 1996 15:25:39 GMT Received: (from ccmgate@localhost) by fmmail.fm.intel.com (8.7.4/8.7.3) id HAA28248 for qrp-l@lehigh.edu; Fri, 6 Dec 1996 07:23:16 -0800 (PST) Received: by ccm.fm.intel.com (ccmgate 3.2 #2) Fri, 06 Dec 96 07:23:16 PST Date: Fri, 06 Dec 96 07:19:00 PST Reply-To: Cecil_A_Moore@ccm.ch.intel.com Sender: owner-qrp-l@Lehigh.EDU Precedence: bulk From: Cecil A Moore To: "Low Power Amateur Radio Discussion" Subject: Re: Mobile Ant X-Listprocessor-Version: 8.0 -- ListProcessor(tm) by CREN Message-Id: <96Dec6.102642est.35115-53130+48@fidoii.cc.lehigh.edu> Status: RO >From: rhight@primenet.com (Roger Hightower) >Now working with a Valor 80M whip, using a DX70T and >EDX-2 autotuner, and can work all bands 10-80M. Hi Roger, when you say "work" you probably know what you mean but everyone else might not. In general, using an 80m whip with its high inductance/lossy coil on 80m is bad enough but using it on higher bands is asking for gross inefficiency. To minimize loading coil losses, the inductance of the coil should be minimized for the band in use. A magnetic mount does not have enough capacitance to the chassis on the lower bands. A grounding strap is necessary for maximum efficiency which requires exposed metal somewhere close to the mag mount. W8JI reports arcing between the mag mount and the car body on the lower bands. An autotuner is very convenient (I use one). But one must realize that an autotuner is less efficient than base-loading which is less efficient than center- loading which is less efficient than top-hat loading. 80m mobile operation is extremely inefficient even with the best antenna configuration which is a top-loaded bugcatcher mounted directly to the body on top of a large vehicle and using as large a top-hat as possible. Any compromise from this configuration decreases the radiation efficiency which is a paltry 2% with a good bugcatcher on 80m. An antenna with a coil 'Q' of 50, something like a hamstick, might have a radiation efficiency of 0.75% or less on 80m. I'm not familiar with a Valor 80m whip but I assume it is like a hamstick. 73, Cecil, W6RCA, OOTC