I've have two directive systems loop yagis. The bandwidths are only slightly wider than yagis with straight elements so dimenional tolerances will be about the same. They are similar to HF quads. Each element behaves like 2 stacked dipoles with bent ends. The only unforgiving antena is a helix.
73,
John KD6OZH
----- Original Message ----- From: w7lrd@comcast.net To: "NW VHF" PNWVHFS@googlegroups.com; "AMSAT-BB" AMSAT-BB@amsat.org Sent: Thursday, January 29, 2009 18:25 UTC Subject: [amsat-bb] homebrew Loop yagi
Hello I am looking for some brain power from anyone who has built loop yagi's. I am getting my information from The ARRL Antenna book 20th edition. The book says follow exactly, however. It calls for alluminum elements 0.0325 thick, I have copper 0.025 thick. It calls for 3/4" alluminum boom I have 3/4 copper and some 1/2" stainless steel channel. The feed to the driven element is UT-14, I have a short piece with a SMA already attached, will connecting the SMA to a SMA-N adapter be acceptable? I have seen the pretty pictures of Directive Systems antennas http://www.directivesystems.com/loopyagi.htm Same idea only different parts. Are these things pretty "forgiving" or are the components critical? Also comparing the loop to a quagi the loop widths are 1/4" wide and the quagi used #18 wire, why? My intent is satellites and/or terrestial. Thanks for the bandwidth. 73 Bob W7LRD CN87 AMSAT 28498
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