Jim,
I fabricate my element mounts from Grade LE phenolic sheeet. Mounting plates
that I fabricated 40 years ago are still as strong as ever.
http://www.mcmaster.com/#8474k172/=3sdx3a
Its available in larger and smaller sheets than shown in the specific link
above. Its easily cut on table saw or radial arm saw and easily drilled.
73
Frank
W3LPL
---- Original message ----
>Date: Mon, 28 Sep 2009 00:56:09 -0700
>From: "Jim Brown" <jim@audiosystemsgroup.com>
>Subject: [TowerTalk] Lexan of Plexiglass As Yagi Insulator?
>To: "Tower Talk List" <towertalk@contesting.com>
>
>As I proceed with building a 15M yagi, K6RM pointed me to G0KSC's OWA
>design, and K5RC noted that he likes the design. As I study G0KSC's
>website, I like it too, and note that he suggests the use of 15mm
>plexiglass as an insulator for 50 MHz and 70 MHz Yagis. One slick
>thing about the OWA design is that element lengths and spacings are
>tweaked so that it matches directly to 50 ohms. YW says 1.25 VSWR
>worst case over the band, 8.1 dBi gain over the band, >21dB F/R.
>
>My elements (from a neighboring Silent Key's boneyard) will probably
>all be 0.875-inch at the center (tapering to 5/8-inch), except that
>the driven element might be 1-inch tapering to 3/4-inch. What do you
>think? Would Plexiglass or Lexan be sufficiently robust? I'm thinking
>of drilling holes in it just like one would do with an Aluminum plate
>for two pairs of u-bolts, one to hold the element and the other to
>hold the plate to the 2-inch boom. Any other suggestions?
>
>73,
>
>Jim K9YC
>
>
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