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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