Hi Jim,
You might also want to look at DX Engineering's insulated support blocks:
http://www.dxengineering.com/Products.asp?ID=24&SecID=1&DeptID=39
With these, you can stick to aluminum plates.
73 -- Larry -- W1DYJ
----- Original Message -----
From: <donovanf@starpower.net>
To: "Tower Talk List" <towertalk@contesting.com>
Cc: "Jim Brown" <jim@audiosystemsgroup.com>
Sent: Monday, September 28, 2009 7:27 AM
Subject: Re: [TowerTalk] Lexan of Plexiglass As Yagi Insulator?
> 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
>>
>>
>>_______________________________________________
>>
>>
>>
>>_______________________________________________
>>TowerTalk mailing list
>>TowerTalk@contesting.com
>>http://lists.contesting.com/mailman/listinfo/towertalk
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|