[amsat-bb] Re: brain picking time

Greg D. ko6th_greg at hotmail.com
Mon Aug 4 19:47:17 PDT 2008

Hi Bob,

Interesting idea.  I think that the foam insulation, even though it doesn't absorb microwave energy, will alter the electrical characteristics of the helix.  So, the dimensions - the diameter and/or the turn pitch - will need to be changed.  It certainly would make for a durable antenna, however.

Good luck,

Greg  KO6TH

> From: w7lrd at comcast.net
> To: AMSAT-BB at amsat.org
> Date: Tue, 5 Aug 2008 00:35:30 +0000
> Subject: [amsat-bb]  brain picking time
> Hello all
> I have a couple of questions of some things I am working on-
> Has anyone used that expanding foam that you use for filling holes and gaps in walls etc.  I am trying to use it for helix support inside some PVC pipe for a 2.4Ghz 6 turn helix.  Once expanded it provides a rigid support for the coil.  It stays cool in a microwave oven.  I have no idea what if any the properties are regarding microwave applications.  As with most of my efforts I just build and try.
> Next question- which probably would be more aimed at a EME bb.  I have a 12 foot TVRO I am building a patch feed for 1296, and feed it through 50 feet of LMR400 to my IC-1271A.  I want to see if I am able to "hear" EME signals.  Of course if I am able to, you can guess what my next effort will be.  This will be a cheapie effort as I am only using stuff I already have.  I do have a KJ6KO L band  70 watt amp.
> 73 Bob W7LRD
> Seattle
> --
> "if this were easy, everyone would be doing it"
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