[Moon-net] More on the Dish Feed

[Pat Barthelow]

More on the dish:

See the picture: 
http://groups.msn.com/towertrailers/shoebox.msnw?action=ShowPhoto&PhotoID=65

The feed location at the vertex, (looks like a barnacle) has a circular 
couragated horn that is covered by a weather proof window, specified in the 
Docs as Mylar.  We looked at it, and indeed it WAS mylar, flakes and powder 
yesterday.  UV light and wx destroyed it.  It looks and feels very much like 
Drafting film.  about 40" square, sealed once upon a time.  Can we replace 
it with something a little more sturdy?  Say 1/8" plexiglass or lexan?   I 
think UV will destroy most anything, but 3 mil thick mylar, especially 
fast...  If the dish is used for radio Astronomy  (our hope) will thicker 
plastics have frequencies in the 1-10 ghz band that they would be 
unacceptably lossy?

73, DX, de Pat AA6EG aa6eg at hotmail.com;
Skype: Sparky599