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Re: Patch logistics



Hi Joel + all

FWIW
I have been successfully using a Deli container for a helix radome for
about two years nows.
There are all sorts of questions about doing this but here is some info.
I hung this radome material out in the elements for over a year testing
the IR and temperature qualities .
A year does not tell one much .
.
It does not get brittle and break in freezing weather .
IR does not appear to bother it over a short time period ( 2 years.)
My 800 watt microwave oven will not hardly heat this unit.

The unit is a clear PETE,  density 1 Deli container.
The kind that have a hinged pop on lid .

How many times have I used the unit do to rain ?   Not very many because
2.4 gHz and rain 
do not mix well .
Does it keep the helix dry and clean ?  Yes
How long will it last , I do not really know .
Will it bother something if it deterioates in some fashion .   I do not
know.
Does it bother the reception of RF from AO-40>   Not that I can measure.

Since all can have differing environmnets I'd suggest the microwave test
for a few minutes then 
hanging one of these units in the sun , winter and summer for a while .

In my case I fastened the lid to the back of the helix reflector and pop
the radome on the lid over the helix.
The radomes pops off when needed.
That makes it replaceable if need be.     If you pick up several and
stash them.
I made sure that holes are drilled so it breathes well to prevent
condensation .
These hole are only on the bottom of the unit .
The unit should drain in the elevated and non elevated antenna
positioning.

The real question for a helix,   is this really necessary?    
The closeness of the helix matching components tends to say yes but one
helix installed 13 years ago never had one and never really needed one at
my QTH .   This helix is still in use and has no radome.    
I used the tab matching on my latest helix feed and because of the
closeness of the tab to the helix proper I desided  to use the radome.

How all of this can be applied to a patch feed leaves many more
questions.

Joe  K0VTY






On Thu, 26 Jun 2003 04:49:54 -0500 "Joel Black" <w4jbb@charter.net>
writes:
> Not that I have built a patch, but I have seen somewhere that someone 
> used
> an acrylic dome like those used on security cameras.  I just have no 
> idea
> where to find a 4" dome...  At least it's a start...
> 
> 73,
> 
> Joel B. Black, W4JBB
> w4jbb@charter.net
> 
> 
> ----- Original Message ----- 
> From: "Karl Sandstrom" <k5man@cox.net>
> To: <amsat-bb@AMSAT.Org>
> Sent: Wednesday, June 25, 2003 8:14 PM
> Subject: [amsat-bb] Patch logistics
> 
> 
> > I see that a number of folks here have built or purchased a patch 
> antenna
> of
> > one flavor or another.  I too have built a W0LMD dual band patch 
> for mode
> > L/S.  Surely most of you have insects as we do here is Louisiana.  
> A
> number
> > of these "creepy crawlers" love to built between the closely 
> spaced plates
> > of a patch.  Spiders and wasps, most notably.  I'm sure that this 
> would
> > affect the tuning and circularity of the patch.
> >
> > Is anyone doing anything to prevent these critters from setting up 
> house
> in
> > their patch?  If so, what are you doing and how is it working.
> >
> > Karl R. Sandstrom, K5MAN
> > AMSAT Area Coordinator
> > Greenwell Springs, Louisiana
> > k5man@arrl.net / k5man@amsat.org
> >
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the 
> author.
> > Not an AMSAT member? Join now to support the amateur satellite 
> program!
> > To unsubscribe, send "unsubscribe amsat-bb" to 
> Majordomo@amsat.org
> 
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the 
> author.
> Not an AMSAT member? Join now to support the amateur satellite 
> program!
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> 
> 

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