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[email protected] April 19th 06 07:56 PM

Carbon fiber mast - Radio transparent?
 
I have a Corsair marine F28R with a carbon fiber mast. Can I mount an
antenna inside the mast? The reason I ask is I have already lost 2
stainless whips, and the end of the mast already hangs about 6 feet
over the back of the boat when trailering, and so I'm not sure I want
to add another 4 or 8 feet to that for the radio antenna.


nimbusgb April 19th 06 08:10 PM

Carbon fiber mast - Radio transparent?
 
No, its not radio transparent. Makes a nice Faraday cage.


Larry April 20th 06 07:16 AM

Carbon fiber mast - Radio transparent?
 
" wrote in
oups.com:

I have a Corsair marine F28R with a carbon fiber mast. Can I mount an
antenna inside the mast? The reason I ask is I have already lost 2
stainless whips, and the end of the mast already hangs about 6 feet
over the back of the boat when trailering, and so I'm not sure I want
to add another 4 or 8 feet to that for the radio antenna.



Nope...Put it out of your mind. Carbon fiber is made of carbon, the stuff
used to make RESISTORS. The mast absorbs RF energy and converts it to
heat. Any energy so converted is simply lost. At least an aluminum mast
REFLECTS RF energy...(c;


GregS April 20th 06 02:06 PM

Carbon fiber mast - Radio transparent?
 
In article , Larry wrote:
" wrote in
roups.com:

I have a Corsair marine F28R with a carbon fiber mast. Can I mount an
antenna inside the mast? The reason I ask is I have already lost 2
stainless whips, and the end of the mast already hangs about 6 feet
over the back of the boat when trailering, and so I'm not sure I want
to add another 4 or 8 feet to that for the radio antenna.



Nope...Put it out of your mind. Carbon fiber is made of carbon, the stuff
used to make RESISTORS. The mast absorbs RF energy and converts it to
heat. Any energy so converted is simply lost. At least an aluminum mast
REFLECTS RF energy...(c;


I once painted black the coil of a CB antenna. Didn't work.
I found out not all blacks are the same. Some conduct electricity.

I think PVC is also a lossy material.

greg

Larry April 21st 06 12:20 AM

Carbon fiber mast - Radio transparent?
 
(GregS) wrote in news:e28114$acg$3
@usenet01.srv.cis.pitt.edu:

I once painted black the coil of a CB antenna. Didn't work.
I found out not all blacks are the same. Some conduct electricity.


If you look on the radar antenna of any Navy ship, you'll see a sign
warning the painters DO NOT PAINT. Paint is metal based, used to be lead
until very recently. Not good trying to pour millions of watts of pulsed
radar power through it, but is VERY fun to watch for the first few minutes,
as the fiberglass cover over the radar's feedhorn bursts into flames...(c;

Color matters not. Haze Grey conducts, too.


I think PVC is also a lossy material.


PVC is actually a great insulator. I make loading coils out of it for
kilowatt ham radio antennas. The Metz Manta marine VHF antenna uses PVC
pipe and end caps for its loading transformer for the end-fed 1/2 wave
whip. The transformer matches the near open end of the 1/2 wave whip to 50
ohms. Hams have been using PVC plumbing, the white PVC, for years.
Electrical PVC, the grey stuff, conduit and fittings is conductive, I
think, so wouldn't make good insulators. Plumbing PVC will withstand
tremendous RF voltages without breaking down...(c;



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