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Re: sewer pipe

>>> Robert V Johnson <w7lrd@juno.com> 04/30/06 4:01 PM >>>
>..If I use sewer pipe (white)... as a radome over a 
>S band helix will it adversly affect the characteristics 
>of the antenna?  

I just tuned up a 2m Jpole inside a 1" PVC pipe for my
ocean going APRS buoy and it turned out to be more than
inch shorter for resonance inside the pipe than outside.

So yes, the dielectric constant of PVC is not the same as
in air, so the dimensions have to be shortened to perform
the same....

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