PVC Pipe for Ant. constructio? - HomeBrew Forum at eHam.net

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eHam.net Forum : HomeBrew : PVC Pipe for Ant. constructio?

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PVC Pipe for Ant. constructio?	Reply
by N8SGZ on April 19, 2009	Mail this to a friend!
How can you tell if a certian brand/type of PVC Pipe has good Dielectric Characteristics? Are there markings on the pipe that can tell me this. Thanks

RE: PVC Pipe for Ant. constructio?	Reply
by WB6BYU on April 19, 2009	Mail this to a friend!
No, there are too many local manufacturers to know just what mix each one uses. The recipe varies in different parts of the country depending on how much UV resistance the pipe is expected to need. The standard test is to put a piece of PVC in the microwave oven for a minute (along with a cup of water for a load). If the pipe gets hot (or starts smoking, or bursts into flame) it isn't suitable for RF work. That said, it depends a lot on how you plan to use the pipe. I use a lot of 1/2" and 3/4" thinwall PVC pipe for VHF antennas - booms, masts, etc., without ever bothering to check the characteristics. It might be worth checking if you are planning to slip a J-pole inside, but so far I haven't run into any problems. Where it can certainly make a difference, however, is in loading coils for low band antennas, especially when it also provides mechanical support for the upper part of an antenna and/or is expected to handle appreciable power. (A large loading coil can dissipate 10% of the transmitter power in a small vertical, and the resulting heat can cause the pipe to melt even if it has good RF characteristics.) If you are using anything other than thinwall white PVC for a loading coil, it probably is worth checking. Otherwise, for mechanical supports, booms, etc., it probably doesn't make any difference. At least in my experience.

RE: PVC Pipe for Ant. constructio?	Reply
by KB1LKR on April 19, 2009	Mail this to a friend!
For outdoor radome or other low stress use, where UV/sunlight exposure occurs, you want UV resistant so look for PVC electrical conduit vs. PVC plumbing tubing, however that doesn't help w/ VHF/UHF/EHF RF issues which are likely not controlled.

RE: PVC Pipe for Ant. constructio?	Reply
by N8SGZ on April 22, 2009	Mail this to a friend!
Thanks for the replies. I will be using PVC "Type 1" (What ever that is?) for the construction of some Egg Beater Ant.s.

RE: PVC Pipe for Ant. constructio?	Reply
by KB1LKR on April 23, 2009	Mail this to a friend!
Type I PVC has less impact resistance than Type II PVC.

RE: PVC Pipe for Ant. constructio?	Reply
by N8SGZ on April 24, 2009	Mail this to a friend!
Also, the PVC Pipe that I have is made by "Charlotte Pipe" I went to thier website (www.Charlotte.com) and found no info. So, I should look for "Type 2" PVC pipe? Thanks again for your help!

RE: PVC Pipe for Ant. constructio?	Reply
by N8SGZ on April 24, 2009	Mail this to a friend!
OOOPPPS! That's WWW.Charlottepipe.com

RE: PVC Pipe for Ant. constructio?	Reply
by N8SGZ on May 4, 2009	Mail this to a friend!
I just tried the microwave test. Ran it the first time for one minute, nothing. Ran it for two minutes and the PVC just got above room temp. I say it good to go. THANKS for the help. 73's

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