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Author Topic: Cable access to outdoors  (Read 1746 times)
KO1D
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Posts: 387




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« on: November 15, 2011, 06:24:02 AM »

All:

A wonderful thing when one's father-in-law suggests drilling the hole in the house....the wife says yes great idea! So no a quick question. I am going to put in a hole that can double as a dryer vent in the future (3-4" hole) should we sell the house. I have V/UHF antennas on the roof, HF coax and twin lead fed antennas going up there as well as else where, and I have a station ground to run to the 8ft ground rod and house ground. The caveat is I need to make this look nice.

So we have two options on the table. Since I have aluminum siding I can use either 3-4" diameter PVC and run that to the roof and have an access for the station ground at the bottom. OR I can use a piece of siding used to cover the air conditioner lines to the attic. This seems to be a U shape box that has screws holding it up.

My initial gut reaction is to use the PVC since it will give some insulation. I am not one to run a lot of power and the open wife will probably never have more than 200w on it. Will the PVC give enough spacing from the siding to avoid detuning the twin lead as is or will I have to move the pipe a bit off the house for additional safety?

Thanks!

KO1D
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K2CMH
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Posts: 278




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« Reply #1 on: November 15, 2011, 11:49:58 AM »

> I am not one to run a lot of power and the open wife will probably never have more than 200w on it.

I can never get more than 100w on my open 'wife'    Grin
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KO1D
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Posts: 387




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« Reply #2 on: November 15, 2011, 01:12:12 PM »

LOL yes she only runs QRP sadly!

Typos aside...should read wire (obviously)

Never drink and drive, cross red and black wires or type while still working on your morning caffeine!
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W5LZ
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Posts: 477




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« Reply #3 on: November 26, 2011, 01:57:56 AM »

Will PVC pipe keep parallel feed lines from being affected by metal nearby?  No, it won't.  About the only thing that will lessen any affect is distance, something on the order of 4 times the width of the parallel line.  Another 'trick' is to 'spiral' that parallel line.  There's still an affect, but the 'spiraling' tends to "even it out", sort of, one half of the line isn't affected more than the other.  Remember the stand-off insulators used with old TV twin-lead?  They work, not exactly the best in the world, but they still work.
 - Paul
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W8JI
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« Reply #4 on: November 26, 2011, 04:36:07 AM »

+1 on the open wire is a problem.

Doesn't mean it won't seem to be OK  and make you happy, but that open wire will be coupling to everything around it for several inches.

I'm glad I looked at my typos. That would have been offensive.

73 Tom
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