Author Topic: Slim Jim close to the PVC Mast?  (Read 5289 times)

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GreekMan

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Slim Jim close to the PVC Mast?
« on: July 06, 2016, 04:35:03 AM »
I wonder if there will be an effect on the PVC mast on the Slim-Jim antenna I will be putting there.

I mean since the SlimJimmust have something to hang from I am thinkign of making a mast for it out of sections of PVC.

ghrit

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Re: Slim Jim close to the PVC Mast?
« Reply #1 on: July 06, 2016, 06:54:07 AM »
PVC is not conductive, so there should be no problem at all.
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spacecase0

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Re: Slim Jim close to the PVC Mast?
« Reply #2 on: July 06, 2016, 11:24:02 AM »
the dielectric qualities of the PVC are not enough to mess it up
(at least not that I can measure with mine)

GreekMan

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Re: Slim Jim close to the PVC Mast?
« Reply #3 on: July 06, 2016, 01:15:47 PM »
hmmm...I am asking because i heard elsewhere that putting the antenna into the PVC changes its tuning.
Thanks!

spacecase0

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Re: Slim Jim close to the PVC Mast?
« Reply #4 on: July 06, 2016, 01:23:56 PM »
the dielectric qualities of the plastic will change the velocity factor
so theoretically it can change your tuning
but I have not seen a big enough change to mess up my home made slim jim antenna
so you are likely fine
testing will tell you for sure

GreekMan

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Re: Slim Jim close to the PVC Mast?
« Reply #5 on: July 07, 2016, 01:55:32 AM »
of course...should have thought it myself

AD

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Re: Slim Jim close to the PVC Mast?
« Reply #6 on: July 07, 2016, 07:09:59 AM »
GM

Can you provide references on the PVC tuning issue?  I would like to look at that.
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spacecase0

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Re: Slim Jim close to the PVC Mast?
« Reply #7 on: July 07, 2016, 11:08:54 AM »
I know that last question was not directed at me,

dielectric constant of PVC is about 3 ( http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm )
so with that info,
here is a good page telling how dielectric constant changes velocity factor
http://www.antennex.com/w4rnl/col0105/amod83.html
read just  the conclusion at the end if you are trying to save time

GreekMan

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Re: Slim Jim close to the PVC Mast?
« Reply #8 on: July 07, 2016, 11:44:41 AM »
Can you provide references on the PVC tuning issue?  I would like to look at that.

there was mention of it in an early guerrillaGeek/guerillacomms video when he was settign up his home antenna mast

Tempstar

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Re: Slim Jim close to the PVC Mast?
« Reply #9 on: July 12, 2016, 04:48:58 AM »
I know I have put antennas in PVC including a repeater antenna on the beachfront to keep the fiberglass from rotting from UV. Never had a problem with tuning or with even being able to tell I did it.
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RonG

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Re: Slim Jim close to the PVC Mast?
« Reply #10 on: July 27, 2016, 01:16:56 PM »
It depends on the PVC. I had a long conversation with Edison Fong Phd. who teaches high  level electronics at UCLA and he found that some PVC will drastically change the properties of the antennna.

I dont have the information at hand, but google him and the antennas he sells (excellent antennas by the way) and read the posted infora=mation. He provides produce information for home depot and lows of the type of PVC pipe that does not cause problems.

AD

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Re: Slim Jim close to the PVC Mast?
« Reply #11 on: July 27, 2016, 02:17:12 PM »
RonG

Thanks for that info and thanks for joining the site. 

Looking fwd to learning more about you and your experiences.
The only dumb question is the one that did not get asked!!