Antenna Encased in PVC
 

I built a "J" pole out of 300 ohm inlead wire and have it trimmed where at
147.210 I have a SWR of 1.6 and on the low end at around 145.390 I have 1.2.

To protect it, I put in a 1" PVC pipe and now the SWR is way off the scale.
Is it a bad idea to encase it in PVC or can I trim it down to get a better
reading?

Thanks

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Email no good, reply to group

JE wrote:

I built a "J" pole out of 300 ohm inlead wire and have it trimmed where at
147.210 I have a SWR of 1.6 and on the low end at around 145.390 I have 1.2.

To protect it, I put in a 1" PVC pipe and now the SWR is way off the scale.
Is it a bad idea to encase it in PVC or can I trim it down to get a better
reading?

Assuming your PVC is non-conducting, it may be changing the
velocity factor. Trimming would be the way to go.
--
73, Cecil http://www.qsl.net/w5dxp


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Thanks Cecil. Any other kind of material I could use that might be better?

Thanks,
Jack


"Cecil Moore" wrote in message
...
JE wrote:

I built a "J" pole out of 300 ohm inlead wire and have it trimmed where
at 147.210 I have a SWR of 1.6 and on the low end at around 145.390 I
have 1.2.

To protect it, I put in a 1" PVC pipe and now the SWR is way off the
scale. Is it a bad idea to encase it in PVC or can I trim it down to get
a better reading?

Assuming your PVC is non-conducting, it may be changing the
velocity factor. Trimming would be the way to go.
--
73, Cecil http://www.qsl.net/w5dxp


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If you place it into a plastic pipe the resonant length will be shorter
Art
"JE" wrote in message
...
Thanks Cecil. Any other kind of material I could use that might be
better?

Thanks,
Jack


"Cecil Moore" wrote in message
...
JE wrote:

I built a "J" pole out of 300 ohm inlead wire and have it trimmed where
at 147.210 I have a SWR of 1.6 and on the low end at around 145.390 I
have 1.2.

To protect it, I put in a 1" PVC pipe and now the SWR is way off the
scale. Is it a bad idea to encase it in PVC or can I trim it down to get
a better reading?

Assuming your PVC is non-conducting, it may be changing the
velocity factor. Trimming would be the way to go.
--
73, Cecil http://www.qsl.net/w5dxp


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News==----
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Newsgroups
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JE wrote:
Thanks Cecil. Any other kind of material I could use that might be better?

I believe that many commercial antennas are enclosed in
PVC. Assuming your PVC is non-conductive, it is simply
lowering the velocity factor of your antenna (assuming
you haven't turned it into a fractal by stuffing from
one end :-). Try trimming it. If you ruin it, build
another. Or just build yourself a J-Pole from copper
tubing.
--
73, Cecil http://www.qsl.net/w5dxp


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Thanks for all the help, both of you guys!!

I trimmed little "smidges" several times and I'm back in the ballpark with
the SWR!!

Appreciate all of you help. This is my first time at tackleing something
like this.

Thanks again,
Jack


"Cecil Moore" wrote in message
...
JE wrote:
Thanks Cecil. Any other kind of material I could use that might be
better?

I believe that many commercial antennas are enclosed in
PVC. Assuming your PVC is non-conductive, it is simply
lowering the velocity factor of your antenna (assuming
you haven't turned it into a fractal by stuffing from
one end :-). Try trimming it. If you ruin it, build
another. Or just build yourself a J-Pole from copper
tubing.
--
73, Cecil http://www.qsl.net/w5dxp


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
News==----
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Newsgroups
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what sort of PVC pipe??? MUST be WHITE communications type
otherwise the carbon in it stuffs the setting
"JE" wrote in message
...
Thanks for all the help, both of you guys!!

I trimmed little "smidges" several times and I'm back in the ballpark with
the SWR!!

Appreciate all of you help. This is my first time at tackleing something
like this.

Thanks again,
Jack


"Cecil Moore" wrote in message
...
JE wrote:
Thanks Cecil. Any other kind of material I could use that might be
better?

I believe that many commercial antennas are enclosed in
PVC. Assuming your PVC is non-conductive, it is simply
lowering the velocity factor of your antenna (assuming
you haven't turned it into a fractal by stuffing from
one end :-). Try trimming it. If you ruin it, build
another. Or just build yourself a J-Pole from copper
tubing.
--
73, Cecil http://www.qsl.net/w5dxp


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
News==----
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Newsgroups
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