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Non Metallic Antenna Mounting Pipes

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CK-722
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Non Metallic Antenna Mounting Pipes

Post by CK-722 » Mon Jul 27, 2020 11:40 am

I'm thinking of mounting a short light vertically polarized antenna on a PVC mast on a PVC vent pipe, to avoid reflections affecting the pattern and/or null depth.

PVC is a little flimsy if you get past a few feet. Anybody ever try reinforcing PVC pipe with a wood dowel?


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audiophile
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Re: Non Metallic Antenna Mounting Pipes

Post by audiophile » Tue Jul 28, 2020 6:54 pm

I used 2" PVC electrical conduit to support a FM yagi at 20' bracketed at 8'. Worked good.


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Mike Oxlong
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Re: Non Metallic Antenna Mounting Pipes

Post by Mike Oxlong » Wed Jul 29, 2020 10:52 pm

CK-722 wrote:
Mon Jul 27, 2020 11:40 am
I'm thinking of mounting a short light vertically polarized antenna on a PVC mast on a PVC vent pipe, to avoid reflections affecting the pattern and/or null depth.

PVC is a little flimsy if you get past a few feet. Anybody ever try reinforcing PVC pipe with a wood dowel?
Without knowing specifics, if you're mounting the antenna at the top of the mast, you're not going to get any pattern distortion, absorption or refraction from the metal mast directly under the vertical antenna.

If you got your heart set on PVC, take a look at Schedule 80 PVC. It's PVC with thick walls. A 10' piece of 2" Schedule 80 isn't going to bend on you.



k8jd
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Re: Non Metallic Antenna Mounting Pipes

Post by k8jd » Sat Aug 01, 2020 4:43 pm

Metal masts are easy to ground for lightning protection. that is a consideration if your area has a lot of thunderstorms and the mast is higher than the house roof. Metal masts with a vertical ant on top will not interfere with the directional pattern at all, since they are non directional to start.



k8jd
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Re: Non Metallic Antenna Mounting Pipes

Post by k8jd » Sat Aug 01, 2020 4:46 pm

Since the demise of on-air TV, it's getting harder to find the items we used to mount outside TV antennas, roof trippods and ,light mast sections are getting hard to find and very expensive. Gettng a VHF or UHF amateur radio antenna up is getting more expensive too !



CK-722
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Re: Non Metallic Antenna Mounting Pipes

Post by CK-722 » Sat Aug 01, 2020 9:37 pm

I was thinking of mounting a 5 element custom made directional antenna for 136-174 MHz, a homemade Yagi with modified dimensions from a homemade 174-216 MHz plan, and mounted vertically (vertical polarization). I would think that a vertical metallic pole might affect the pattern and null depth. It could be used to monitor public service that remains, weather band DX, marine band DX, etc. I am currently at a location where I have been able to hear four WB signals just by using the provided vertical whip, by moving the scanner around to different directions. I have a better telescoping antenna on order which can be changed without moving the scanner much to adjust the polarization, which varies beyond the horizon and different propagation conditions to a different polarization. I have already heard 4 WB frequencies this way.

It would also be neat to monitor and DX any Marti radio station remotes that still exist. I used to hear the WKMF remote at the South Flint Plaza on a Marti frequency near the Weather Band, and met Mike Thorp there. WTRX used to do live broadcast remotes on 170.15 MHz, including The Buick Open at Warwick Hills years ago. That one came in a good 8 miles away on a small Radio Shack analog tuned 30-50 and 108-174 VHF AM FM portable with a telescoping whip.


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Mike Oxlong
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Re: Non Metallic Antenna Mounting Pipes

Post by Mike Oxlong » Sun Aug 02, 2020 9:21 am

CK-722 wrote:
Sat Aug 01, 2020 9:37 pm
I was thinking of mounting a 5 element custom made directional antenna for 136-174 MHz, a homemade Yagi with modified dimensions from a homemade 174-216 MHz plan, and mounted vertically (vertical polarization). I would think that a vertical metallic pole might affect the pattern and null depth. It could be used to monitor public service that remains, weather band DX, marine band DX, etc. I am currently at a location where I have been able to hear four WB signals just by using the provided vertical whip, by moving the scanner around to different directions. I have a better telescoping antenna on order which can be changed without moving the scanner much to adjust the polarization, which varies beyond the horizon and different propagation conditions to a different polarization. I have already heard 4 WB frequencies this way.

It would also be neat to monitor and DX any Marti radio station remotes that still exist. I used to hear the WKMF remote at the South Flint Plaza on a Marti frequency near the Weather Band, and met Mike Thorp there. WTRX used to do live broadcast remotes on 170.15 MHz, including The Buick Open at Warwick Hills years ago. That one came in a good 8 miles away on a small Radio Shack analog tuned 30-50 and 108-174 VHF AM FM portable with a telescoping whip.
Thanks for being more specific. If the beam is going to be vertical, now you have an issue.
From the way I picture what you are saying, the mast will be in the same plane as the beam, so the mast will be a sixth out-of-resonance element.

People do run a vertical beam with the metal mast up the middle. And you can get a 1:1 match.
But it WILL cut your gain in half. Don't let no one tell 'ya different.



CK-722
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Re: Non Metallic Antenna Mounting Pipes

Post by CK-722 » Sun Aug 02, 2020 10:01 am

I talked to "Rudy", an engineer at Jampro as I recall, may be retired now, about a vertically polarized FM BC transmitting antenna we were considering, an he said that with a reflector for a DA, that the vertical tower pipes caused negligible pattern modification, from the generally three vertical pipes. That must be the out of resonance contributions. But "negligible" is not zero. I guess negligible means that they reflect like "spherical conducting chickens" in a Physics joke.


Is THAT where they got the idea for the 486-SX?

Same (x, y, z), different (t)

Your bullet missed my trial balloon.

RTN Price. Not guaranteed. As of 12:30, 157.71 Down 0.22.

Artificial Intelligence is a Child that needs a Parent to guide it through.

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