Re: [Repeater-Builder] Re: 2M Vertical Dipoles
I have used schedule 40 PVC for several antennas from HF thru 440 MHz without a problem. It does have a dielectric effect however that you must take into account. There is another plastic pipe called CPVC that does absorb RF at the higher frequencies. You don't want to use that. To make sure your plastic pipe will work ok, do the microwave test. Put a short length of the plastic pipe in a microwave along with a coffee mug filled with water. Run the microwave for a while. Then see if the plastic gets hot. If it does, you don't want to use it for RF. 73 and aloha, Eric KH6CQ --- On Wed, 8/12/09, AJ wrote: From: AJ Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles To: Repeater-Builder@yahoogroups.com Date: Wednesday, August 12, 2009, 5:05 AM Does really PVC absorb or RF or just act as a dielectric? The reason I ask is I'm looking at encasing an antenna project for the sake of weatherproofing and PVC would fit the bill rather easily. 73, AJ, K6LOR On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote: AJ, if you replace the steel mast with a fiberglass one, won't you still have the metallic feed line there? Doesn't PVC absorb RF? 73, Mike AJ wrote: On this same topic of the mast-less Antennex/Laird dipole arrays, has anyone attempted to top mount these from a fiberglass mast to minimize interaction with the normal steel pole? I have quite a few surplus fiberglass poles left that would likely work, even for side mounting on 1/2 wave spacing from the tower... On that same note, does anyone have construction plans for a dipole array (not necessarily folded dipoles)? I remember seeing a set of plans somewhere quite a while ago - we're thinking of constructing one but encasing the dipoles in fiberglass or PVC to try to protect from the weather and debris at our site (top of a large farm field)... 73, AJ, K6LOR __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
I see that YAHOO added spaces to the links in my last post. Remove the spaces to make the links work. 73 - Jim W5ZIT --- On Wed, 8/12/09, Jim Brown wrote: From: Jim Brown Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles To: Repeater-Builder@yahoogroups.com Date: Wednesday, August 12, 2009, 10:43 AM There is a definite dielectric effect for slipping an antenna inside a PVC pipe. Here are a couple of antennas that I build to insert inside PVC and both have to be final tuned while inserted inside the support pipe. http://sbarcnm. org/forum/index.php?topic=83.0 http://sbarcnm. org/forum/index.php?topic=58.0 I built one version of the first one listed to slip inside a fiberglass radome from a defunct commercial antenna using RG-213 and one half inch copper tubing for the sleeves. I had to use a shorted matching stub to get a decent SWR from this setup. 73 - Jim W5ZIT ,___
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
There is a definite dielectric effect for slipping an antenna inside a PVC pipe. Here are a couple of antennas that I build to insert inside PVC and both have to be final tuned while inserted inside the support pipe. http://sbarcnm.org/forum/index.php?topic=83.0 http://sbarcnm.org/forum/index.php?topic=58.0 I built one version of the first one listed to slip inside a fiberglass radome from a defunct commercial antenna using RG-213 and one half inch copper tubing for the sleeves. I had to use a shorted matching stub to get a decent SWR from this setup. 73 - Jim W5ZIT --- On Wed, 8/12/09, AJ wrote: From: AJ Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles To: Repeater-Builder@yahoogroups.com Date: Wednesday, August 12, 2009, 10:05 AM Does really PVC absorb or RF or just act as a dielectric? The reason I ask is I'm looking at encasing an antenna project for the sake of weatherproofing and PVC would fit the bill rather easily. 73, AJ, K6LOR On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote: AJ, if you replace the steel mast with a fiberglass one, won't you still have the metallic feed line there? Doesn't PVC absorb RF? 73, Mike AJ wrote: On this same topic of the mast-less Antennex/Laird dipole arrays, has anyone attempted to top mount these from a fiberglass mast to minimize interaction with the normal steel pole? I have quite a few surplus fiberglass poles left that would likely work, even for side mounting on 1/2 wave spacing from the tower... On that same note, does anyone have construction plans for a dipole array (not necessarily folded dipoles)? I remember seeing a set of plans somewhere quite a while ago - we're thinking of constructing one but encasing the dipoles in fiberglass or PVC to try to protect from the weather and debris at our site (top of a large farm field)... 73, AJ, K6LOR
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
I just happen to be today building a simple 12 meter 1/4 wave vertical using
this PVC I picked up at Lowes yesterday. I am using the pipe for a sleeve to
insulate the bottom 18 inches of the Aluminum tubing of the vertical from its
mounting pipe.
It says on the PVC pipe I purchased .."Rigid Nonmetallic Conduit
Aboveground and Underground Schedule 40".. made by Cantex
(http://www.cantexinc.com/
I am using a 1 inch diameter PVC with fairly thick walls. The antenna is fairly
short and lightweight, being only 112 inches long, so it should hold up well.
This is for my 12 meter beacon I will have on the air soon which will be next
to my 10 meter beacon already going on 28.2185 MHz. Both antennas are on the
top of my metal garage.
Roger W5RDW
Murphy, Texas
- Original Message -
From: AJ
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, August 12, 2009 10:13 AM
Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles
The product I'm looking at specifically is branded as "non metallic rigid PVC
conduit" sold locally at Lowes:
http://www.carlon.com/Product_CarlonPlus4080.html
On Wed, Aug 12, 2009 at 9:10 AM, Barry wrote:
some does ,test a piece in the microwave
To: Repeater-Builder@yahoogroups.com
From: aj.grant...@gmail.com
Date: Wed, 12 Aug 2009 09:05:55 -0600
Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles
Does really PVC absorb or RF or just act as a dielectric?
The reason I ask is I'm looking at encasing an antenna project for the sake
of weatherproofing and PVC would fit the bill rather easily.
73,
AJ, K6LOR
On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote:
AJ, if you replace the steel mast with a fiberglass one,
won't you still have the metallic feed line there?
Doesn't PVC absorb RF?
73,
Mike
AJ wrote:
On this same topic of the mast-less Antennex/Laird dipole arrays, has
anyone attempted to top mount these from a fiberglass mast to minimize
interaction with the normal steel pole? I have quite a few surplus fiberglass
poles left that would likely work, even for side mounting on 1/2 wave spacing
from the tower...
On that same note, does anyone have construction plans for a dipole
array (not necessarily folded dipoles)? I remember seeing a set of plans
somewhere quite a while ago - we're thinking of constructing one but encasing
the dipoles in fiberglass or PVC to try to protect from the weather and debris
at our site (top of a large farm field)...
73,
AJ, K6LOR
Click Here View photos of singles in your area
RE: [Repeater-Builder] Re: 2M Vertical Dipoles
Nuke a test piece and see if it gets hot. Chris Kb0wlf From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of AJ Sent: Wednesday, August 12, 2009 10:06 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles Does really PVC absorb or RF or just act as a dielectric? The reason I ask is I'm looking at encasing an antenna project for the sake of weatherproofing and PVC would fit the bill rather easily. 73, AJ, K6LOR On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote: AJ, if you replace the steel mast with a fiberglass one, won't you still have the metallic feed line there? Doesn't PVC absorb RF? 73, Mike AJ wrote: On this same topic of the mast-less Antennex/Laird dipole arrays, has anyone attempted to top mount these from a fiberglass mast to minimize interaction with the normal steel pole? I have quite a few surplus fiberglass poles left that would likely work, even for side mounting on 1/2 wave spacing from the tower... On that same note, does anyone have construction plans for a dipole array (not necessarily folded dipoles)? I remember seeing a set of plans somewhere quite a while ago - we're thinking of constructing one but encasing the dipoles in fiberglass or PVC to try to protect from the weather and debris at our site (top of a large farm field)... 73, AJ, K6LOR No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.392 / Virus Database: 270.13.45/2287 - Release Date: 08/12/09 06:09:00
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
The product I'm looking at specifically is branded as "non metallic rigid PVC conduit" sold locally at Lowes: http://www.carlon.com/Product_CarlonPlus4080.html On Wed, Aug 12, 2009 at 9:10 AM, Barry wrote: > > > some does ,test a piece in the microwave > > -- > To: Repeater-Builder@yahoogroups.com > From: aj.grant...@gmail.com > Date: Wed, 12 Aug 2009 09:05:55 -0600 > Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles > > > > Does really PVC absorb or RF or just act as a dielectric? > > The reason I ask is I'm looking at encasing an antenna project for the sake > of weatherproofing and PVC would fit the bill rather easily. > > 73, > AJ, K6LOR > > On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote: > > > AJ, if you replace the steel mast with a fiberglass one, > won't you still have the metallic feed line there? > > Doesn't PVC absorb RF? > > > 73, > Mike > > > > AJ wrote: > > > On this same topic of the mast-less Antennex/Laird dipole arrays, has > anyone attempted to top mount these from a fiberglass mast to minimize > interaction with the normal steel pole? I have quite a few surplus > fiberglass poles left that would likely work, even for side mounting on 1/2 > wave spacing from the tower... > On that same note, does anyone have construction plans for a dipole array > (not necessarily folded dipoles)? I remember seeing a set of plans somewhere > quite a while ago - we're thinking of constructing one but encasing the > dipoles in fiberglass or PVC to try to protect from the weather and debris > at our site (top of a large farm field)... > 73, > AJ, K6LOR > > > > > -- > Click Here View photos of singles in your > area<http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fdating%2Eninemsn%2Ecom%2Eau%2Fsearch%2Fsearch%2Easpx%3Fexec%3Dgo%26tp%3Dq%26gc%3D2%26tr%3D1%26lage%3D18%26uage%3D55%26cl%3D14%26sl%3D0%26dist%3D50%26po%3D1%26do%3D2%26trackingid%3D1046138%26r2s%3D1&_t=773166090&_r=Hotmail_Endtext&_m=EXT> > > >
RE: [Repeater-Builder] Re: 2M Vertical Dipoles
some does ,test a piece in the microwave To: Repeater-Builder@yahoogroups.com From: aj.grant...@gmail.com Date: Wed, 12 Aug 2009 09:05:55 -0600 Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles Does really PVC absorb or RF or just act as a dielectric? The reason I ask is I'm looking at encasing an antenna project for the sake of weatherproofing and PVC would fit the bill rather easily. 73, AJ, K6LOR On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote: AJ, if you replace the steel mast with a fiberglass one, won't you still have the metallic feed line there? Doesn't PVC absorb RF? 73, Mike AJ wrote: On this same topic of the mast-less Antennex/Laird dipole arrays, has anyone attempted to top mount these from a fiberglass mast to minimize interaction with the normal steel pole? I have quite a few surplus fiberglass poles left that would likely work, even for side mounting on 1/2 wave spacing from the tower... On that same note, does anyone have construction plans for a dipole array (not necessarily folded dipoles)? I remember seeing a set of plans somewhere quite a while ago - we're thinking of constructing one but encasing the dipoles in fiberglass or PVC to try to protect from the weather and debris at our site (top of a large farm field)... 73, AJ, K6LOR _ View photos of singles in your area Click Here http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fdating%2Eninemsn%2Ecom%2Eau%2Fsearch%2Fsearch%2Easpx%3Fexec%3Dgo%26tp%3Dq%26gc%3D2%26tr%3D1%26lage%3D18%26uage%3D55%26cl%3D14%26sl%3D0%26dist%3D50%26po%3D1%26do%3D2%26trackingid%3D1046138%26r2s%3D1&_t=773166090&_r=Hotmail_Endtext&_m=EXT
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
Does really PVC absorb or RF or just act as a dielectric? The reason I ask is I'm looking at encasing an antenna project for the sake of weatherproofing and PVC would fit the bill rather easily. 73, AJ, K6LOR On Mon, Aug 10, 2009 at 9:49 AM, AA8K73 GMail wrote: > > AJ, if you replace the steel mast with a fiberglass one, > won't you still have the metallic feed line there? > > Doesn't PVC absorb RF? > > > 73, > Mike > > > > AJ wrote: > >> >> On this same topic of the mast-less Antennex/Laird dipole arrays, has >> anyone attempted to top mount these from a fiberglass mast to minimize >> interaction with the normal steel pole? I have quite a few surplus >> fiberglass poles left that would likely work, even for side mounting on 1/2 >> wave spacing from the tower... >> On that same note, does anyone have construction plans for a dipole array >> (not necessarily folded dipoles)? I remember seeing a set of plans somewhere >> quite a while ago - we're thinking of constructing one but encasing the >> dipoles in fiberglass or PVC to try to protect from the weather and debris >> at our site (top of a large farm field)... >> 73, >> AJ, K6LOR >> >>
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
Hmm, that would make sense... Back to the drawing board :) On Mon, Aug 10, 2009 at 11:15 AM, Kevin Custer wrote: > > > Paul Plack wrote: > > If you mount the array on a non-conductive pole, won't you then have to > model the effects of interaction with the outside of the coax shields of the > feedline harness that would normally be insignificant when attached to the > side of a conductive pole? > > > > Be careful hereSome dipole arrays, like the cushcraft, requires a > metallic support pole to obtain/maintain the 50 ohm feedpoint impedance. > > Kevin > > >
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
Paul Plack wrote: If you mount the array on a non-conductive pole, won't you then have to model the effects of interaction with the outside of the coax shields of the feedline harness that would normally be insignificant when attached to the side of a conductive pole? Be careful hereSome dipole arrays, like the cushcraft, requires a metallic support pole to obtain/maintain the 50 ohm feedpoint impedance. Kevin
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
If you mount the array on a non-conductive pole, won't you then have to model the effects of interaction with the outside of the coax shields of the feedline harness that would normally be insignificant when attached to the side of a conductive pole? - Original Message - From: AJ To: Repeater-Builder@yahoogroups.com Sent: Monday, August 10, 2009 9:27 AM Subject: Re: [Repeater-Builder] Re: 2M Vertical Dipoles On this same topic of the mast-less Antennex/Laird dipole arrays, has anyone attempted to top mount these from a fiberglass mast to minimize interaction with the normal steel pole? I have quite a few surplus fiberglass poles left that would likely work, even for side mounting on 1/2 wave spacing from the tower...
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
On this same topic of the mast-less Antennex/Laird dipole arrays, has anyone attempted to top mount these from a fiberglass mast to minimize interaction with the normal steel pole? I have quite a few surplus fiberglass poles left that would likely work, even for side mounting on 1/2 wave spacing from the tower... On that same note, does anyone have construction plans for a dipole array (not necessarily folded dipoles)? I remember seeing a set of plans somewhere quite a while ago - we're thinking of constructing one but encasing the dipoles in fiberglass or PVC to try to protect from the weather and debris at our site (top of a large farm field)... 73, AJ, K6LOR On Mon, Aug 10, 2009 at 9:17 AM, Paul Dumdie wrote: > > > > If you want Laird / Antenex does make a 2 and 4 dipole array for the 2 > meter band the part number is YDA1362 for a 2 dipole 136-150 antenna and > YDA1364 for the 4 dipole antenna. They don't come with a mast pipe like the > cushcraft antennas from long ago. They have a YDA2004 for 200-225 MHZ > and a YDA4304 for 430-450 MHZ. They all come with the dipoles and the > harness and you supply the mast pipe or it can be ordered with the antenna. > > I am ordering one of the YDA1362 to check out how they work. > > Now that amateur line of Cushcraft has been absorbed by MFJ it will be > interesting to see what happens to the line of Cushcraft antennas. > > Paul R. Dumdie Jr. "73" > W9DWP/R IRLP-NODE-4455 > 443.025/2A 145.270/1B/1Z/NAC-293 > ARC-Radio-8 KCARES KCAPS > HERD546 EX WB9QWZ > WQGG738-462.725 AAR5CU/T > www.riflesandradios.com > www.theherd.com > >
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
Comtech I believe has the modeling for antenna side mounting from tower and it's affect on gain... On Sun, Aug 9, 2009 at 7:14 PM, wrote: > > > At 8/9/2009 16:41, you wrote: > > What was the spacing between the tower legs at the mounting location of > > the dipoles in your model? > > No tower. Only the rooftop-mounted mast & 4 dipoles, which is what I was > using at the time. > > Bob NO6B > > >
Re: [Repeater-Builder] Re: 2M Vertical Dipoles
At 8/9/2009 16:41, you wrote: > What was the spacing between the tower legs at the mounting location of > the dipoles in your model? No tower. Only the rooftop-mounted mast & 4 dipoles, which is what I was using at the time. Bob NO6B
