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Author Topic: Flagpole antenna ideas  (Read 1920 times)
WD4MKQ
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Posts: 21




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« on: August 19, 2003, 02:17:14 PM »

I live in the historic section of my town, and have some pretty heavy restrictions on what I can do antenna-wise.  I believe I can put up a flagpole without any trouble from the heritage zoning commission, but wonder about the mechanics of it.  

As I understand it, the vertical segment must be isolated from ground, so I'm guessing I'll have to mount the flagpole on a pvc pipe and then bury the pipe, rather than burying the wide end of the flagpole in concrete as recommended by the manufacturer.  I am also guessing I would load the antenna through a bolt or something to make a good electrical connection and the other side of the transmission line to the radial system.

I can see three options for loading:
 
1) RG-8 with center to the vertical and braid to the ground/tuner

2) 400 ohm ladder line/tuner

3) SGC Smarttuner at the antenna site


For use on 40/75/80, I envisioned an invisible wire from the top of the vertical to a tree or the house or something to extend the electrical length of the antenna.

WHAT A PAIN!  I can't wait until I can put up that 100 foot tower someday. :-)

any ideas would be great.

de WD4MKQ

--steve

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WB2WIK
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Posts: 20540




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« Reply #1 on: August 19, 2003, 03:16:15 PM »

A lot has been written on this subject, and before you start your project, I'd recommend you look at the flagpole vertical designs contained in the handbooks, like the ARRL STEALTH ANTENNA book -- it will answer most of your questions.

I wouldn't feed a "stealth flagpole vertical" with 450 Ohm ladder line because this would involve burying the cable, which is tricky with balanced line -- not impossible, but more effort than it's worth.

Coax is much more forgiving when it comes to burying it.  The idea of using an automatic remote tuner at the base of the antenna is great and will help provide more usable results on multiple bands with a simple antenna design.  Some of the articles published on this subject show exactly that -- an auto tuner hidden at the base of a flagpole vertical, with the tuner inside a flower box.

73 & good DXing!

WB2WIK/6
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WD4MKQ
Member

Posts: 21




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« Reply #2 on: August 19, 2003, 04:50:07 PM »

Thanks!  I wasn't aware of the Stealth Antenna Book...I'll give it a look.  I really wanted to get going with this asap but I can see that patience will pay off in the long run.

73 es tnx!


--steve
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N7NBB
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Posts: 381


WWW

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« Reply #3 on: August 20, 2003, 10:50:55 AM »

Don't know how "HISTORIC" your site is, but if it is likely to have the general public wandering around the grounds... or heck, even FAMILY or NEIGHBORS in the area, you will need to find a way to "PROTECT" the innocent from unintentionally becoming part of the antenna - and getting nasty RF burns in the process.

If indeed there is a "flag", then you will have to address the hailyard(sp)ropes / chains /pulley(s) generating metal to metal noise against the antenna.  A Cloth Flag will help reduce any static noise over that from a NYLON flag.

But I think the main issue is SAFETY !
Be sure to document (and retain on file) your RF site Evaluation for all power levels and frequencies you intend on operating on.

73 and best of luck with your - er ... ah  "FLAGPOLE"
project.

CAM - N7NBB
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KG4RUL
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Posts: 2676


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« Reply #4 on: August 21, 2003, 08:16:49 AM »

Think about making the flagpole the center of a planting area.  This will make it very difficult to actually touch it.  Also, try building a box around the base that is tall enough to hide the insulator section, coax, etc. and possibly house an antenna tuner.  This could be faced with brick, wood or other approved material.  Low profile is the watchword!

Dennis - KG4RUL
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WD4MKQ
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Posts: 21




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« Reply #5 on: August 21, 2003, 10:12:56 AM »

Sounds like a plan!  I'm concerned that the Force 12 flagpole looks just like a bunch of pipe stuck together in the photos.  Perhaps I'll simply wire a fiberglass pole for RF! :-)  If anyone has actually seen one, I'd love to hear from you.

your pal,


de WD4MKQ

steve

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WB7RBN
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Posts: 14




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« Reply #6 on: August 29, 2003, 09:43:26 AM »

Steve,

Having lived in a condo I know first hand all the problems associated with getting on the air.  I've tried wires in the attic plus one of the small loops that tune 10 through 20 meters.  Wires worked best.  If I were to move back into a condo or townhouse a flagpole would also be my choice but with a little twist. I would make the flagpole out of PVC, large enough in diameter and just long enough to house a screwdriver antenna.  That way nobody could get RF burns while I am transmitting plus the antenna is totally hidden.  The coax and control line can be buryed easily.  The more radials the better.  These can be magnet wire which is very thin.  This would give 10 through 80 meters operation on a totally invisible antenna.

Just some food for thought.

Jim  
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WD4MKQ
Member

Posts: 21




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« Reply #7 on: August 29, 2003, 09:57:18 AM »

Great minds think alike!  I had considered running a wire inside a fiberglass or pvc flagpole!  My only question to your post is, what is a "screwdriver" antenna?  This must be something that came out since I went QRT a few years ago. :-)


steve
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K1HW
Member

Posts: 42




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« Reply #8 on: October 27, 2003, 11:53:32 AM »

I have a Force 12 flagpole antenna.  It works fine
and looks like all the other flagpoles in my
neighborhood.  I added two more sections to it to get
better SWR on the lower bands so it is about 26 or
28 feet high now, but still not the highest one in our subdivision.  My home is at the entrance to the subdivision and, with the flag flying, the flagpole looks like the official flag for the subdivision.
If you buy the Force 12 with the installation kit it runs about $150 and you have everything you need except for a bag of quick drying cement.  You can have it up and installed within 3 or 4 hours.  The more time comsuming job was getting the coax around the side of the house under the eaves to the antenna.

Jack
K1HW
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KG4HNS
Member

Posts: 1




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« Reply #9 on: January 10, 2004, 03:36:36 PM »

Thanks for your idea. I've had a temporarily mounted screwdriver antenna sitting outside for several months while wondering how to make up a stealth antenna for 40 and 80 meters.  What a great idea - why didn't I think of that!
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K4CAV
Member

Posts: 152




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« Reply #10 on: February 09, 2009, 08:31:56 PM »

Here are a couple of ideas:

http://www.force12inc.com/

http://www.sgcworld.com/20ftflagpoleinstall.html

If attempting the store bought flagpole remember to remove the anodized coating at the sleeves and coax connections.

http://www.zerofive-antennas.com/

http://www.dxengineering.com/pdf/flagpole_antenna.pdf

The last link is you're BTV

I have a Force 12 Flagpole as I am in a restricted area.
It is the 20' version with 16 radials at 25' each. Have made contacts all over Europe and as far west as Hawaii.

I tend to agree with you on the loading issue. You may have to add guys to it. Unfortunately that will take away from the flagpole appearance and might become a tripping hazard.

K4CAV

 
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KQ4Y
Member

Posts: 6




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« Reply #11 on: March 23, 2009, 10:20:10 AM »

I just ordered the Force 12 antenna with an extra section to bring it to the maximum allowed here in Florida.  I've read of folks adding some wire to the top to increase the length and wonder how effective that is.  Also, does the extra amount have to be at the top?  I was thinking of adding it at the 16' level so that the flag won't hit it as it might if the extra wire were attached to the top?
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NG0K
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Posts: 335




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« Reply #12 on: March 25, 2009, 11:02:24 AM »

This is a post from 2003.  I doubt it matters now :-)
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73, Doug - NG0K
KI4VEO
Member

Posts: 166




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« Reply #13 on: March 25, 2009, 05:56:03 PM »

why wait...put up a 100 foot flagpole
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KG7MCH
Member

Posts: 6




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« Reply #14 on: April 02, 2009, 09:31:32 PM »

I am building a flagpole antenna using a hustler vertical with a 2 and a half inch PVC pipe on the outside.  Should have it up in a few weeks.
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