| Author |
Message |
    
Bulldog
| | Posted on Wednesday, August 08, 2001 - 5:55 pm: | 
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Has anybody ever tried a home made J-pole on 11 meters? I use a homebrew J-pole on 2 meters and it works great (even on ssb) But thought I would ask before buying that much copper pipe!
Bulldog |
Tech181 (Tech181)
| | Posted on Wednesday, August 08, 2001 - 11:55 pm: |
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Bulldog,
Never built one, but if you have detailed plans send them to me. I enjoy experiementing with antennas.
Steve
Tech181
Tech181@copperelectronics.com |
bruce
| | Posted on Thursday, August 09, 2001 - 9:40 am: |
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THe J pole can be found in several ARRL ant books it is a 3/4 wave ant fed with a 1/4 wave stub they are easy to build and work well |
HAM CBer
| | Posted on Thursday, August 09, 2001 - 1:22 pm: |
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The old Avanti Astro Plane Radiator was basically a J-pole with capacitive top loading. The reason for the capacitive hat instead of a vertical radiator was to get more current flowing in the vertical element going downward.
I think the Astro Plane design is still being re-made by CTE now. At least last time I looked, you can still buy one from CTE. CTE calls them the 'Top One' or something like that. I have one and It's the best antenna I have ever owned.
Performance wise.... AWESOME! Great ears and great transmit. Mostly due to the fact that the angle of radiation is lower, not because of gain in the isotropic sense. Since a J-pole is not end fed, there is less ground reflection and ground capacitance than there is with an antenna like an A99 or similar. What this means is, you waste less power warming up the ground and get more power on the horizon.
Oh, and it will handle more than 10 KW.... |
HAM CBer
| | Posted on Friday, August 10, 2001 - 2:04 am: |
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Oh, almost forgot!! Here's the website with information on the CTE version of the Astro Plane: http://www.cis.net/~kingpop/Amateur/Top-one.htm
This is the Astro Plane copy I have and its construction and materials are superior even to the original. |
HAM CBer
| | Posted on Friday, August 10, 2001 - 1:59 am: |
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I found a link to the website that sells an Astro Plane copy antenna: http://www.retrocom.com/retroantennas.htm
According to the website, they are currently out of stock, but are 'looking for more' whatever that means.
I was lucky enough to find a CTE copy locally and I am really pleased with it. |
707
| | Posted on Saturday, August 11, 2001 - 5:26 pm: |
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The Astroplane was always a good antenna for me. I put one up against a 5/8 ground plane, on separate ends of the house, and found the Astroplane to be somewhat quieter on receive, and got the same coverage on transmit. |
hoopguitar
| | Posted on Sunday, August 12, 2001 - 8:55 am: |
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HAM CBER,
Have you checked out Signal Engineering's "Golden Rod 180 S"? Let us know what you think. |
HAM CBer
| | Posted on Sunday, August 12, 2001 - 10:59 pm: |
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I have seen pictures of the Golden Rod, but I have not handled one in person.
Wanna send one over for a run on the test range??? |
707
| | Posted on Monday, August 13, 2001 - 12:58 pm: |
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sorry- should have specified I was looking at the Thunder8 |
707
| | Posted on Monday, August 13, 2001 - 12:57 pm: |
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hey hoopguitar-
looks like with a little switch rewire, some match work and a couple of extra coax leads you could make that into a 4 directional or omni beam. Maybe you guys could revive the 'ol Super Scanner concept. |
Hoopguitar
| | Posted on Monday, August 13, 2001 - 10:34 pm: |
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Hey 707,
That's allright, I've run a Super Scanner since '75. Actually I've had two--lightning got the first one. Interesting idea on the Thunder 8.
HAMCBer, wish I had a Golden Rod to send you to test "home on the range". |
Nobody077
New member
Username: Nobody077
Post Number: 5
Registered: 4-2004
| | Posted on Monday, April 26, 2004 - 1:19 am: |
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J-poles for 11m are BIG I helped a local ham build a 10m J-pole and they work good. If you build it Use 1in copper and use the thick walled type for strength, also you will need to build some support/spreaders for the matching stub, I used plexyglass for the one I built but you could also use wood. I also like to make the long element 5/8 wave instead of 3/4 wave. 5/8th wave has a slightly lower angle of radition than 3/4 does. |
Bullet
Intermediate Member
Username: Bullet
Post Number: 325
Registered: 7-2003
| | Posted on Monday, April 26, 2004 - 7:27 pm: |
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ive got 3 sets of plans for these for 11 meters.
one a regular copper j pole. another a super j pole,and a 5/4 type colinear.
the reg j pole will work fine for normal use the others require more tower and stand offs to help suport them.(big) |
Dindin
Member
Username: Dindin
Post Number: 77
Registered: 2-2004
| | Posted on Monday, April 26, 2004 - 8:57 pm: |
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077 and Bullet,I know what you mean by big!I worked up the dimensions for an 11-meter J pole about a year ago.the size and price of copper,I ended up putting that one on a back burner.In the future perhaps.Also anyone considering building one should consider using silver-solder for strengh not the 50/50 or 95/5 plumbers use these days.The silver I'm refering to is what a/c tech's use to solder refridgerant lines and fittings.After all,thats a big chunk of copper you'll be sticking up in the air. |
Allagator
Intermediate Member
Username: Allagator
Post Number: 261
Registered: 9-2002
| | Posted on Wednesday, April 28, 2004 - 4:32 pm: |
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here guys is what i used to start mine !!http://packetradio.com/jpol.htm
got it almost done now i have to get it stood up but having problems on how to get it up there with out bending to much 26 foot of 1 inch copper pipe isnt lite at all !!!!!! i mite hoist it up in a tree for now !!! |
Mikefromms
Intermediate Member
Username: Mikefromms
Post Number: 166
Registered: 6-2003
| | Posted on Tuesday, May 18, 2004 - 10:15 am: |
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Could you build one using old aluminium elements from beams or groundplanes? Wouldn't aluminum be much lighter and perform well?
mikefromms |
Dindin
Intermediate Member
Username: Dindin
Post Number: 118
Registered: 2-2004
| | Posted on Tuesday, May 18, 2004 - 8:49 pm: |
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Mikefromms,
you definetaly could use al to construct a j-pole.the advantage of copper is the ability to solder it together eliminating a joint that could oxidize and de-tune the antenna or create metal to metal static.also the availibility of copper elbows simplifies construction.you also have to consider size to strengh ratio,using larger tubing would change tuning bandwith and tuning lengh.for me copper is in better supply than al.By the time you pay shipping on al tubing,copper ends up the better deal.
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