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Tech237
Moderator
Username: Tech237
Post Number: 1909
Registered: 4-2004
| | Posted on Thursday, January 25, 2018 - 9:10 am: | 
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OK, not allowed any antennas attached to the building or trees on the apartment complex, BUT they are letting me place pvc pipe frame on the patio with a mesh on it to stop the dogs toys from going off the patio.
This frame is going to be 2 C shaped sections 6ft on the legs and 7ft 6inches across the back with a vertical spacing of 3ft.
The challenge, should you accept it, is to help me come up with a decent multiband HF antenna that can be hidden in that frame.
Right now, I am looking at possibly making a multi-turn loop that runs from one ground level end to the opposite ground level end, then up the 3ft pipe and back around. One run gets me about 45ft or wire. If I use a piece of 8 conductor ribbon that would be a total of 360 in 8 turns.
now over to your fertile minds to come up with other options
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Tech237
Moderator
Username: Tech237
Post Number: 1911
Registered: 4-2004
| | Posted on Monday, March 19, 2018 - 10:15 am: |
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A little disappointed that no-one has come up with any suggestions for my antenna. Hey 833 what can you think up for this scenario?
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Dale
Senior Member
Username: Dale
Post Number: 2331
Registered: 12-2002
| | Posted on Tuesday, March 20, 2018 - 8:11 pm: |
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hmmm... well i never homebrewed anything but how about a full size 1 wavelenth loop antenna hidden inside the pcv.of corse you,d have to shapethe frame like a quad beam or square. might work??
dale/a.k.a.hotrod
cef426
cvc#64
454 [dx numbers]
38lsb
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Tech833
Moderator
Username: Tech833
Post Number: 2401
Registered: 8-2002
| | Posted on Sunday, March 25, 2018 - 12:58 pm: |
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You are asking to break the law of physics. A small loop will not work well on HF. I'm not saying it will not work at all, just saying that compared to a beam or a full size dipole, a loop is very disappointing.
I just recently installed a very good performing HF antenna for a friend who lives in an apartment. We went with downrigger wire that is so small, it is practically invisible. He is on the 2nd floor and I used his welded steel balcony railing as the counterpoise to feed a random wire through a 9:1 balun. On side of the balun goes to the railing, the other side goes to the wire.
The wire is in inverted L configuration with the feed at the railing level. The wire goes up to an insulator attached to a pole that is bolted to the railing and extends up about 10 feet. Then, the wire goes horizontal to an oak tree about 50 feet away. It works well on 80-10m.
As with almost any random wire antenna, a tuner is needed. His Yaesu radio has a built-in tuner and easily handles the load on any band because the 9:1 balun gets the impedance down to the tuner's range.
Your radio 'Mythbuster' since 1998
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Tech237
Moderator
Username: Tech237
Post Number: 1913
Registered: 4-2004
| | Posted on Monday, March 26, 2018 - 8:50 am: |
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I had a Slinky dipole up but they complained about that when it was spotted while they were cleaning the roof. So yes, I know about not working well.
I was hoping against hope that maybe we could find that would fit inside the pvc frame. Maybe run 22ft of wire for the antenna and 19ft for the ground inside the frame. Unfortunately wooden patio railing.
Guess it comes down to even a poor antenna is better than no antenna.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Dale
Senior Member
Username: Dale
Post Number: 2334
Registered: 12-2002
| | Posted on Monday, March 26, 2018 - 10:01 pm: |
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tech 833 i know a regular beam will be better than a loop . however his post says not allowed a antenna.
dale/a.k.a.hotrod
cef426
cvc#64
454 [dx numbers]
38lsb
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Tech833
Moderator
Username: Tech833
Post Number: 2402
Registered: 8-2002
| | Posted on Sunday, April 01, 2018 - 2:19 pm: |
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Thank you Dale. Yes, I know what his post said. The first line of my reply says, "You are asking to break the law of physics. A small loop will not work well on HF. I'm not saying it will not work at all, just saying that compared to a beam or a full size dipole, a loop is very disappointing. "
So, to expand upon and simplify my answer... What Simon proposed will work, but just barely. It is my opinion that he would be better off with an antenna hidden in plain sight over one he attempts to make very small and hidden from view.
Your radio 'Mythbuster' since 1998
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Tech237
Moderator
Username: Tech237
Post Number: 1914
Registered: 4-2004
| | Posted on Monday, April 02, 2018 - 1:23 pm: |
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833 - basically the size I quoted is all the area I have to work with. If I can get it to work on 10 and 6, I'd be happy. Anything else would be a bonus.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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