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DX-CC dipole - bending

Dec 26th 2012, 19:36

parity

Joined: Jun 2nd 2012, 17:08
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According to the AARL Antenna Book, it seems reasonable to have some dipoles bent and folded to a certain extent (chapter on indoor antennas). For use as an indoor antenna, I could bent the line in each leg of the DX-CC at 20ft (so essentially a U, where each segment of the wire would be 20ft, for a total of ~80ft). That should fit the indoor space I have in mind.

The other indoor option, which seems to work for people, would be to get the DX-EE and set it up as an inverted V. This antenna does not handle the 80m band.

The question is, would setting up the DX-CC be at all worth the trouble, or will the results in the 40-10m be much better and outweigh the additional 80m capability?
Dec 27th 2012, 16:13

W1VT

Joined: Apr 4th 1998, 00:00
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You will need to work very hard to get an antenna like the DX-EE resonating as it should after bending it like that.

But, before even considering an inside antenna, one should make sure that it has remote chance of working. If you are living in a concrete and steel structure--don't bother. You might investigate the possibility of an external flag pole antenna--taking advantage of the Freedom to Display the American Flag act of 2006.

Indoor antennas can work well if mounted in a wood frame building with good height.

Zack Lau W1VT
ARRL Senior Lab Engineer
Dec 27th 2012, 21:59

parity

Joined: Jun 2nd 2012, 17:08
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It's all wood and shingles, and the attic is on the third floor. I think I can get at least 24 ft. of elevation. A DX-EE will fit without bending... it's if I opt for the DX-CC when I need to bend the ends.
Dec 28th 2012, 03:23

W1VT

Joined: Apr 4th 1998, 00:00
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24 feet isn't very high for 80 meters--the smaller antenna makes more sense for most hams.

Zack Lau W1VT
ARRL Senior Lab Engineer
Jan 4th 2013, 00:26

KD2OY

Joined: Apr 4th 1998, 00:00
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What effect would it have to run an OCF dipole through tree
branches

KD2OY

Jan 4th 2013, 17:55

W1VT

Joined: Apr 4th 1998, 00:00
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The tree has the most effect when close to the ends of the dipole--the least near the center, where the antenna impedance is lowest. The latter allows something known as "plumber's delight" construction, where antenna elements are bolted to a boom at their centers without the use of insulators.

It is possible to start ignite objects close to the ends of antennas when operating high power, though I don't recall any cases where this occurred at the 100 watt level.

Typically, it is much better to have a big wire antenna in a tree than anything indoors.

Zack Lau W1VT
ARRL Senior Lab Engineer

Jan 5th 2013, 23:45

parity

Joined: Jun 2nd 2012, 17:08
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I bought the smaller DX-EE antenna and installed it. It hangs nicely in the attic away from metal and power lines. I bought a Yaesu 897 and an LG-AT-897plus tuner with it as well. The antenna seems to receive fairly well... for being in an attic.

I also got an SWR meter... evidently the SWR on the 40M band is way too high to even tune. On the 20M band I can only get it to transmit on AM with an SWR of 3:1 and the 10 meter band is similar. Not much luck installing this in the attic I suppose. I'll try to find a way to try it out outside.

Jan 15th 2013, 01:47

parity

Joined: Jun 2nd 2012, 17:08
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I repositioned the Antenna once more in the attic and it finally tunes much better now.
Jan 15th 2013, 13:47

W1VT

Joined: Apr 4th 1998, 00:00
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Yes, you may need to experiment with attic antennas. It typically helps to run antenna wires at right angles to electrical wiring to minimize coupling between the two systems.

Zack Lau W1VT
ARRL Senior Lab Engineer

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