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Author Topic: Wire antenna question...  (Read 1559 times)
W4MBT
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Posts: 3




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« on: November 04, 2012, 12:19:05 PM »

Hello all,

I currently have a G5RV hanging from a tree in an inverted V configuration, with the center about 37-42 feet above ground.  The ends, however, are very near the ground and I'm hoping to better understand wire antennas in general, what would be optimal, or if this even matters much.

Will I see improvements if I raise the ends to at least 6-10 feet off the ground?  I may be able to raise the center by another 5-7 feet but I'm not sure how close I can keep the overall angle of the "V" near 90 degrees if I raise the ends by more than a few feet each.  Am I over thinking this?  I really just want to be sure I'm maximizing my TX power and not losing as much into the ground.

Thanks in advance for your replies,
73,
Matt - W4MBT
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K3VAT
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Posts: 756




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« Reply #1 on: November 04, 2012, 01:02:02 PM »

Hello all,

I currently have a G5RV hanging from a tree in an inverted V configuration, with the center about 37-42 feet above ground.  The ends, however, are very near the ground and I'm hoping to better understand wire antennas in general, what would be optimal, or if this even matters much.

Will I see improvements if I raise the ends to at least 6-10 feet off the ground?  I may be able to raise the center by another 5-7 feet but I'm not sure how close I can keep the overall angle of the "V" near 90 degrees if I raise the ends by more than a few feet each.  Am I over thinking this?  I really just want to be sure I'm maximizing my TX power and not losing as much into the ground.

Thanks in advance for your replies,
73,
Matt - W4MBT

Yes, you will see improvement by raising the ends of your inverted vee from near ground level to 10 feet (or greater).  Your current configuration with the ends very close to the ground is contributing to a large loss in antenna performance.  Plus they're a safety hazard 1) due to high voltage to humans and animals, and 2) a trip hazard.  So raising the ends and if you ALSO raise the center portion by 5-7 feet will markedly improve your system.  You really don't need to keep the angle of the vee at 90 degs; in fact, the more the vee approaches a horizontal dipole, the better!
Let us know your findings.  GL, 73, Rich, K3VAT
« Last Edit: November 04, 2012, 01:05:23 PM by K3VAT » Logged
KO7I
Member

Posts: 106




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« Reply #2 on: November 04, 2012, 01:30:31 PM »

In my humble opinion you will receive a noticable improvement in performance. For reasons of safety you should raise the ends of the antenna. All doublet style antennas will perform better when installed as flat top. Try for 33 ft for center and ends if possible. You see improved performance on 20M and up. Good luck es 73. Don KO7I.
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W4MBT
Member

Posts: 3




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« Reply #3 on: November 04, 2012, 01:37:10 PM »

Thank you both for your responses, I'll raise the ends as close to 10 feet as I can get and will see how the performance improves.

I will mention too, despite it sounding like a safety hazard I have the wire positioned in such a way that it's completely protected from anyone/anything walking past.  Smiley

Thanks again for the help!
73,
Matt
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WB6BYU
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Posts: 13477




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« Reply #4 on: November 04, 2012, 03:30:36 PM »

Having the ends near the ground reduces the efficiency.

Bending the antenna into an inverted vee reduces the efficiency slightly, but
increasing so as the angle between the legs decreases below 120 degrees
or so.

Raising the ends will make more difference than raising the center because it
improves both factors.  With enough rope on the ends of the wire (and space
to run it) you can keep the ends up at a reasonable height even if you have
to tie the ropes at ground level.

It will work best when you can get it as flat and as high as possible.
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K0ZN
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Posts: 1560




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« Reply #5 on: November 04, 2012, 07:04:59 PM »


Count me in with the "higher and closer to flat/horizontal" for best results...... especially on the higher bands.  Often, the radiation angle/plot
of the inverted V configuration is less desirable/effective on higher bands than the conventional horizontal antenna.

73,  K0ZN
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N6AJR
Member

Posts: 9921




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« Reply #6 on: November 05, 2012, 01:21:47 PM »

Take  3 pieces if 1X4 or 2X4 wood, and make a  2 legged  mount with the 3rd piece sticking up. this gives you 16 feet + or _ at the tip.  a couple or 3 light rope guys will hold them up. this will be better.  a G5RV is actually a pretty good 20 m antenna, and will work on other bands with a tuner.  you might also try a fan dipole and see what happens.  look up homebrew antennas, stealth antennas and such to get some ideas.
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W4MBT
Member

Posts: 3




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« Reply #7 on: November 06, 2012, 07:37:36 PM »

Thanks again for all of the advice.

I've figured out a way to easily get the ends of my G5RV off the ground by at least 15 feet, and I'm going to hang up an Alpha Delta wire antenna as well to see how the two compare.

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