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Author Topic: Antenna Opinionsw  (Read 760 times)
KB3KCJ
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Posts: 125




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« on: March 15, 2013, 07:48:56 AM »

I currently use an end-fed random wire antenna about 350 feet long.  It does perform quite well and a friend of mine has a closed loop antenna.  Anybody have any opinions about which is better?  Of course the old idiom, "Whatever works for you" may apply.  I can safely say that my antenna has never, never been blown down by high wind.
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KD0NFY
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Posts: 75




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« Reply #1 on: March 15, 2013, 09:32:04 AM »

Either one done right is a good antenna.  I think it's easier to do a loop right.  Cut it for a full wavelength on the lowest frequency band you want, and feed it with balanced line to a tuner in the shack and work all bands higher in frequency. 

My 80 meter loop is definitely nothing special on 10 meters though, but you'll have that same problem with a too-long "random" wire anyway. 

The horizontal loop is known for being quiet on receive, in my experience it's true. 
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K0CWO
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Posts: 416




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« Reply #2 on: March 15, 2013, 11:48:53 AM »

I guess it depends on what band(s) you primarily use and where you want your signal to go.  It also depends on antenna elevation and orientation.  Loops are great antennas and when fed with balanced line they couple easily to a transceiver on multiple bands using an antenna tuner.  Personally I would prefer a loop over an end fed wire any day but a loop would be diffcult for me to erect.

I have used a 165 foot end fed wire fed against a modest radial field 160-10 for years. It has survived some wicked storms were indeed I wonder if a loop would have survived.  It is finicky to match on some bands and exhibits RF issues on some bands when using QRO.  I have been able to tame the worst RF issues but I occasionally set off a carbon monoxide detector in the house.

I have always wanted to erect a  (1005:1.Cool 558 foot loop and feed it with balanced line to use on 160-10.  I know folks that use an antenna like that, I've heard them on the air, and they work great even if they aren't that high off the ground.

If you are like me and you don't care too much where your signal goes, I would certainly give a loop a try and keep your end fed wire up at the same time so you can compare them.

73, BJ
k0cwo
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OLDGEEZER
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Posts: 48




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« Reply #3 on: March 15, 2013, 12:06:12 PM »

Just a suggestion, if you have 350 ft to play with you may want to try a double extended Zeppelin, lots of info on the web.

I have one roughly cut for 3.800 on the 80 meter band, it is fed with appx. 150 feet of 450 ohm ladder line to an MFJ 919 current balun and then a short piece of RG8 thru the wall to a MFJ934 tuner in the shack.

I have not exceeded 100 watts (yet) but it tunes well on 80,40, and 20 meters, the claims are that it is a 3db gain antenna....It is much quieter on receive than my Buckmaster 7 band inverted "V"

73 Dave VE9YA
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WB6BYU
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Posts: 13007




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« Reply #4 on: March 15, 2013, 06:45:43 PM »

Quote from: KB3KCJ

...Anybody have any opinions about which is better?...



Depends what you are trying to use it for, how high it is, etc.

I've used long wires up to 600' or so, and a number of different
loops.  When properly fed any of them can work reasonably well;
the main consideration is the radiation pattern.

As a wire antenna gets longer (beyond about 5/8 wavelength), the
pattern breaks up into multiple lobes and nulls, especially on the
higher bands.  If you are happy to work in the available directions
and ignore those where you have deep nulls, they can be satisfactory.
Same with a horizontal loop:  when the perimeter is 2 wavelengths or
more the pattern is a series of lobes and nulls in various directions:
I like to use an 80m loop for Field Day, but on 15m and 10m the lobes
are so sharp that a significant number of stations fall in the nulls
(even though the ones that are in the lobes are strong.)  In this
case I have a strong signal to some stations, but not to others.  If
I'm just looking for a few good contacts it works fine:  if I'm trying
to work as many stations as possible, there are some in the nulls
that I can't reach.

Personally I've had best results with long wires that are less than
about 130' (though a 270' one got excellent reports from the
other side of the state on 75m due to the lobe placement.)  Beyond
that the lobes tend to be too narrow to be generally useful on
20m and higher bands.  The 600' long wire was a particular
disappointment on Field Day, possibly due to its orientation or height
above ground.  Similarly with horizontal loops, a full wave on 80m
is pretty good on 20m and usable on 15m if I can align the lobes
in optimum directions.  (Last year for Field Day I put up a 40m
doublet instead and worked more stations than I had on the big
loop.)

So both loops and end-fed wires can be useful in some situations, but
the patterns may not be favorable on the higher bands, depending
on your operating preferences.
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