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Author Topic: Best 2 meter vertical base antenna?  (Read 27560 times)
W4JST
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« on: May 20, 2012, 02:43:20 PM »

What's the best vertical antenna for 2 meters?

I am probably looking to make my own and use something I can pull up into the tree and not a yagi.

Are J pole's, 5/8, isopoles, or anything else better than making a vertical dipole? Please share. If there's a site online that discusses the construction of what you're talking about, please share it as well.

On a separate note:
I am also in the process of testing a 5/8 wave versus a 1/4 wave antenna on the mobile and am not finding much difference most of the time. Sometimes I am even finding the 1/4 wave outperforms the 5/8 wave.
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K1CJS
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« Reply #1 on: May 20, 2012, 04:16:10 PM »

I'll go a bit off the request here and say the a Hustler G7-144 beats just about anything around for being the best 2 meter antenna--for the money.  It will outperform homemade j-poles and 1/4 wave ground planes by quite a bit.  For a homebrew antenna, a j-pole seems to be a bit better than a 1/4 wave ground plane, but not by much.

On your mobile, the 1/4 wave and the 5/8 wave will perform about the same, with the 5/8 wave tending to keep the angle of radiation lower than the 1/4 wave.  If you're looking for good all-around useage, however, a simple 1/4 wave ground plane with an NMO mount that is hard mounted to the vehicle roof is hard to beat.  Drill the hole--you'll be glad you did.
« Last Edit: May 20, 2012, 04:19:19 PM by K1CJS » Logged
K2OWK
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« Reply #2 on: May 20, 2012, 04:37:50 PM »

Go to the website http://www.alpharubicon.com/elect/jpolejaden.htm This is a super cheep do it yourself "J Pole". This one is made from copper. I am going to try to make one out of conduet and see how it works.

73s

K2OWK
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WB6BYU
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Posts: 13239




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« Reply #3 on: May 20, 2012, 04:43:19 PM »

Quote from: W4JST

What's the best vertical antenna for 2 meters?



There isn't any such thing as the "best" antenna.  Or radio, microphone, band, or anything
else.  There may be some that fit your needs and operating preferences better than some
others do.


Quote

I am probably looking to make my own and use something I can pull up into the tree and not a yagi.

Are J pole's, 5/8, isopoles, or anything else better than making a vertical dipole? Please share. If there's a site online that discusses the construction of what you're talking about, please share it as well.



Height makes far more difference than gain.  The antenna you can get up highest is
probably going to work better than one you can't mount as high because it is heavier,
more awkward, etc.


For an omnidirectional antenna, gain is a function of overall radiator length (assuming the
antenna is properly designed.  You can make it worse than that, but not better.)  So any
antennas of about the same radiator length will have about the same gain.  This means
there is little difference in practice between a ground plane, vertical dipole, or a J-pole,
as they are all basically half wave radiators.  The ground plane on a coax connector
is simple to build, cheap, and works well.  The biggest difference you will find among
these antennas is how well they decouple the feedline from the antenna:  this is a
particular problem with a vertical dipole when the coax runs down along the lower
element (which is why a ground plane is preferred) but the J-pole is also prone to
this.  The current flowing on the coax can partially cancel the radiation from the
antenna at the horizon and raise the angle of maximum radiation.

The IsoPole is a 2 x 5/8 wave design that will have about 3dB gain over a dipole.  This
is similar to some of the "extended" J-poles, etc. that have about an 8' radiator.  There
are several construction methods.  Note that you can't use just a straight wire for the
radiator to get it to work at this length - you need some sort of phasing stub in the
middle.

I don't recommend going to any longer of a radiator, however, unless you can get it
very high in the air and ensure it is plumb, as it doesn't take much tilt to a 6dB omni to
where it is no better than a dipole in some directions.



Quote

On a separate note:
I am also in the process of testing a 5/8 wave versus a 1/4 wave antenna on the mobile and am not finding much difference most of the time. Sometimes I am even finding the 1/4 wave outperforms the 5/8 wave.


That's what most people find who compare them in practice.  The top of the typical
vehicle (even a van) is nowhere near large enough for the 5/8 wave to achieve it's
advertised gain, an the longer whip is more prone to bending over at speed and
cross-polarizing the signals.  By switching back and forth between two antennas
while driving through marginal coverage areas, I find that the 5/8 wave tends to
show a little gain over the 1/4 wave whip - perhaps the difference between 40%
copy and 60% copy.  Most of that gain is due to the fact that the active radiator
is higher in the air.
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W4JST
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« Reply #4 on: May 20, 2012, 07:26:34 PM »

WB6BYU,

Regarding the end of your post:

The 1/4 vs. 5/8 is on a Sprinter van roof. LOTS of metal. I have switched back and forth sitting still and have not yet finished testing to find out which antenna I will keep.


I understand height is a major factor at this frequency. I am looking for something I can put in a tree. The height will be the same with any antenna I can do this with, I am going to put it as high as I can in a tree.

Which design should I go with?

Thanks everyone.
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K1CJS
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« Reply #5 on: May 22, 2012, 06:16:00 AM »

...For a homebrew antenna, a j-pole seems to be a bit better than a 1/4 wave ground plane, but not by much.

In my reading the other answers, I found that I didn't include a few important words--for the purposes you want.

While it is fairly easy to raise either a j-pole or a 1/4 wave ground plane into a tree by rope, the j-pole will be better in that it will be easier to do with no radials to get in the way, and it may be better in staying strighter in that any wind blown tree limbs coming against it won't bother it in the way they may bother--and break--a ground plane antenna.  For your stated way of raising the antenna, a j-pole is best.

Added--  BTW, for mounting on a van roof, I would go with the 1/4 wave whip--for only one reason.  Height.  If you did decide on the 5/8 wave, the extra height may see you hitting things--and possibly breaking the antenna--that you wouldn't hit with a 1/4 wave whip.  The 1/4 whip is also more flexible, and if it did hit anything, the whip would give--rather than possibly the van roof.
« Last Edit: May 22, 2012, 06:20:28 AM by K1CJS » Logged
W8JX
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Posts: 5755




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« Reply #6 on: May 23, 2012, 05:40:27 PM »


I don't recommend going to any longer of a radiator, however, unless you can get it
very high in the air and ensure it is plumb, as it doesn't take much tilt to a 6dB omni to
where it is no better than a dipole in some directions.


Simply not true.  I have G7 that has been up about 16 years now and it is very windy here at times and I have never seen it "flutter" on a weak signal in fringes in gusty winds. It is up about 40ft at base. Very solid antenna in performance and ruggedness. Only flutter I have ever seen from a vertical in the wind was a 20 ft 440 station master on repeater that had multiple phased elements in stack for high gain very low radiation angle and unlike G7 it also flexed a lot in wind too. 
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W4JST
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« Reply #7 on: May 23, 2012, 06:51:50 PM »

I think a lot of people have said good things about the Hustler G7. Is it just two stacked 5/8 wave antennas?

I see a design online for a stacked 5/8 wave J pole at http://home.comcast.net/~buck0/5-8thx2j.htm

I've also heard of an isopole which I guess is about the same thing as both of the above, just stacked 5/8 wave?

Is a regular J pole any better than a vertical dipole?

It wouldn't hurt to have something usable on 446 MHz but I don't have to, I primarily want the best thing for 2 meter simplex that I can make and pull into a tree.
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W8JX
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« Reply #8 on: May 23, 2012, 07:56:16 PM »

I think a lot of people have said good things about the Hustler G7. Is it just two stacked 5/8 wave antennas?

3 stacked 5/8 wave elements
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K1CJS
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« Reply #9 on: May 24, 2012, 05:18:35 AM »

Fromn the paperwork concerning the assembly and tuning of the G7--

Quote
The G7-144 utilizes a 5/8 wave lower, 5/8 middle, 5/8 upper collinear radiator which has been spaced for optimum low angle radiation....
The total useable bandwidth is more than 2 MHz under 1.5:1 without degradation of gain which makes the antenna ideal for duplex operation.  

The adjustability of the three different sections makes this antenna a favorite for repeater owners in that it can be adjusted (with the use of the supplied chart and a good wattmeter) for minimum SWR yet is still sturdy enough to stand up to weather extremes that would play havoc with other non-commercial grade antennas.

The one I have I bought used over a decade ago.  It didn't have any of the radials with it and it was corroded to the point that multiple applications of penetrating oil had to be used to separate the different sections and the radial mounting baseplate.  After being cleaned up, reassembled, and having newly cut radials attached, the antenna behaved as if it were new.  The only thing that could be mentioned as not being the greatest would be the machining of the ends where the 5/8-24 studs screw in to attach the different sections together.

The instructions also state that a coating of a good grade acrylic lacquer can be used on the antenna after final adjustments are made.  I used Krylon spray to do that, and that rebuilt antenna has stood up well to weather here in southern New England--at two different shack sites--since I got it.  I took it down last spring to clean and recoat it, and the many different parts came apart with no problems whatsoever--they were tarnished a bit, but were just about as clean as the day I first put the antenna up years ago.

I believe that the G7 (or its newer model) lists for around two hundred dollars today, but if you're looking for a good omnidirectional 2 meter vertical antenna, the G7 would probably be your best choice.

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K1CJS
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« Reply #10 on: May 24, 2012, 05:25:04 AM »

BTW, the instructions and other paperwork on the G7 is available on the DX Engineering website.  The antenna is supplied with an N connector, and the paperwork specifically tells you not to seal the connector area because that will cause the antenna to retain water, possibly causing corrosion over time that will cause failure.
« Last Edit: May 25, 2012, 05:43:39 AM by K1CJS » Logged
W8JX
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Posts: 5755




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« Reply #11 on: May 24, 2012, 05:53:44 AM »

BTW, the instructions and other paperwork on the G7 is available on the DX Engineering website.  The antenna is supplied with an N connector, and the paperwork specifically tells you not to seal the connector area because that will cause the antenna to retain water, possibly causing corrosion over time that will cause failure.

Well most N connectors (Mil Spec anyway) are weatherproof and need no sealing.
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KC9NVP
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« Reply #12 on: May 24, 2012, 11:07:57 AM »

in a Mobile application, for distant contact, I would use a 5/8 wave in the middle of the roof.  For around town and close to the repeater, then 1/4 wave will work fine.  I have found the 5/8 wave is better for distant then 1/4 wave due to the difference in take off angle of the signals, which is great when traveling.  For my 2 meter home base setup, I am using Hy-gain collinear V-2 antenna (that I picked up used) at about 35 ft on my tower.  I can hit every repeater in the counties surround the county I live in, which is great since I do weather spotting and ARES.

73,

David
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W8JX
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« Reply #13 on: May 24, 2012, 09:27:01 PM »

The longer antenna is better for mobile for another reason. It is called capture area. At times you will find when using a HT with a short antenna that you can move a foot or two in various directions and signal can increase or decrease when on fringes. With a longer mobile vertical you span these "holes" better.
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KW6LA
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« Reply #14 on: May 24, 2012, 10:22:17 PM »

 Hustler G7............ and a larson 5/8 wave beats a 1/4 wave spike hands down for general use. You have to own them and use um to find out !
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