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Author Topic: 10m vertical  (Read 7834 times)
KJ4BCF
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« on: September 25, 2012, 05:56:34 AM »

Just wondering. With 10 meters open a bit now, what are the advantages of a vertical antenna? I have a homebrew dipole mounted just over the peak of my roof now(just getting back on the air after a few years hiatus), which I will be putting up higher as time permits.I've made contacts with Germany and Argentina, and the west coast with it in the last few days, though. Would a vertical make much difference for local contacts? Thanks
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WB2WIK
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« Reply #1 on: September 25, 2012, 09:31:31 AM »

Probably not a lot; but a horizontal antenna provides a gain advantage (in two directions) that a conventional vertical cannot.

I'd stick with the horizontal and get it higher if possible.

Of course, making it rigid enough to rotate, and rotating it, is better because that will give you coverage in areas a fixed dipole cannot.
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G0VKT
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« Reply #2 on: September 25, 2012, 09:46:23 AM »

Why not try it and see?

I have 102' doublet which is less than optimally installed. Who knows what the radiation pattern is! I built a homebrew end fed for 10m.
Sometimes it is up on the doublet by 2-3 S points, sometimes it is down depending on the ststion and location. But only done a few tests so far. I want to scale it for 15m and 20m.
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W5WSS
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« Reply #3 on: September 25, 2012, 09:52:04 AM »

The horizontal dipole benefits directly from height above ground with respect to pattern. Ideally, When the horiz. dipole is high enough the pattern will develop to it's fullest broadside radiation and directivity and least possible radiation off the ends of the wire direction.

Higher even more the antenna now doing as intended by the inventor within the broadside figure eight pattern will develop more major and more minor lobes of radiated power manifestation as a function of greater height. A real useful lobe manifests lower and lower towards the horizon as height is increased.

Rotating any horizontal directional antenna including an Aluminium tube dipole fills in the other area of the globe to be covered and almost always compared to a omni directional vertical does it better by scoring as a percentage of better results during very variable skywave conditions, admittedly anyone that likes a vertical and believes it to be superior can argue it is the vertical radiation.


A fixed orientation, horizontally radiating, wire dipole is very good. A rotateable dipole is excellent.

I always like the advantage of having more than one antenna per band such as an omni directional vertical and a rotateable dipole.

If you can, use both.  
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KJ4I
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« Reply #4 on: September 25, 2012, 11:09:36 AM »

Quote
Would a vertical make much difference for local contacts?

I'm assuming you mean local as within 100 miles or so from your location. I would think from my own experience that Vertical is the better option for local communications. In my area most people on 10 meters are using vertical ground planes and trying to work someone 25 or so miles away (consider variables) by cross polarization might work but its not going to be near as good as if you were both vertical or horizontal. In some cases you might not be able to work at all. As for DX It don't seem near as critical. I've had pretty good luck either way. Just experiment and see what happens but there are differences depending on many things. You just have to experiment and see what works. I agree with the previous post that having more than one type of antenna is a good option.
« Last Edit: September 25, 2012, 11:20:18 AM by KJ4I » Logged
KJ4BCF
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« Reply #5 on: September 25, 2012, 01:00:18 PM »

Thanks for the replies. Yes I was thinking vertical for 100 mile local. I think I'm going to put my dipole higher first, and put up a vertical next, hopefully soon! Any suggestions on it? Ground plane or...? What would be a good brand to look for in a production antenna, even though I would rather build my own? Thoughts or links to homebrew that works? A rotatable horizontal will be next. Thanks again...
« Last Edit: September 25, 2012, 01:02:08 PM by KJ4BCF » Logged
W5WSS
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« Reply #6 on: September 25, 2012, 04:27:02 PM »

you are welcome and have fun
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M6GOM
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« Reply #7 on: September 25, 2012, 04:50:23 PM »

I'd just get hold of a cheap 5/8 wave vertical for CB and retune it for 10m.
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RFRY
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« Reply #8 on: September 25, 2012, 04:53:58 PM »

Yes I was thinking vertical for 100 mile local

Depending on the heights of the transmit and receive antennas, the radiated power on that propagation path, terrain profiles, atmospheric conditions (K-factor), transmit and receive antenna patterns and orientations, receiver sensitivity, interference, etc etc -- then it might be possible for occasionally useful point-point, non-skywave, VHF reception over a 100-mile terrestrial path.

But just to note that omnidirectional FM broadcast stations with 100 kW of radiated power from transmit antenna heights of ~1,000 feet above average terrain produce a useful signal to very good FM receivers using Yagi antennas located 20-30 feet above the earth, 100 miles away, maybe only 50% of the time.
« Last Edit: September 25, 2012, 04:57:41 PM by RFRY » Logged
KC4MOP
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« Reply #9 on: September 26, 2012, 07:35:45 AM »

I'd just get hold of a cheap 5/8 wave vertical for CB and retune it for 10m.
That's what I'm using here. 5/8 wave. Lower TOA (take off angle) for possible DX and gain!!! Very manageable antenna for its size. Cheap too!
The horizontal wire is goodness too. Being that it is easier to get a 1/2 wavelength high, the horiz wire becomes directional and you are stuck in whatever direction you have it pointing.
A horiz Yagi becomes fun with gain and directional using a rotator.

Fred
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WX7G
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« Reply #10 on: September 26, 2012, 08:43:38 AM »

Yes I was thinking vertical for 100 mile local

Depending on the heights of the transmit and receive antennas, the radiated power on that propagation path, terrain profiles, atmospheric conditions (K-factor), transmit and receive antenna patterns and orientations, receiver sensitivity, interference, etc etc -- then it might be possible for occasionally useful point-point, non-skywave, VHF reception over a 100-mile terrestrial path.

But just to note that omnidirectional FM broadcast stations with 100 kW of radiated power from transmit antenna heights of ~1,000 feet above average terrain produce a useful signal to very good FM receivers using Yagi antennas located 20-30 feet above the earth, 100 miles away, maybe only 50% of the time.


Let's check the FM broadcast to 28 MHz SSB comparison.

Receive bandwidth of SSB is 3 kHz, broadcast FM is 75 kHz, SSB advantage is 14 dB
Receive antenna factor (20LOG(f1/f2), 98 and 28 MHz, 28 MHz advantage is 11 dB
Useful S/N ratio for FM is about 12 dB, for SSB it is lower, let's call it 3 dB
Range difference is 2:1, 28 MHz advantage is 6 dB (very rough estimate),  http://www.artscipub.com/simpleton/simp.range.html
Height difference 1000' vs 100', FM gets a 6 dB advantage (very rough estimate)
Terrestrial noise difference, FM advantage 4 dB

From 28 MHz SSB communication as compared to FM Broadcast, given the same antenna gain at both ends of the link and the same antenna heights, 28 MHz SSB requires 24 dB less power. The 100 kW FM becomes 400 watts SSB.

Given more time I would download a proper propagation analysis tool.

Conclusion: The terrestrial propagation range of FM broadcast under the conditions given and 28 MHz SSB are roughly equal.



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KA7NIQ
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« Reply #11 on: October 21, 2012, 08:33:48 AM »

Thanks for the replies. Yes I was thinking vertical for 100 mile local. I think I'm going to put my dipole higher first, and put up a vertical next, hopefully soon! Any suggestions on it? Ground plane or...? What would be a good brand to look for in a production antenna, even though I would rather build my own? Thoughts or links to homebrew that works? A rotatable horizontal will be next. Thanks again...
Yes, Look for a CB Antenna called a Starduster. It is a center fed vertical antenna, with 3 sloping radials. The feed line goes right up and into the support mast. This, the center feed, and the 3 sloping radials stop common mode currents on your feed line.
They are sold on Ebay, and made by an Italian Company called Sirio.

The 5/8 wave cb antennas would be my second choice, because they have radials.
I would stay away from Antron 99 and end fed fiberglass antennas, unless you like radiating coax and mast pipes ?

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VE3FMC
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« Reply #12 on: October 21, 2012, 07:12:48 PM »

I recently mounted a very old 5/8 wave ground plane at 25 feet. This antenna is close to 40 years old. My late father had it mounted on the old 2 story farm house back in 1978 or 1979 when he was first licensed. He used it for 10 meter phone after he got his first endorsement (Licensing was totally different back then in Canada)

When I first put it together I mounted it on a tripod 5 feet off the ground to check the SWR. I made a contact to Austria on JT65 with 15 watts with the antenna 5 feet off the ground.

I have a 2 element triband at 33 feet. There are times when the ground plane is better than the beam.

I have not talked to any locally on 10 meters with it as not too many guys around get on 10 meters locally to rag chew (not sure why, they just don't)

I would say it is nice to have both options when it comes to 10 meters. I wish I could get mine up higher but I can't do that.

I am going to replace it with a Hy Gain 14AVQ as soon as I pick that antenna up. Same height, just need to add radials for the 4 bands. It will be interesting to see how it performs at 25 feet off the ground.
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KB5UBI
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« Reply #13 on: October 21, 2012, 07:24:34 PM »

I like a vertical on 10 meters for DX, but for local chats it will suffer from cross polarization loss because most HAMs are using horizontal polarization on 10 meters.

For 10 meter DX, my Butternut HF6V out performs my three element beam at 35 feet.
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W5DXP
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« Reply #14 on: October 21, 2012, 07:27:44 PM »

Just wondering. With 10 meters open a bit now, what are the advantages of a vertical antenna?

What makes a very good 10m antenna is a rotatable hamstick dipole at a height of 20-30 feet. It has about 6.5dBi gain at a TOA of 19 degrees.

For 10 meter DX, my Butternut HF6V out performs my three element beam at 35 feet.

Is your three element beam designed for 10m?Smiley
« Last Edit: October 21, 2012, 07:30:59 PM by W5DXP » Logged

73, Cecil, www.w5dxp.com
The purpose of an antenna tuner is to increase the current through the radiation resistance at the antenna to the maximum available magnitude resulting in a radiated power of I2(RRAD) from the antenna.
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