Any one here build one of these antennas???????? My question on this antenna is that the adjustment ring that goes around the antenna for SWR adjustment is attached to the ground radials. Wouldn't this cause a short???????? Please take a look and let me know, or is this is where the gain is accomplished??
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Danny Rogers...........Wile E. Coyote..............Unit 505 Land of Enchantment, New Mexico
11 Meter Vertical Gain Antenna
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Wile E. Coyote
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- Real Name: Danny Rogers
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Wile E. Coyote
- Donor
- Posts: 269
- Joined: January 28th, 2007, 9:26 am
- Handle: unit 505 Wile E. Coyote
- Real Name: Danny Rogers
- Antenna: 55' high omni directional fiberglass
- Radio: Several, depending who I am talking to
- Contact:
Wile E. Coyote wrote:Any one here build one of these antennas???????? My question on this antenna is that the adjustment ring that goes around the antenna for SWR adjustment is attached to the ground radials. Wouldn't this cause a short???????? Please take a look and let me know, or is this is where the gain is accomplished??
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Danny Rogers...........Wile E. Coyote..............Unit 505 Land of Enchantment, New Mexico
Hey antenna guru's.......... Still wondering if anyone has any information on this type of antenna before I try to set one of these up????????? Or, if you have any suggestions on this antenna.
Thanks,
Danny Rogers........Wile E. Coyote........Unit 505 Land of Enchantment, New Mexico
-
Wile E. Coyote
- Donor
- Posts: 269
- Joined: January 28th, 2007, 9:26 am
- Handle: unit 505 Wile E. Coyote
- Real Name: Danny Rogers
- Antenna: 55' high omni directional fiberglass
- Radio: Several, depending who I am talking to
- Contact:
147 express wrote:it is like to maco v5000 antenna an it will not short to adjust the swr is to adjust the length of the antenna the ring is to get the same swr on ch1 an 40 an i have mine set a 6" around the ring an it is fine all the way around
147, Thanks, I needed that information and will get started in the am on making this antenna so that I can set up a base station.
By the way, I hope you got the information on how to post a new question or topic.
Danny Rogers........Wile E. Coyote.........Unit 505 Land of Enchantment, New Mexico
-
Wile E. Coyote
- Donor
- Posts: 269
- Joined: January 28th, 2007, 9:26 am
- Handle: unit 505 Wile E. Coyote
- Real Name: Danny Rogers
- Antenna: 55' high omni directional fiberglass
- Radio: Several, depending who I am talking to
- Contact:
Got it Thanks...........
Danny Rogers.......Wile E. Coyote
Danny Rogers.......Wile E. Coyote
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'Doc
What appears to be a direct 'DC' short really isn't, or doesn't have to be, at 'AC'. So, that 'ring' when it's adjusted correctly, will allow the RF (which is AC) signal to passed with no problem. That 'ring' is an impedance matching circuit for a particular range/band of frequencies, does the same thing as a 'tuner' would do, a sort of RF transformer. That 'ring'/tuner/transformer is variable, you can change it by where the center conductor of that coax is 'tapped' along that ring. All that it does is change impedances.
Any gain is a function of the length of the antenna, some lengths have gain in relation to other lengths. That particular antenna is a '5/8' wave length long. A typical 5/8 wave antenna has a fair amount of gain over a 1/4 wave, and slightly more gain than a 1/2 wave length antenna. 'Gain' is accomplished by changing the radiation pattern, redirecting where that radiated signal goes. A very general/rough example of this 'redirecting' is the 'shape' of that signal radiated. A 1/4 wave antenna produces a 'shape' that looks like a ball. A 1/2 wave antenna's radiation pattern shape is more like a donut. A 5/8 wave's 'shape' is like a flatter donut, or a pancake with a hole in the middle of it. No antenna 'makes' more signal to radiate, it just sort of changes the shape of the radiation pattern,taking radiation from one place and moving it some place else. That 5/8 antenna sort of moves some of the over head radiation down towards the horizon, a 'flatter' 'ball' pattern. Lots of things affect that 'shape', so none of them are exactly 'perfect' or always the same. Not a very good description of what's happening, but it's close, sort of, and can give you a general idea of where 'gain' as applied to antennas, comes from. Antennas are sort of like the nozzle on the end of a garden hose. It distributes things in a sort of pattern. The one doing the squirting has to select the 'right' pattern for what he wants to do. That sort of applies to polarization too. One nozzle shape makes a certain pattern when it's pointed horizontally. If you point it straight up, that same setting makes a different pattern. May or may not get the water as far from the nozzle, but it'll make it go all around the nozzle rather than in just one direction. (Talk about a bad analogy!
)
Oh well, that'll get you to the ball park, still won't find your seat though.
- 'Doc
Any gain is a function of the length of the antenna, some lengths have gain in relation to other lengths. That particular antenna is a '5/8' wave length long. A typical 5/8 wave antenna has a fair amount of gain over a 1/4 wave, and slightly more gain than a 1/2 wave length antenna. 'Gain' is accomplished by changing the radiation pattern, redirecting where that radiated signal goes. A very general/rough example of this 'redirecting' is the 'shape' of that signal radiated. A 1/4 wave antenna produces a 'shape' that looks like a ball. A 1/2 wave antenna's radiation pattern shape is more like a donut. A 5/8 wave's 'shape' is like a flatter donut, or a pancake with a hole in the middle of it. No antenna 'makes' more signal to radiate, it just sort of changes the shape of the radiation pattern,taking radiation from one place and moving it some place else. That 5/8 antenna sort of moves some of the over head radiation down towards the horizon, a 'flatter' 'ball' pattern. Lots of things affect that 'shape', so none of them are exactly 'perfect' or always the same. Not a very good description of what's happening, but it's close, sort of, and can give you a general idea of where 'gain' as applied to antennas, comes from. Antennas are sort of like the nozzle on the end of a garden hose. It distributes things in a sort of pattern. The one doing the squirting has to select the 'right' pattern for what he wants to do. That sort of applies to polarization too. One nozzle shape makes a certain pattern when it's pointed horizontally. If you point it straight up, that same setting makes a different pattern. May or may not get the water as far from the nozzle, but it'll make it go all around the nozzle rather than in just one direction. (Talk about a bad analogy!
)Oh well, that'll get you to the ball park, still won't find your seat though.
- 'Doc
