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Author Topic: remote antenna tuners  (Read 1745 times)
WB9JOX
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Posts: 103




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« on: August 27, 2012, 10:17:22 PM »

Want to use remote antenna tuner with my Zero 5 ground plane. Would like to run no more than 500 watts.Also wonder if there would be much benifit or gain ,compared to using my manual tuner.Guess what Im asking is it worth the expense for small amount of gain.Any input appreciated.
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K2OWK
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Posts: 1077




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« Reply #1 on: August 28, 2012, 01:06:35 AM »

The tuner will not increase the antenna gain. It will just give you a wider bandwidth. The ability to operate most bands with the one antenna. Auto tuning is a great convenience, your antenna is tunes at the push of a button, and most of the autotuners have memory for the bands that are tuned to.

73s

K2OWK
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NA4IT
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Posts: 893


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« Reply #2 on: August 28, 2012, 04:27:14 AM »

You could do the same thing with a 43 foot vertical (wire or tubing), a radial field, and a tuner at the base of the antenna. Really is the "ideal" way to do it.
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KC4MOP
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Posts: 764




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« Reply #3 on: August 28, 2012, 04:42:27 AM »

You could do the same thing with a 43 foot vertical (wire or tubing), a radial field, and a tuner at the base of the antenna. Really is the "ideal" way to do it.
NA4IT has a very good approach. A lot cheaper to build the antenna and use the saved money for an MFJ high power remote tuner. (MFJ998RT??) about $760?? Full legal limit tuner that works well on the 43 footer. You might need an external coil for 160M.
If I were in the market, I would buy the DX Engineering 43 footer without the balun and do what NA4IT mentioned. Or fabricate something that is 43 feet tall and insulated from the ground and you have arrived.
DX Engineering has insulated tilt-over base for verticals and MFJ has a better solution that is cheaper for a tilt-over base.
Nothing wrong with Zero-Five. Are you going to try to put 5KW into it??

Fred
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WB9JOX
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Posts: 103




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« Reply #4 on: August 28, 2012, 07:25:42 AM »

I appreciate all the answers to my question.I agree the 43 foot antenna would be much better and not as costly.I just dont have ideal location in the yard.I have ground plane on the roof and works pretty good.Thanks for the input comments saved me money.Thank all of you.
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K5KNE
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Posts: 65




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« Reply #5 on: August 30, 2012, 03:20:49 PM »

I recommend you spend money on antennas instead of tuners.  The suggestions above are good. You should consider some loading in a vertial antenna if getting 40'+ is problem.

You might consider a fiberglass pole and if it is too short wrap a few turns in the wire running up the pole.  Also, an antenna analyzer would be a big help.

Good Luck   K5KNE
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W5WSS
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Posts: 1783




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« Reply #6 on: August 30, 2012, 04:24:23 PM »

All of the vertical lengths used with the proper rated network tuner and 1:1 current choke both being located together at the antenna base feed point, work fairly well.
Install the 1:1 current balun between the network output terminal and the antenna base.
Not all antenna lengths are optimal to service all the ham bands. For reasonable utility one should seriously consider 5 bands as the best compromise for low enough TOA when pursuing long distance skywave.
I expect TOA to be OK when the antenna maximum total length does not exceed 5/8 wavelength for the highest band of interest and not shorter than 1/4 wave length for the lowest band. Or top hat loading to compensate if the antenna length must be reduced .Beware though that wherever The antenna will be close to an end fed half wave "you will need to determine where that occurs based on your specific installation' but end fed half waves inherently present high impedance and causes stress to an auto tuner.
I prefer to choose a shorter length somewhere around 22-28 ft as I am not interested in low band dx. or am I worried about raw antenna gain maximums.
In this case the 22 ft version and 15m a little stressful but otherwise passes my criteria for usable for skywave longer distance dx.
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W5WSS
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Posts: 1783




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« Reply #7 on: August 30, 2012, 04:42:01 PM »

That previous post did not address the multi band counterpoise challenges as so much interaction needs to be considered and analysed as to whether or not it is functioning as intended in theory.
The multi band counterpoise has eluded proper attention and warrants a series of double checks to verify the effectiveness of the design goal which is antenna completion.
The builder needs to be aware of the multi facet function of a multi band counterpoise with a great emphasis on common mode abatement and the ill effects it poses to the system as a whole.
The 1:1 current choke is an aid and more in antenna to counterpoise balance because the system works best when measures are provided to interconnect the two parts of the whole system.
When properly implemented maximum system field strengths can be realised from either both elevated or ground contact or subterranean radial counterpoise systems but never assume so.
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KC4MOP
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Posts: 764




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« Reply #8 on: August 31, 2012, 03:43:40 AM »

To W5WSS:
My somewhat fair understanding about TOA is that it is the 5/8 wavelength that gives you the 16 degree TOA for long DX. 5/8 wave is not resonant and will always need a tuning network at the base of the vertical, usually an adjustable coil in series with the feed line.
When radials are just laying on the ground there is no resonance to be concerned about. Elevated radials, YES. They can be a hazard to people and animals. 10 feet off the ground is minimal height.
If a Ham has extreme limited space for a minimum of 40 radials 100 feet long; then he should concentrate the radials with 40-50 short radials near the base especially and get longer radials out using longer lengths wherever he can.
It seems that the myth has been broken that 120 radials 120 feet long has been broken and 40-60 radials is enough. It was a strict requirement of the FCC to have some guarantee for the broadcaster to have good coverage no matter what the ground conductivity was. Broadcasters that had excellent ground conductivity would usually have to reduce their power to meet the specs from the FCC to prevent interference to adjacent stations. I'm guessing that the chief engineer still has to walk the radials and take RF field measurements as part of maintenance of the station.


Fred
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W5WSS
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Posts: 1783




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« Reply #9 on: September 01, 2012, 08:21:03 AM »

Hello Fred, The 43 ft version is  5/8 wavelength on 40m. and 1.25 wavelength up on 10m where on 10m that physical length(43ft concentrates manifested power at  too high an angle for my preference. That is not to say that the 1.25 wavelength vertical does not make contacts but when we attempt to quantify the averaged angle of concentrated Field strength radiated,It is on a sliding scale lowest where it is a 5/8 wave and highest when it is a 1.25 wavelength, we already know it is mostly towards the zenith, manifested Field strength is fairly high when greater than 3/4 wavelength and longer vertical antennas are pressed into service. We have tuners and baluns that make it possible to use these longer versions but in my opinion I would rather not press the 1.25 wavelength vertical into service when I could use a shorter more effective length instead.
Yes with a greater than 3/4 wavelength vertical antenna length there remains some lessor measured Field strength  manifested power at the lower angles but greatly reduced compared to it's own self at the higher angles respectively. The polar pattern favors upward at a much higher percentage yielding excellent close in skywave reception and poor longer skywave results.
I like a shorter vertical that is 5/8 wave or thereabouts on 10m while being no shorter than a 1/4 on the lowest band when Dx skywave longer distances is my design goal. There is some debate but it is generally understood that a 5/8 wave develops and manifests angel wings or a secondary lobe that is useful offering a utility to the user in the form of better compatibility with skywave variables but compared to a quarter wave that is an gray area of ongoing debate as to whether or not the raw gain does more work.
In order to accomplish such a design parameter one must not assume that a radial set of counterpoise system automatically allows lowest Tao to be manifest because the interaction of the second half of the system needs to be verified.
Fred I hope that helps 73 and happy Labor day weekend. 73
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