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Author Topic: Wilson 1000 Problems On Hyundai Elantra  (Read 1529 times)
KV4BL
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Posts: 77




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« on: September 21, 2003, 11:04:59 PM »

I hope someone can help me with a very frustrating problem.  First off, let me say that (at the risk of a few flames) I have a CB mobile with WX receive in my 2000 Elantra, alongside my IC-2800.  The CB is far better for getting info on road conditions and in a real disaster, certainly expands my communications horizons on a local level.  Now to the problem.  I just replaced a base loaded Hustler 27 MHz antenna that was hole mounted in the center of my trunk with a W-1000.  The Wilson has a SWR of (plus or minus) around 2 to 1.   It does not vary with regard to which channel and this is usually indicative of a problem other than length / tuning.  The shop I bought it from tried everything from hardwiring a wire jumper from the body to the trunk lid to insure grounding, to changing coils, whips, and cable harness, all with no results.  My trunk is definitely metal, as is the rest of the car.  Wilson says that the car may just be too small to give their antenna an adequate ground plane.  While the Elantra is not a large car, I have a problem believing that it doesn't have enough metal for a decent ground plane.  A Ford Aspire, maybe...  Oh yeah, we also checked to make sure the grounding star inside of the trunk makes contact through the paint.   Any ideas that might let me use this antenna with a better SWR?Thanks in advance.73,      Ray  KV4BLPS for what it's worth, the previously installed Hustler had a flat (almost no needle movement) SWR across all 40 channels but was not a good radiator as I have heard others describe some Hustler mobile antennas on hf.
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KZ9G
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Posts: 36




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« Reply #1 on: September 22, 2003, 12:31:09 AM »

I would say a 2:1 match isn't all that bad, although not quite what you're used to.  If the CB can handle the slight mismatch, don't worry about it.

The basic question is it's efficiency as compared to the Hustler.  Does it actually perform better that the original Hustler?  I'd like to think they're close to being equal in performance, mismatch or not.  That is, if the Hustler was a center loaded 4 to 5 foot model, or even the 7 to 8 foot ham model with the 54 in. mast, the performance between them and the Wilson would be hard to distingush.

Good Luck.  
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N3BIF
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Posts: 1190




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« Reply #2 on: September 22, 2003, 09:31:10 AM »

  Test the Wilson on a bigger car and see what happens to your reading. I would agree though that if it works sufficiently that SWR is no big deal
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K0BG
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« Reply #3 on: September 22, 2003, 10:06:34 AM »

Either buy or find some nearby ham who has an antenna analyzer and find out where it is resonant. I'd bet it is not properly tuned.

As for the groundplane size, at 28 Mhz, the difference beween a VW beetle and a Grayhound is all but moot.

Alan, KØBG
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K5LXP
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« Reply #4 on: September 22, 2003, 01:31:19 PM »

Didn't see this mentioned- check the coax, especially the ground integrity.  As mentioned previously, an antenna analyzer will speak volumes.

Mark K5LXP
Albuquerque, NM
k5lxp@arrl.net
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N8IWK
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Posts: 80




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« Reply #5 on: September 22, 2003, 02:11:44 PM »

I've experienced similar problems with my 1000 on a minivan. I was using a shortened K-40 for 10 meter operation, decided to try a Wilson 1000 because of it's claims to outperform the K-40. I have not been able to get near the low SWR reading I was getting with the K-40. Both antennas are magnet mounted and have used the same mounting location on the vehicle, even after making several attempts to shorten the Wilson whip still no significant improvements in SWR readings. And performance is not as much better maybe even worse than the K-40.
I'd be interested in hearing from others how much the whip needs to be trimmed on the Wilsopn 100 for use on 10 meters.
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N8IWK
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Posts: 80




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« Reply #6 on: September 22, 2003, 02:12:41 PM »

I've experienced similar problems with my 1000 on a minivan. I was using a shortened K-40 for 10 meter operation, decided to try a Wilson 1000 because of it's claims to outperform the K-40. I have not been able to get near the low SWR reading I was getting with the K-40. Both antennas are magnet mounted and have used the same mounting location on the vehicle, even after making several attempts to shorten the Wilson whip still no significant improvements in SWR readings. And performance is not as much better maybe even worse than the K-40.
I'd be interested in hearing from others how much the whip needs to be trimmed on the Wilson 1000 for use on 10 meters.
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K0BG
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« Reply #7 on: September 22, 2003, 02:24:59 PM »

The results from using an SWR bridge or wattmeter to "tune" an antenna has more to do with luck than is does theory.

The MFJ259B is as good as any inexpensive antenna analyzer. At between $200 and $260 depending on where you buy it, it is a godsend when working with any antenna or antenna system. It should be a requisite for any ham shack.

Alan, KØBG
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N6AJR
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Posts: 9910




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« Reply #8 on: September 23, 2003, 12:11:28 AM »

not true, I say,  if you check the swr at the low end , in the middle and high end of the band, you will find the swr is higher  at one end than the other and by comparing to the middle you can figure which way to go.  

 lets say at a given band from low to high end it reads swr of 1, 2, 3, then the entire antenna is too long as it goes up with the shorter freq signals.

 if it goes  3, 2, 1, then the antenna is too short and as the freq goes up (shorter wavelength)it matches better.  

if it goes 2, 1, 2 then it is good in the middle and not very broad banded.  

I hope this helps.  by the way, go back to the old antenna if it works better...
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K0BG
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« Reply #9 on: September 23, 2003, 10:04:20 AM »

Tom, N6AJR, think about this for a moment. If 2:1 is the lowest VSWR you can achieve using a SWR bridge, is the input impedance 25 ohms or 100 ohms? Is it resistive or reactive? An SWR bridge will not give you those figures. An antenna analyzer will.

Alan, KØBG
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KT8K
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Posts: 1490




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« Reply #10 on: September 23, 2003, 04:06:09 PM »

You could undoubtedly find a local ham through a club in your area who has an antenna analyzer and would help you improve your SWR.  2:1 isn't bad, though, and indicates that you aren't losing all your power to loss of some kind.  That's good.

You have one club within 20 miles and five within 50 miles of you.  Check them out.  Contact info at: http://www.arrl.org/FandES/field/club/clubsearch.phtml?zip=29073&dist=50.
Good luck es 73 de kt8k - Tim
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N6AJR
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Posts: 9910




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« Reply #11 on: September 23, 2003, 07:47:18 PM »

true but if its too short you and inductance and it goes closer to 50 ohms Impedance, and if its too long you shorten it a bit makeing it closer to 50 ohms and the the match is better..

 I find most folks having cb problems with swr, have the radio sitting on the sat running a mag mount and a ciggerett lighter power plug.  

I tell them to mount the radio, put on a GOOD ground from the chassis to the rig, wire it direct to the battery, and put on an antenna that has a ground element to it.  

this usually takes care of the rf feedback loops they develope if you don't.. but thats just my experiance..

 good dx  73  tom N6AJR
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AA4PB
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Posts: 12890




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« Reply #12 on: September 23, 2003, 09:39:10 PM »

Tom, you are assuming that the antenna presents a 50 ohm load at resonance, which may or may not be so. An antenna can be resonant and present a 100 ohm or a 1000 ohm load or anything else. Take an end-fed 1/2-wave wire. It is resonant but the load impedance is on the order of perhaps 2000 ohms and the SWR is very high when fed with 50 ohm cable. There are two pieces to the puzzle: One is to make the antenna resonant (no inductance, only resistance at the feed point). You can't do that reliably with only an SWR bridge. The other is to match the feed impedance to the feed line (1:1 SWR).
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N6AJR
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Posts: 9910




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« Reply #13 on: September 26, 2003, 12:05:31 AM »

strange, I have used a swr bridge to tune antennas for years.. now I have a mfj 259 also, but still can tune an antenna with a swr meter.  an antenna is resonant SOMEWHERE, and you go up and down till you find the resonant point.  

if its too high in freq, ( like a 10 meter antenna that is resonant at 30 mhz,) it is to short and needs to be longer...make it too long (resonant at 26 mhz ) and you need to shorten it a bit to make resonant at 28.500, where I would shoot for on 10 meters.  

I prefer a dual cross needle meter, but the old set and check will work.  the mfj 259 makes it easier.  

You will probably know enough about the antenna to be in the ball park when you start.  lets say you are making a dipole for this  28.5 mhz on 10 meters, I would start with each leg of the dipole about 8 feet and 6 inches long, (quarter wave on a steel cb whip ,1/4 wave is about 102 inches from radio shack, =8 feet six inches) and then shorten it to your best swr at 28.5..  

easy and simple, and it works for me...

tom N6AJR
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