I am beyond perplexed with trying to solve my antenna problem. I had co phased Wilson 4 ft whips on my pickup and they worked perfect for 4 yrs till one antenna got loose and stripped out the bottom fitting. I replaced the bad antenna and could not get it to resonate in the 11 meter band. So I then replaced the mounts and the coax harness. Still is resonating at 28.130. When I test either antenna separately , still no luck. I pulled the mounts and ground off any paint for a better ground and no change? Anyone have any insite or ideas?
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WILSON CO-PHASED 4 ft WHIP PROBLEM
- Thread starter tunedandloaded
- Start date
I disconnected the harness and tested them individually with a separate piece of 50 ohm coax.
Do both antennas test good individually on the single 50 ohm coax?
If yes, then are you sure your dual coax is 75 ohm cable? it should be stamped on the cable about every 2 ft. what type of coax it is.
Did the original antenna still tune up to 11 meters on a 50 ohm piece of coax?
Are you relying on the radio's SWR meter or do you have an external SWR meter? Have you checked the SWR with both? is their much difference between the 2?
If yes, then are you sure your dual coax is 75 ohm cable? it should be stamped on the cable about every 2 ft. what type of coax it is.
Did the original antenna still tune up to 11 meters on a 50 ohm piece of coax?
Are you relying on the radio's SWR meter or do you have an external SWR meter? Have you checked the SWR with both? is their much difference between the 2?
No the separate antennas do not test good on separate piece of 50 ohm coax. They resonate out of the 11 meter band. I'm using a MFJ 259 analyzer
Your problem is perplexing. Here some more questions to give us more insight on your problem.
Did you ever measure your antennas before the 1 went bad with an analyzer, and if so did it resonate on the CB band?
What reading is your analyzer at 27.200 MHz? with and without co-phased 75 ohm coax.
The Wilson whip you are using, is it a 4 ft. fiberglass with a tunable tip?
If you had a D.C. ground problem, normally you wouldn't find a good match any where. If your analyzer is showing a resonant point of 28.130 MHz, then your antenna needs to be lengthened.
Did you ever measure your antennas before the 1 went bad with an analyzer, and if so did it resonate on the CB band?
What reading is your analyzer at 27.200 MHz? with and without co-phased 75 ohm coax.
The Wilson whip you are using, is it a 4 ft. fiberglass with a tunable tip?
If you had a D.C. ground problem, normally you wouldn't find a good match any where. If your analyzer is showing a resonant point of 28.130 MHz, then your antenna needs to be lengthened.
Yes very perplexing, the antennas had a flat match throughout the entire 11 meter before the one antenna went bad. Above 3:1 both with and without co phased at 27.200. Yes they are the Wilson 4 ft with tunable tip. My only thought is to add a spring to the antennas even though they were fine before. I even changed the batteries in the analyzer because I thought I might be getting false readings.
[QUOunedandloaded, post: 523464, member: 19989"]Yes I thought that but works great on my base antennas.[/QUOTE]
Each antenna should be electrically identical and resonant at a lower frequency than the intended freq once they are phased. Try taking an ohm meter between antenna mount and battery ground to see what you come up with. Should read zero ohms. Once there you can check resonance
Each antenna should be electrically identical and resonant at a lower frequency than the intended freq once they are phased. Try taking an ohm meter between antenna mount and battery ground to see what you come up with. Should read zero ohms. Once there you can check resonance
When you tune them individually with a piece of 50 ohm cable they will be electrically too short and resonate at a higher frequency when you reattach the phasing harness.