Just curious... I've noticed that in the rain, and only in the rain, my antenna vibrates somewhat odd... It sort of resonates about a point about 7 or 8 inches from the end (i.e. when the top part flexes forward, the bottom part flaxes backwards). I would assume that this has something to do with the resonant frequency of the antenna and the air flowing past it, kind of like what happened to the Tacoma Narrows bridge, but on a much smaller scale. It only does this when it's raining out... I remember my 97 did the same thing, and after a few months, it actually started to vibrate something on that side.... sounded like something fluttering in the breeze or something... Has anyone else noticed this happening? Does anyone know how to prevent this phenomenon? I know that My Ranger did it, and my other F-150 did it, but my Explorer has a rubber boot that goes about 1/2 way up the antenna... could that be just to prevent this from happening? Thoughts, comments, suggestions appreciated....

-Joe-

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98 Explorer (Lemon Law Case in Progress)

'00 F-150, X-cab, 4x4, Lariat, Off-road, Trailer Tow, Holandia Sunroof, built 11/99 picked up 10/00!Clear Corners, Manik Stainless Steel 1-piece brush guard, Custom CB wiring, Uniden PC76-XLW CB radio with K-40 Magna-Mount antenna (for now), 1 set of 165 watt KC Daylighters (for now... more on the way) Custom switch mounting plate and overhead console, Bully Stainless Steel Trailer hitch drawbarw/ 2" stainless steel ball.
List of planned mods: Clear tails, torsion bar tweak, bug deflector, spray in liner, and a tonneau of some sort...

93 Probe GT teal, OE rims painted to match, bone stock drivetrain.

 

Mine does it also. During rain and about
35mph and faster. It doesn't appear to be a problem at this point.

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2000 XLT S/C 5.4 Oxford White - 3.55 LS - Dark Graphite Captains Chairs - Towing Package - Sport Package - P275-60-R17 - In Dash CD - Slider - Duraliner - Sport Decals removed before I would take delivery

 

Mine does it too. Starts about 35-40mph. Funny you should mention it. It was bugging me just the other day, but I can't remember if it was raining or not.

The first time I saw it was after an ice storm. It was fun seeing it shake all the ice off. Ford's entertainng antennas should've been put on the drivers side so your eyes could stay closer to the road

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White 97 XLT SC 4.6, 4X4, 3.55ls, door cracks, tow pkg, long bed, Rhino liner, Owens running boards

 

Mine Does it too! Only in the rain though.

 

Mine does it also.
If you notice the gmc engineers have figuered out how to fix this, their antenna seem to have a wire wrapped around them, under the outer shell. This prevents them from doing this.

 

As far as I know the wire wrap does not stop the antenna from vibrating and getting a node point. Thats the point that looks like it doesnt move. The wire is for better tuning of radio waves probably.
As you speed up the node point will move on the antenna. If you go fast enough and the metal is elastic enough you will see two points. When your going slow the node point is at the tip of you antenna or off of the antenna above it.
I do not believe you will have any problems from the antenna. Harmonic loading and failures usually happen in larger objects like bridges and airplane wings.

 

back in 96 i asked a chevy salesguy why the antenna was wrapped like it is and he proudly explained that it was to reduce wind drag on the antenna and the associated noise. could be something to do with the cancelling potential harmonic frequencies with would cause a vibrating antenna

not that i have the real answer....

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2001 F-150 5.4L Supercab XLT 4x4 (silver)

Options:

• tow package
• power adjustable pedals (for the short pregnant wife, see below)
• carpet delete
• Speedliner
• law enforcement scanner
• CB w/ PA
• Graco infant car seat (not in use yet, see below)

Infant Male
ordered: August 2000
scheduled delivery: 7 June 2001

Options:

 

I thought the wire wrap was the antenna itself, and the fiberglass rod is there for support. The wire being coiled around an insulator makes the antenna act electrically longer than the support length.
That guy who abandoned his car on the T.N. bridge, did you know his car had piston slap, a squeaky pitman arm, door cracks, roof cracks, and the dealer said it needed a transmission flush, a motor flush, and a complete pocketbook flush. So he left it there and walked.

 

<grin> This is actually a finely-engineered Ford feature, and I don't know why you guys haven't figured it out. At speeds greater than 35mph, the antenna is designed to vibrate faster with speed, thereby producing an additional 6 amps of current to assist your alternator. It's mounted on the passenger side so the driver won't ever reach out and touch it, saving him from a terrible shock.

 

Hmmmm... Interesting theory Sundog. I'll have my wife stick her hand out the window at about 40 mph and see if your theory holds water (no point in the driver taking such a risk ... somebody could get hurt).

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1999 Lariat Super Cab, S.B. 5.4L, 3.55 LS
and every option but the leaky slider window.
Bright red w/ gold 2-tone, Leather Captain's Chairs
Mods: Duraliner bedliner, Bugflector II, Hide-a-hooks.
& a leeetle chrome tip on the exhaust.

 

I noticed mine doing that the other day. It only does it when it raining. Weird. And Ford does know about the "spiral wrapped" antennas. Look at any late model Taurus.

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2000 F150 XLT 4x4 Short Bed. Amazon Green, 5.4L, SuperCab, ORP, Tow Package, Sliding Rear Window, Electronic Shift, Keyless Entry, LT265-70-17 Tires, Clarion Pro Audio, Herculiner Bedliner, Air Silencer Removed.

1994 SVT Mustang Cobra. #1032 of 6009. Black coupe with black leather int., 3.73 rear, Bassani Exhaust, Aluminum D/S, Bridgestone RE-71 255-45-ZR17

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