Why the spiral pattern on Radio Antennae and Grid on Windshield?

Page 2 of 2  


My 2004 Dodge truck seems to be wound, like with stainless steel foil??
Al
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That's cut

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
this spiral is there to improve gas mileage. Studies indicate a 20% increase in EPA gas mileage rating when a spiral antenna is used.
terry

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
How can a little radio antenna improve gas mileage that much? If it has that much effect then how much would you improve the mileage if you removed it all together?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
it is simple.... the antenna spiral creates a vortex in a manner such that it creates a low pressure around the front of the vehicle. this low pressure effect is like the vehicle always driving or being pulled into a vacuum. And this take less gas to move the vehicle along and is similar to a draft when one follows real close behind a big truck on the highway.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If it was that simple to increase gas mileage, why don't cars have several of these. And if a small piece of wire has that much effect on a large vehicle, why are airplane wings so big?
If the vaccuum I could create behind my motorcycle is to be looked at, I would pull a tractor trailer off the road when I passed by.
Sounds like a lot of horse manure to me. An AWFUL LOT of horse manure.
I am sure there is a valid reason for the spiral, but I don't think it has anything to do with gas mileage. If it did, all the manufacturers would be using it. And you would find someone on the tube seling them and making a mint. Have you seen that? I didn't think so!!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just think what that antenna, a fuel line magnet, and a tornado would do for your mileage! You would probably have to drain fuel out of your tank to keep it from overflowing.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The spiral reduces noise created by air rushing across it. If you don't belive it, run a piece of tape lengthwise to the antenna and drive at 65 mph. It will have considerable noise. STOVEBOLT (Nickname for 1930's Chevy)
On Mon, 31 Oct 2005 02:19:41 GMT, "Yammie"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mitsu huh. Figures ...
I've got a bunch of the others around here as spares. They are all ground. The easy way to tell is to look at the base area, the grind stops about an inch above the adapter. On average we coated 30,000 a day for each of the big three. Hated the damn things because they were racked 20 per row on a 3 row rack. You had to get between the rows and coat the adapters, then down the shafts, then spin them while coating from the outside. Too much powder and you hid the details and had a "drip" on the end. Not enough and you got textured finish.
--
Steve Williams

"Steve Mackie" < snipped-for-privacy@ns.sympatico.ca> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mine is also a wire wrap, just went down and looked at it. I took a picture, but my camera sucks so it didn't take well. I can tell it's a wire wrap because it's starting to seperate in one spot and in another there is a kink in the wire. I also looked at the two cars parked next to me, a late model Buick and a late 90's Caravan. The Caravan appeared to be a wire as well and the Buick's was identical to mine. You really can't get much more common than a mid-90's W-Body GM, so it's safe to say there is A LOT of wire wrapped antennas "whipping in the wind."
Steve

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

And I believe the ones top-center on the window are there as a sunscreen, since you can't get a visor over there. You don't often need to look through that portion of the window, so they block out the sun.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The spiral is to reduce wind noise???? Reducing the smoothness of a wind-exposed surface hardly reduces the wind noise---in fact it would have the opposite effect.
The spiral is indeed for the purpose of increasing the effective length of the antenna. It's a common practice to use a coil to reduce the physical size of an antenna without decreasing its effective length.
As for the dots, I have no idea. My guess would be to act as a sunscreen.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
sean snipped-for-privacy@yahoo.com (Sean Elkins) wrote:

GULP--the sound of me eating my words. Looks like I was wrong about the wind noise, although in my meager defense that does seem counter-intuitive that roughing up the surface would cut wind noise. I thought the more streamlined an object the less air it would displace?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sean Elkins wrote:

From an Engineering stand point.... The Spiral wrap induces Eddy Currents
which reduces the wind drag force on the antenna to minimize vibrational
whipping action.... This and the German periscope spiral function
are notorious educational discussions at Automotive Engr Seminars offered
in Detroit in the fall.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robert Ball wrote:

The spiral wrap on the car antenna is there to reduce wind drag &
stop antenna 'whip motion'. The German's used this feature on WW2
submarine periscopes to stabilize 'periscope viewing'. With the spiral
wrap, antennas could be made smaller diameter & still resist wind/water force
without bending nor vibrating much in the breeze.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

refineries
Andreas
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Most of the above-mentioned apply, especially the eddy current and vibration, but the primary purpose of the spiral is to prevent/avoid wind resonance (re: Tacoma State Bridge). If you have ever driven in sleet/rain and have the spiral-wound antenna caked in ice, the antenna will vibrate, depending on our speed, initially with one node, then two nodes, then three if you are crazy enough to drive that fast in that weather.
Franko

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.