Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old October 11th 17, 07:38 AM posted to sci.electronics.repair
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Default car antenna with serpent

The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?

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Old October 11th 17, 08:46 AM posted to sci.electronics.repair
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micky wrote:

The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?


https://en.wikipedia.org/wiki/Helical_antenna

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Old October 11th 17, 04:07 PM posted to sci.electronics.repair
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Default car antenna with serpent

On Wednesday, October 11, 2017 at 2:46:30 AM UTC-5, Andy Burns wrote:
micky wrote:

The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?


https://en.wikipedia.org/wiki/Helical_antenna


Actually, I don't believe that is the purpose. I think I've read that on automotive antennas, the winding is simply a means to reduce wind induced oscillation and noise.

Terry
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Old October 11th 17, 04:30 PM posted to sci.electronics.repair
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Default car antenna with serpent

wrote:

I think I've read that on automotive antennas, the winding is simply
a means to reduce wind induced oscillation and noise.


Ah Scruton Strakes, interesting if that's the reason ...

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Old October 11th 17, 05:35 PM posted to sci.electronics.repair
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Default car antenna with serpent

In sci.electronics.repair, on Wed, 11 Oct 2017 08:07:50 -0700 (PDT),
wrote:

On Wednesday, October 11, 2017 at 2:46:30 AM UTC-5, Andy Burns wrote:
micky wrote:

The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?


https://en.wikipedia.org/wiki/Helical_antenna


Actually, I don't believe that is the purpose. I think I've read that on automotive antennas, the winding is simply a means to reduce wind induced oscillation and noise.

Terry


Well, either one is a good reason and I'm glad to hear that there is a
reason.

It's triply important to me to reduce wind noise becausethe car is a
convertible, and I'd hear any noise it made, but I should mention that
this is my 8th convertible over 50 years and all the other ones had
standard antennas, usually in the front** but sometimes in the rear, and
I never heard any noise from them. I used to drive on the highway at
75 or even 80, but noise was the reason I dropped my max to 65. Noise
seemed to increase sharply over 65mph. So I do notice this, but it
wasn't noise from the antenna. It was wind in general, and it applied/s
whether the top was up or down. (although later cars have had a top
liner, and maybe they would be tolerable above 65mph.) The previous
car, also a Solara, a 2000, had a standard electrically retractable
antenna, also in the right rear fender, and no noise that I've noticed.

So maybe Toyota says it will be more quiet but it's just a gimmick. If
so, that would just be my second choice, "to impress people".

I still have the previous car until I get the new one repaired if
necessary and inspected, so if I can, I will take out both the old and
new ones and go 80 for a while and see if I can hear a difference. The
old one needs a lot of work but it's still as quiet as it ever was, as
the new one is.

**One or more GM cars didn't have the round antenna that deliquents used
to break off. It's cross-section was shaped like a football. At the
very least, it prevented the antenna's use for zip guns. Another was
just a wire, not telescoping, not retracting. No one ever broke my
antenna however, and the fad seems to have gone away. The custom of
slashing tops and tires of cars whose owner one doesn't know and even
when not trying to steal eanything seems to have also disappeared.


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Old October 11th 17, 06:33 PM posted to sci.electronics.repair
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Default car antenna with serpent

On 10/11/2017 02:38 AM, micky wrote:
The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?


You can use Ls and Cs to make "loaded" vertical antennas, i.e. ones that
are resonant but much shorter than 1/4 wavelength, but in those the L
goes on the bottom and the C on the top. Putting extra L on top doesn't
make immediate sense electrically, so I expect it's for acoustics or
pedestrian protection or something less obvious like that.


http://www.arrl.org/files/file/Histo...Sevick_opt.pdf

Cheers

Phil Hobbs
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Old October 11th 17, 08:41 PM posted to sci.electronics.repair
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Default car antenna with serpent

In article ,
micky wrote:

Actually, I don't believe that is the purpose. I think I've read that on automotive antennas, the winding is simply a means to

reduce wind induced oscillation and noise.

Terry


Well, either one is a good reason and I'm glad to hear that there is a
reason.

It's triply important to me to reduce wind noise becausethe car is a
convertible, and I'd hear any noise it made, but I should mention that
this is my 8th convertible over 50 years and all the other ones had
standard antennas, usually in the front** but sometimes in the rear, and
I never heard any noise from them.


My fuzzy recollection is there's a bit of a tradeoff.

Without the helical spoiler, the antenna tends to generate a fairly
uniform "wake vortex" - an alternating flow of air behind the antenna,
which switches directions repeatedly. It'll tend to be "in sync" from
the top of the antenna to the bottom. If the frequency at which the
vortex is alternating happens to match the resonant frequency of the
antenna, the antenna can vibrate - a bit like a reed in an oboe. So,
at certain speeds, the antenna can buzz or hum.

The spoiler breaks up the airflow, making it more turbulent... and due
to the helical winding it makes the turbulence different at each point
up the antenna. As a result, you can get more "broadband" wind noise,
overall, but the turbulence won't excite a physical resonance in the
antenna anywhere near as well as a "regular" vortex would, and so the
antenna doesn't sound off at specific driving speeds.

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Old October 12th 17, 09:07 PM posted to sci.electronics.repair
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Default car antenna with serpent

micky wrote:
In sci.electronics.repair, on Wed, 11 Oct 2017 08:07:50 -0700 (PDT),
wrote:
On Wednesday, October 11, 2017 at 2:46:30 AM UTC-5, Andy Burns wrote:
micky wrote:

The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?

https://en.wikipedia.org/wiki/Helical_antenna


Actually, I don't believe that is the purpose. I think I've read that on automotive antennas, the winding is simply a means to reduce wind induced oscillation and noise.

Terry


Well, either one is a good reason and I'm glad to hear that there is
a reason.

It's triply important to me to reduce wind noise becausethe car is a
convertible, and I'd hear any noise it made, but I should mention
that this is my 8th convertible over 50 years and all the other ones had
standard antennas, usually in the front** but sometimes in the rear,
and I never heard any noise from them. I used to drive on the highway at
75 or even 80, but noise was the reason I dropped my max to 65. Noise
seemed to increase sharply over 65mph. So I do notice this, but it
wasn't noise from the antenna. It was wind in general, and it applied/s
whether the top was up or down. (although later cars have had a top
liner, and maybe they would be tolerable above 65mph.) The previous
car, also a Solara, a 2000, had a standard electrically retractable
antenna, also in the right rear fender, and no noise that I've noticed.

So maybe Toyota says it will be more quiet but it's just a gimmick. If
so, that would just be my second choice, "to impress people".

I still have the previous car until I get the new one repaired if

necessary
and inspected, so if I can, I will take out both the old and

new
ones and go 80 for a while and see if I can hear a difference. The
old one needs a lot of work but it's still as quiet as it ever was, as
the new one is.

**One or more GM cars didn't have the round antenna that deliquents used
to break off. It's cross-section was shaped like a football. At the
very least, it prevented the antenna's use for zip guns. Another was
just a wire, not telescoping, not retracting. No one ever broke my
antenna however, and the fad seems to have gone away. The custom of
slashing tops and tires of cars whose owner one doesn't know and even
when not trying to steal eanything seems to have also disappeared.


Today, those youngsters seem to have given-up on keying cars and graffiti and even being outdoors at all any more. Who knows? I guess that drugs and being in front of computer screens have finally become THAT absolutely addictive.
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Old October 13th 17, 02:39 AM posted to sci.electronics.repair
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Posts: 6,963
Default car antenna with serpent

In sci.electronics.repair, on Thu, 12 Oct 2017 13:07:28 -0700 (PDT),
wrote:

micky wrote:
In sci.electronics.repair, on Wed, 11 Oct 2017 08:07:50 -0700 (PDT),
wrote:
On Wednesday, October 11, 2017 at 2:46:30 AM UTC-5, Andy Burns wrote:
micky wrote:

The antenna that came on my 2005 Toyota is about 16" long and the top
ten inches have a wire coiled around in it, like the snake on a
caduceus. Does this wire do anything or is it just to impress people?

https://en.wikipedia.org/wiki/Helical_antenna

Actually, I don't believe that is the purpose. I think I've read that on automotive antennas, the winding is simply a means to reduce wind induced oscillation and noise.

Terry


Well, either one is a good reason and I'm glad to hear that there is
a reason.

It's triply important to me to reduce wind noise becausethe car is a
convertible, and I'd hear any noise it made, but I should mention
that this is my 8th convertible over 50 years and all the other ones had
standard antennas, usually in the front** but sometimes in the rear,
and I never heard any noise from them. I used to drive on the highway at
75 or even 80, but noise was the reason I dropped my max to 65. Noise
seemed to increase sharply over 65mph. So I do notice this, but it
wasn't noise from the antenna. It was wind in general, and it applied/s
whether the top was up or down. (although later cars have had a top
liner, and maybe they would be tolerable above 65mph.) The previous
car, also a Solara, a 2000, had a standard electrically retractable
antenna, also in the right rear fender, and no noise that I've noticed.

So maybe Toyota says it will be more quiet but it's just a gimmick. If
so, that would just be my second choice, "to impress people".

I still have the previous car until I get the new one repaired if

necessary
and inspected, so if I can, I will take out both the old and

new
ones and go 80 for a while and see if I can hear a difference. The
old one needs a lot of work but it's still as quiet as it ever was, as
the new one is.

**One or more GM cars didn't have the round antenna that deliquents used
to break off. It's cross-section was shaped like a football. At the
very least, it prevented the antenna's use for zip guns. Another was
just a wire, not telescoping, not retracting. No one ever broke my
antenna however, and the fad seems to have gone away. The custom of
slashing tops and tires of cars whose owner one doesn't know and even
when not trying to steal eanything seems to have also disappeared.


Today, those youngsters seem to have given-up on keying cars and graffiti and even being outdoors at all any more. Who knows? I guess that drugs and being in front of computer screens have finally become THAT absolutely addictive.


That must be it. At least some good has come from it.



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