AM radio

smegnl · Jun 8, 2010

socalcomet said: ↑

I was thinking of getting one of the "Secret Audio" systems and keep my original AM radio. Anybody here put one in their car?

http://cgi.ebay.com/ebaymotors/ws/e...5fffec761&rvr_id=&ua=WXI8&itemid=400079109643
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No but I looked at their site long ago for in dash vintage am/fm. here . Seems they have them for Comets but not for Mavericks

CaptainComet · Jun 9, 2010

AM (amplitude modulation) has a constant frequency and the sound is carried by carving out the top and bottom of the freq (as shown in the second part of the attached pic.) This is a very simple way of carrying sound, and was originally designed so some phones could carry their sounds further. There are two problems with this. 1) noise will also carve out hills and valleys, distorting the signal. 2) AM actually travels in two paths. One called the ground wave which follows the curve of the earth. The second is called a Sky wave witch bounces off the ionosphere and earth like a rubber ball. As stated, this is why you can hear AM better at night, MORE bounce. AM stations used to be required to reduce power at night to reduce bounce, but I do not know if that is still true.

FM (frequency modulation) keeps the carrier signal at a constant height (as shown in the last part of the attached pic). The sound is carried by squeezing the freq like an accordian. The advantage is that interference and noise cant do this and are ignored. FM only has one travel path, basically line of site. Thats why FM antennas are up high on towers and mountains, to cover more homes. FM signals do not curve to the earth like AM. The do not bounce off the ionosphere but penetrate and keep going into space.

I may not know the difference between a tie rod and a ball joint, but radio modulation, I got this b*&^%
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Mr. Jacobs ... is that you?

(Mr.J. would have been the teacher who covered this topic with me the first time ... 30+ years ago ... )

Nice explanation ... it also explains why you have a fascination with the AM radio.

Craig Selvey · Jun 9, 2010

smegnl said: ↑

Ham radio license? I have always wanted to get mine. Now that they have dropped Morse code, I just might. But ONE expensive hobby at a time man.
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mojo said: ↑

FCC broadcast license is different from ham license. Broadcast license gives you commericial operating privileges. Ham radio is non-commericial /public service/ hobby operating priveleges.
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Mojo got it.

coutangman · Jun 9, 2010

socalcomet said: ↑

I was thinking of getting one of the "Secret Audio" systems and keep my original AM radio. Anybody here put one in their car?

We put one of these systems in my son's XR7 conv back in '03. He put the receiver in the glove box and had a CD changer in the trunk. He left his original AM/FM radio in the dash and had a remote to change the channels and the CD player which he kept in the console. Worked fine for several years. When we sold the car, he took it out and sold it on Ebay. Good system.

Jim
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smegnl · Jun 10, 2010

To Much?

You know if I put this in, Id not have to fix my speedometer ....

http://www.crutchfield.com/p_020NZ409/Clarion-NZ409.html?search=car+stereo+with+gps&ssi=0

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AM radio

smegnl Roger Saffle Supporting Member

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Craig Selvey Indiana State Rep - MCCI

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smegnl Roger Saffle Supporting Member

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AM radio

smegnl Roger Saffle Supporting Member

CaptainComet Large Member

Craig Selvey Indiana State Rep - MCCI

coutangman Member

smegnl Roger Saffle Supporting Member

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