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Discussion Starter · #1 ·
My radio has really bad reception, but my mechanic can't find where the Antenna is to make sure its not grounded or disconnected

Where is it?

Thanx
Doug
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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Are you still using the factory radio? There is a diversity antenna that is printed onto the rear window as part of the rear defogger grid.
Patent US6239758 - Vehicle window antenna system
There is also an antenna amplifier module. Check for 12 volts and ground.
DCP_0946-vi.jpg
AM needs more of an antenna than FM, so you may have little or no AM reception if there is an antenna problem.
First make sure that everything is plugged in and there are no pinched wires. A 3' long piece of wire can be used as a substitute or test antenna in the back of the radio to make sure that it is an antenna problem and not a radio problem.
 

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KOG
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You'll get better reception if you add a real antenna.
 

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Discussion Starter · #4 ·
ImperialCrown
Thanx, I assumed it was in either the front or rear window.

Knowing about the Amplifier is helpful to.
The photo you provided looks like its in the trunk, maybe under the rear window tray or on the trunk side of the back seat.

The Radio Station I get poor reception on sometimes is a 50K Watt AM local station right here in Albuquerque, so if I get poor reception, I'm betting its in the electronics.

Thanx again
Doug

Are you still using the factory radio? There is a diversity antenna that is printed onto the rear window as part of the rear defogger grid.
Patent US6239758 - Vehicle window antenna system
There is also an antenna amplifier module. Check for 12 volts and ground.
DCP_0946-vi.jpg
AM needs more of an antenna than FM, so you may have little or no AM reception if there is an antenna problem.
First make sure that everything is plugged in and there are no pinched wires. A 3' long piece of wire can be used as a substitute or test antenna in the back of the radio to make sure that it is an antenna problem and not a radio problem.
 

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KOG
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Very much so. I did radio/microwave in the Army and have some antenna knowledge. Was working for the local Cadillac/Olds/Nissan dealer in 1970 when GM switched to windshield antennas. On of the first "assignments" I was given was to reinstall the radio in a 98 that had been on the lot unsaleable for 3 months because the radio wouldn't work. They had sent the radio out for repair three times and each time when it came back it wouldn't work, so they sent it back. Problem, of course, was the antenna. The lead was pulled loose at the base of the windshield under the dash where it wasn't visible. None of the mechanics in the place had any clue about radio and didn't know to stick a test lead into the antenna socket on the radio to see if it would then work. So it went to the body shop for a new windshield.
 

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Discussion Starter · #7 ·
I dig out my Haynes manual for the LH Cars and it showed the Antenna Integrated into the rear window and the booster

Drove it a lot yesterday for the first time in months, after my mechanic did some work under the dash and it seemed much better

Thanx
Doug

Very much so. I did radio/microwave in the Army and have some antenna knowledge. Was working for the local Cadillac/Olds/Nissan dealer in 1970 when GM switched to windshield antennas. On of the first "assignments" I was given was to reinstall the radio in a 98 that had been on the lot unsaleable for 3 months because the radio wouldn't work. They had sent the radio out for repair three times and each time when it came back it wouldn't work, so they sent it back. Problem, of course, was the antenna. The lead was pulled loose at the base of the windshield under the dash where it wasn't visible. None of the mechanics in the place had any clue about radio and didn't know to stick a test lead into the antenna socket on the radio to see if it would then work. So it went to the body shop for a new windshield.
 

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Early (1970s-80s) GM had horrible problems with the embedded windshield antennas. They were directional, they were affected by wiper operation and as noted, if the connector wires broke at the base of the windshield, they were awful to repair.
Nowadays, these printed (not embedded in the glass) are much better and many automakers are using them.
Radio gain/noise rejection circuitry has also improved vastly since the 1970s.
 
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AM is more susceptible from interference noise from failed electronics in the vehicle. That also can be a possible cause of the sudden poor reception in AM.

Granted its an aftermarket radio in my 2010 Jeep, but my aftermarket radio also needed a 3rd party translator for the CAN Bus to retain the steering wheel controls. The 3rd party translator I selected burned out twice, each time it burned out, my AM reception went to pot, only the closest strongest stations could be tuned with a lot of background noise like they were a distant station. Each time I replaced the burned out electronic component, the AM reception returned to its original quality until it would burn out again. I thought I had an antenna problem as well, until the 2nd time the translator burned out, and reception changing immediately with the failure of the electronic device was too much of a coincidence.
 

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Early (1970s-80s) GM had horrible problems with the embedded windshield antennas. They were directional, they were affected by wiper operation and as noted, if the connector wires broke at the base of the windshield, they were awful to repair.
Nowadays, these printed (not embedded in the glass) are much better and many automakers are using them.
Radio gain/noise rejection circuitry has also improved vastly since the 1970s.
I had two GM vehicles from the late 70's ('79 Monza and '79 El Camino). As I recall both had the embedded antenna's. They were okay as I never had reception problems. Both were equipped with AM radio only (ugh!). I added a FM converter to the Monza. It worked quite well for a $15 unit.

With AM I could get distant radio stations at night. Quite often I would get a signal from a radio station in Buffalo, NY (I'm 600 miles to the south). At times it would be stronger than some of the local AM stations.
 

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A friend was complaining about bad radio reception in his 79 LeBarron. We took a look at the radio and I had discovered a single strand of wire sticking out the end of the center pin on the antenna connector and it was long enough to fold back to ground out the antenna.

Typically for AM reception the longer the better for an antenna. But for FM a 1/4 wave length which is 31 inches and this is the length of the fixed mast antennas on older cars.

Yes I agree with Rick that AM is very susceptible to interference from other electrical sources. Lightening, bad insulators on a power pole, etc.... Once I had a car where I could hear the wiper motor in the AM radio.
 

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Remember,

AM frequency band is in the kHz, Thousands of Hz's.
FM frequency band is in the MHz, Millions of Hz's.
Satellite frequency band is in the GHz, Billions of Hz's.

The lower the frequency the longer the wavelength. Which changes how the antenna works as well. But longer frequencies means further range, as well, as night approaches, atmospheric effects bends and bounces the waves off different layers of the atomsphere. I've gotten powerful AM stations from several states away at night, but as I drove closer to the source, I lost the signal (because I was receiving the signal from a bounce off the troposphere, that I drove out from under it, even though I was closer to the source).

I "think" because of AM's long wavelengths they use funky antenna strategies and the receiver has to be more sensitive, that is why they are so susceptible from radio interference. I "think" with AM you need a 50' long wire as an antenna or you have to use something like a wire coil around an magnet.

Who's had the AM radio tach, you can tell the engine rpm by the background rumble in the AM radio. The ignition would cause the rumble, much more prevalent in the older cars with Distributors.

FM is better sound quality but shorter range. When someone insists FM has better range than AM, they usually mean that they have a certain level of sound quality they are willing to accept, and FM will sound better despite the distance compared to AM. But, if you're willing to put up with the noise, AM can be received much farther out.

Satellite meanwhile is line of sight, a direct line between you and the satellite, it barely bends at all.

NOT to mention AM means amplitude modulation and FM means Frequency Modulation. The way the sound is encoding into the radio waves makes a difference as well.

And finally, if you haven't had a chance to listen to "HD" radio, i.e. Digital Radio, you don't know what you're missing. I'm surprised it hasn't taken off more than it has already.
 
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FM also has trouble propagating in hilly or mountainous terrain while AM can reach farther into and between the hills as an advantage.
I had always thought that 'HD' radio stood for 'High-Definition' but it is just a trademark term for iBiquity's digital radio technology.
HD Radio - Wikipedia, the free encyclopedia
The compressing of the audio stream to save space (bandwidth) also takes away from the dynamics and fidelity of the music. Voice not so much. Some people can't hear the difference and to them, HD is fine.
Compressed audio and economical bit sampling rates take away from the way that the music was meant to sound. Some describe it as being harsh or shrill.
My ears aren't that good now, but I did play musical instruments when I was younger. Both my parents were music teachers. I do prefer analog sound reproduction any day.
 
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Perhaps they couldn't trademark "High-Definition" radio, so they used "HD" radio meaning something else, but counting on consumers to automatically associate it as "High-Definition" because of the use of HD.

Well, first the fact the sound is digital encoded into the signal makes it far more effective at filtering out the noise introduced while it travels over the air, when the receiver decodes it. So you do get a much cleaner and clearer sound, despite it being compressed.

2nd the audio compression can be deceiving, when you read how it works you can't help but conclude there must be loss in the audio quality. If you read more about it, you find the various compression schemes have been developed over years to minimize the impact on the final quality after being decompressed. The schemes are designed to find where sounds cancel each other, things outside the range of human hearing, etc. In reality for the good compression schemes, all except perhaps the most expert ears, can't tell a difference. I know I can't. I'm pretty sure, the switch to digital produces more actual bandwidth coming across, despite it being compressed, than the analogue signal, for a net gain in sound quality.

So, I think its a combination of digital getting rid of more noise, and the compression being good enough NOT to degrade the sound, and the ability to carry more data over the same signal that the end result is better quality than the analogue signal did before. The argument over compression comes down to, could they have made the sound quality even better devoting all the extra bandwidth for one channel instead of dividing it up into 3 channels on one frequency, with each of the three having a little better sound quality than the single analogue.

For those that haven't experienced HD radio, once the radio locks onto the frequency and switches over to digital, it gives you the ability to switch between three different channels on that frequency, one is the replica of the analogue you first tuned, the other two are entirely different content, often the sister station for the broadcaster.

Finally, I have read that HD-FM radio is "Compact Disc" audio quality, when the radio tunes in the analog then switches to digital you can notice the jump in sound quality and to my ears it is CD quality. You can definitely tell the sound gets clearer with no noise and clearer, but there is also a richer sound like it has broader bandwidth (and I do think it does).
 
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