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Radio Reception

N

nykbob

GUEST
Has anyone noticed their FM radio reception is less that you would expect? All my other vehicles have gotten good FM reception in my area. Now my AV seems to loose stations as I drive. Am I having a specific problem, or is this an AV or antenna problem?
 
Don't want to get off topic, but....

I don't listen to FM; only XM. Everyone on this site that has had it installed thinks it's great. At least from the posts that I have read.

The only thing I listen to is XM and mp3's.

Just my .02

--chazj
 
I have the '03 Bose 6 Disc Chgr, and actually was impressed by the reception I had over the Kenwood in my prev vehicle. I'd have it checked.
 
Welcome to the club


As irontrain said I had weak reception until I installed the steering wheel radio controls....at that time
i had to remove radio and unplug antenna wire which was tight...but after reinstalling everything the reception improved greatly..

 
nykbob-- I too have noticed poor FM reception on my AV.
The dealers answer is "we'll take it out and send it for service". So while it's out for service I drive around w/out a radio? I don't think so!!!!! Ummm... it's a new vehicle couldn't they swap it? Or should I ask wouldn't they swap it out? Or maybe it's time to do the stereo upgrade.
 
My reception is very poor. I traded in a 2002 silverado with the same radio and This one has considerably worse reception. Lets figure out a fix.
 
Let us know when you get the reception on the '02 radio fixed. Mine is bad. This is the second radio (first one lost time....this one has also) so it must be the design.
 
I just took my AV in for a service check and had them check the radio. They said part of the problem could be because I have the video player installed. This can?t be because I was having the problem for the two weeks before they put the video player in. They did disconnect and reconnect the antenna so I?ll see if that makes a difference. If not I?ll try a few more things before I go for a different antenna. I?ll let you know. ???
 
I have noticed that the radio reception is much weaker than that of my 99 GMC Sierra. I have mentioned this to my dealer without result. This morning I was listening to a FM station which came in fairly clear. I stopped for gas and when I started up the AV, the reception was terrible. I think something is wrong with this picture. Anyone else have this problem???? ???
 
There's certainly a problem with yours. Factory units usually work really well when it comes to sensitivity, selectivity and handling overloading signals. My FM reception (actually both) was just fine until I removed the antenna. (Because I never use it anymore - XM!!)

 
The GM Delco am/fm have one of the best tuners out there.. But as said before. I too have Sirius and Xm. I haven't heard fm or am in a LONG time....
 
What do you want for a $1200.00 head unit...You can't see it in the day time and the tuner sucks. But to this day it has the best SQ for a cd head unit...Burr-Brown baby.. (y)
 
You can check the antenna connection.. Pop off the dash bezel, remove the HU screws (7MM hex head), tilt it out & back, then re-seat the antenna connector. You'll never know until you try it...

Aside from that, they'll just remove it and send it to a service/warranty station, without even checking the antenna or cable...

782084.gif


(1)   Negative Battery Cable
(2)   Coaxial Cable Conductor - Radio End
(3)   Coaxial Cable Metal Outer Shield - Radio End
(4)   Coaxial Cable Metal Outer Shield - Antenna End
(5)   Coaxial Cable Conductor - Antenna End
(6)   Antenna Base
(7)   Antenna Mast
(:cool:   Antenna Coaxial Cable
 

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Here's a document: Note that the zip process has trouble with compressing gif's, so just copy the image from my previous post and copy over the same file in the subdirectory (after it's extracted of course!) This zip HAS a subdirectory, make sure your zip extractor "knows"!

This is the same as the doc below...
 
Document ID# 766040
2004 Chevrolet Avalanche​

Radio Poor Reception

Diagnostic System Check - Entertainment System

Always perform the Radio/Audio System Diagnostic System Check before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Entertainment System

Antenna System Test

Important

Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.


1. Disconnect the negative battery cable.
2. Disconnect the antenna lead-in connector from the radio receiver.
3. Measure the resistance from the negative battery cable to the coax outer conductor connector.
4. The resistance measured should be 0.20 ohms or less.
5. Test the following when the resistance is greater than 0.20 ohms.
* Base of the antenna for a poor connection to body ground.
* The coaxial cable interconnects for a poor connection or corrosion.
* Test for an open or high resistance from the battery negative cable to the body. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
6. After finding and correcting the condition, operate the system in order to verify the repair.

Perform the Antenna Checking Procedures after confirming the integrity of the antenna ground.

Antenna Checking Procedures

Perform the following tests for the type of antenna on the vehicle.

Mast Antennas

Unplug antenna lead-in connector from radio receiver and plug a test antenna into radio. Make sure antenna base is grounded to the vehicle chassis and keep hands off the mast.

Check radio reception in an area away from electrical interferences. Tune to several weak and strong AM and FM stations. If the radio reception improved, the problem exists with the antenna and/or lead-in cable. If the reception is still poor, refer to Audio System Troubleshooting Hints

Important

Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.


782084.gif


(1) Negative Battery Cable
(2) Coaxial Cable Conductor - Radio End
(3) Coaxial Cable Metal Outer Shield - Radio End
(4) Coaxial Cable Metal Outer Shield - Antenna End
(5) Coaxial Cable Conductor - Antenna End
(6) Antenna Base
(7) Antenna Mast
(:cool: Antenna Coaxial Cable

Ohmmeter Probes At Points

Resistance Measured In Ohms

The chart woundn't position here - Look below, Sorry!
766040-Chart.gif



Refer to the table when testing the antenna and/or lead-in cable.

1. Measure the resistance from the coax center conductor to antenna mast.
2. Total resistance from end to end of center conductor:
* RG-58/RG-59 type cable -- less than 0.20 ohms
* RG-62/RG-62M type cable -- less than 3.5 ohms
3. When checking the resistance, cautiously wiggle the lead-in tip and cable. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
4. Measure the resistance from the cable center conductor to metal case.
5. Replace the antenna and/or lead-in cable when the above readings are not obtained.

Diversity Antenna System <- NOT Avalanche!

Important

This diversity antenna system is comprised of 3 glass mounted antennas, a radio antenna module, and an FM impedance matching module. The primary AM and FM antennas are an integral part of the right rear quarter glass and are connected to the radio antenna module. The secondary FM antenna is an integral part of theleft rear quarter glass and is connected to the FM impedance matching module. The radio antenna module processes the antenna reception signals and phase aligns them to create one strong signal. The FM impedance matching module boosts the secondary antenna signal and transmits it to the radio antenna module.

The following information lists the most probable cause of the concern to the least probable cause followed by the appropriate test for that condition. If the test leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. If the test leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement.
Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Perform the Antenna System Test and test the antenna coax cable prior to performing any of the following tests.

* Poor Reception on Both AM and FM Bands

The radio antenna module is not grounded properly. The module grounding screws should be clean and tight. The antenna module ground is either a chassis ground or a ground strap. Measure the resistance from the antenna module base plate to a good ground. Resistance should be 0.20 ohms or less. Find and correct the condition if the resistance is out of specification.
* The antenna enable signal is not present at the radio antenna module. This could be caused by an output failure of the radio or an open/shorted antenna enable signal circuit. In order to test the antenna enable signal circuit, the radio must be ON and tuned to the FM band. Disconnect the radio antenna module. Measure the voltage from the antenna enable signal circuit of the radio antenna module to a good ground. Voltage measured should be near 12 V. If the specified voltage is measured, test the antenna enable signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no failures were found, replace the radio. Refer to Radio Replacement for service procedure.
* The FM composite signal circuit to the radio antenna module is open or shorted to ground. Test the FM composite signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
* The feed coax at the radio antenna module has been inadvertently swapped with the FM impedance matching module crossover coax. Ensure that the feed coax, marked with a yellow band, is in the correct socket on the radio antenna.
* Improper retention of the antenna cable in the floating retainer. Poor or no connection with the radio will result when the radio is installed if the antenna cable is not properly attached in the floating retainer. Inspect the antenna cable for movement in the floating retainer. Replace the antenna cable if movement is found.
* Defective Radio Control Module. Replace Radio Control Module. Refer to Module Replacement - Radio Antenna Diversity for service procedure.

Poor Reception on AM Band Only

*Defective AM antenna.
* Defective Radio Control module. Replace Radio Control Module. Refer to Module Replacement - Radio Antenna Diversity for service procedure.

Poor Reception on FM Band Only

* Defective primary or secondary FM antenna
* Defective Radio Control Module. Replace Radio Control Module. Refer to Module Replacement - Radio Antenna Diversity for service procedure.
* Defective Radio Antenna Module. Replace Radio Antenna Module. Refer to Module Replacement - Radio Antenna Diversity for service procedure.
 

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