Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: AM Radio Noise  (Read 471 times)
VE7HHO
Member

Posts: 11




Ignore
« on: January 03, 2005, 03:43:03 PM »

I just installed a new car radio deck in my car.  There is noise in the AM channels especially a certain station.  (The engine is not running.)  But when I connect a small pocket radio (Aiwa) to the auxillary input of the deck and listen to the AM stations, there is no noise.  I have tried to ground the chasis of the deck and the noise is still there.  Could someone please give me some advice on how to eliminate that noise?
Logged
WB2WIK
Member

Posts: 20595




Ignore
« Reply #1 on: January 03, 2005, 03:51:05 PM »

You didn't describe the noise in much detail, but if it's "hiss" from being a weak signal, I'd guess the antenna isn't connected to the radio -- or at least not functioning as an "AM" antenna (while it might work fine for "FM").

The little Aiwa, being a complete receiver and probably having its own built-in antenna, might simply be receiving a stronger signal, hence the lack of "hiss."

Could that be it?
Logged
VE7HHO
Member

Posts: 11




Ignore
« Reply #2 on: January 03, 2005, 05:39:20 PM »

Hi WB2WIK,
Thank you for your reply.  
The noise is "hiss" at the background.  I did attach the car antenna.  When the car antenna is unplugged, nothing can be heard.  I think the little Aiwa should not be better than a radio deck.
Logged
WB2WIK
Member

Posts: 20595




Ignore
« Reply #3 on: January 04, 2005, 08:15:12 AM »

The little Aiwa might very well be better than the radio deck, if the antenna on the radio deck doesn't work well or is somehow broken.  That is a VERY common problem on motor vehicles: The coax and connector used for the radio antenna are very fragile and easily broken by handling or plugging/unplugging.  I've broken several myself, over the years, just installing new equipment in my own cars.

So, you might start there, by inspection and test of the antenna and its cable/connector.

If that all appears well, it is possible the radio deck has a defective AM section.  A lot of people never use the AM section of their car radios (I know I never do), so as long as the FM stereo part works, they're happy and don't even know the AM section is defective.  

Also, there is often (usually) an antenna trimmer adjustment for the AM radio.  It does not affect the FM radio at all, only AM, and is there to tune the AM receiver's front end to match the car antenna.  If it's factory adjusted and has not been re-adjusted to match your antenna, that can make a big difference.  You might refer to the installation manual for the deck to see if they discuss this.

WB2WIK/6
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!