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Old January 20th 09, 05:29 PM posted to rec.radio.amateur.antenna
JIMMIE JIMMIE is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 625
Default improve S/N for AM car radio by a factor of 2...5...10?

On Jan 20, 7:58*am, Dave wrote:
Richard Fry wrote:
On Jan 19, 7:14 pm, Jeff Liebermann wrote:
Daytime coverage map:
http://www.radio-locator.com/cgi-bin/pat?call=KGO&service=AM&status=L...
2.5, 0.5 and 0.15 mV/m contours. *It still should be usable in
Sacramento. *Something is wrong.


Agree. *The link below leads to an example of the noise on a weak,
daytime AM signal received from WBBM, Chicago (50 kW non-D on 780 kHz)
on a Sony ICF-2002 with its internal antenna, indoors in an urban
location. *The groundwave path from WBBM to the receiver is about 225
miles in length. *According to the FCC propagation curves, WBBM has a
daytime groundwave field intensity of about 0.14 mV/m for this path
(probably less in an urban area).


In this situation a Select-A-Tenna will work wonders. *No good for a car
radio, however.

http://www.old-fashioned-values.com/...enna_improve-a...


On a lot of AM auto radios the SN ratio really stinks and an external
preamp especially one with some preselection can really help. As
previously stated on radios with adequate sigal to noise ratio adding
a preamp just makes things worse.


Jimmie