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).

The noise in this MP3 clip maybe is tolerable for short-term
listening, or if there is nothing better receivable.

The recording was made Jan 10, 2009 at about 12:30 pm CST.

http://www.datafilehost.com/download-18b37f18.html

RF

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/...ct-a-tenna.htm

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

On Jan 20, 11:29*am, JIMMIE wrote:


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

I wouldn't say that. Most all the auto AM radios I've had were
quite good. Always plenty of sensitivity as long as the antenna
was functioning correctly.
The current car I'm driving "Corolla" uses a small helically wound
antenna, which is at the rear of the roof. It's pretty short overall,
and I still have plenty of sensitivity. The daytime is the best time
to check that, and I've never had any trouble receiving out of
town stations. And if I tune to an open frequency, I hear background
atmospheric noise, so any increase in sensitivity is pretty much
useless. I've had older Delco radios in cars and the AM was
excellent on those.
If the OP can hear background noise when tuned to an empty
frequency, and not have it sound "dead", adding more pre-amp
is unlikely to help.
I think the main culprit in this case is propagation, and the
pattern of the array, and unfortunately, I think he's basically
out of luck. Normally you would probably be able to hear the
ground wave out to at least 200-300 miles in the daytime,
but that assumes a fairly stout signal. If the pattern is away
from that direction, even the ground wave possibilities start
to look kind of bleak.
If an auto AM radio does not have enough sensitivity, it usually
means there is something wrong with it, or the antenna.
Most as they come from the factory have more than enough.

wrote:
On Jan 20, 11:29 am, JIMMIE wrote:


The current car I'm driving "Corolla" uses a small helically wound
antenna, which is at the rear of the roof. It's pretty short overall,
and I still have plenty of sensitivity.

Newer cars have active antennas.

Dave wrote:
wrote:
On Jan 20, 11:29 am, JIMMIE wrote:


The current car I'm driving "Corolla" uses a small helically wound
antenna, which is at the rear of the roof. It's pretty short overall,
and I still have plenty of sensitivity.

Newer cars have active antennas.

The helical on some antennas is for wind noise.

On Jan 20, 8:30*pm, Dave wrote:
wrote:
On Jan 20, 11:29 am, JIMMIE wrote:

The current car I'm driving "Corolla" uses a small helically wound
antenna, which is at the rear of the roof. It's pretty short overall,
and I still have plenty of sensitivity.

Newer cars have active antennas.

I don't think mine is, but I'm not sure. It's basically the
same setup as any other antenna, just the whip is
shorter, and helically wound, I suppose for tuning purposes.
I guess it's about 15 or so inches long. I'd have to measure
it. Of course, it also functions for FM too.