RadioBanter - View Single Post - improve S/N for AM car radio by a factor of 2...5...10?

Jeff Liebermann[_2_] · January 20th 09, 01:14 AM posted to rec.radio.amateur.antenna

On Mon, 19 Jan 2009 13:15:11 -0800 (PST),
wrote:

I often listen while driving east on I-80
to Truckee/Tahoe for skiing and camping. Usually the signal fades
substantially by the time I reach Sacramento - but it's still
tolerable listening (by ear, S/N of ~3).

Daytime coverage map:
http://www.radio-locator.com/cgi-bin/pat?call=KGO&service=AM&status=L&hours=D
2.5, 0.5 and 0.15 mV/m contours. It still should be usable in
Sacramento. Something is wrong.

When you're in Sacramento, have some other driver try their vehicles
AM radio on KGO and see if it's the same. If it's better, it's time
to go shopping for a new radio or a new antenna system on your
vehicle. In particular, try to find a real short wave radio with an
ignition noise blanker, to use for the comparison. Also try it with
the engine off and see if things improve. If all the other radios and
conditions sound roughly the same, give up.

Incidentally, there's usually an adjustable trimmer capacitor to tune
the car antenna somewhere on the radio. It's usually hidden behind
the volume or tuning dial (on older radios with dials) or right on the
front panel on later model radios. Find a weak station and tune for
maximum.

Question: can I *substantially* improve the S/N - say, factor of
2/5/10 by installing a better car antenna, so that, say, I could
listen in the Sierras day and night?

No. Look at the map. You're in fringe-land in the Sierras. The only
way that's going to work is if you get away from local noise sources
(i.e. engines, get a decent antenna, and if propagation is in your
favor). It's possible, but not guaranteed or reliable. Back when I
was getting started in radio, I was a SWL (short wave listener) which
included listening to distant AM broadcast stations. I could hear the
world, but only at random times, not for very long, and certainly not
with armchair listening quality.

Strangely enough, some practice listening to a noisy AM station may
actually improve the quality. I was out of radio for perhaps 15
years. When I dived back in, I couldn't understand anyone on the
radio. It took about a month of listening to "tune" my ear so that I
would mentally ignore the noise and interference. The same thing
happened when I spent 10 years driving back and forth to Smog Angeles
twice a month. I would listen to KSCO on the way. The more I
listened, the better the station sounded.

I do not care if the antenna is
huge/geeky_looking, my car is being driven into the ground anyway.

A big antenna may not help much. It will pickup more signal, but also
more noise. The ratio of the signal to the noise will remain roughly
constant, resulting in no net improvement.

I have limited knowledge in electronics, my background mostly is in
biophysics and biochemistry. So if you steer me into the right
direction I think I should be able figure it out.

You might look into satellite radio (XM/Sirius). They don't have KGO
but might have equally useful or interesting programming. The nice
part is that it works anywhere.

On the other hand, if you don't need current listening, just have
someone record a days worth of KGO in MP3 format, and play it on a
cheap MP3 player. It may be a day late, but unless you're into the
news, weather, traffic, or sports, it probably doesn't matter being a
day late.

Google Maps
http://maps.google.com/maps?f=q&hl=en&q=37.52639,+-122.10056+(KGO-AM)&om=1

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS