Hi all,

I've looked on the web, but with very little success. I have never
posted to this group before, so I apologize if my question is lame.

I listen to the Bay Area's KGO 810 MHz a lot. Their transmitter is
located in South San Fran Bay near the Dumbarton Bridge, and outpus 50
kW (that's what they say anyway). I am guessing, it's directed mostly
at the Pacific coast line. 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). By the time I reach Auburn
it's essentially inaudible. Much better signal at night (~again, by
ear, S/N improves by ~2). At night, I can sort of pick up words in
truckee.

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? I do not care if the antenna is
huge/geeky_looking, my car is being driven into the ground anyway. I
would be happy to make this a DIY project - to save on $ and learn
about radio. What kind of specs should I look for? I.e. I don't want
to go on the web and blindly buy an antenna advertised to "boost" your
AM radio reception - I would want some numbers.

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.

wrote:
Hi all,

I've looked on the web, but with very little success. I have never
posted to this group before, so I apologize if my question is lame.

I listen to the Bay Area's KGO 810 MHz a lot. Their transmitter is
located in South San Fran Bay near the Dumbarton Bridge, and outpus 50
kW (that's what they say anyway). I am guessing, it's directed mostly
at the Pacific coast line. 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). By the time I reach Auburn
it's essentially inaudible. Much better signal at night (~again, by
ear, S/N improves by ~2). At night, I can sort of pick up words in
truckee.

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? I do not care if the antenna is
huge/geeky_looking, my car is being driven into the ground anyway. I
would be happy to make this a DIY project - to save on $ and learn
about radio. What kind of specs should I look for? I.e. I don't want
to go on the web and blindly buy an antenna advertised to "boost" your
AM radio reception - I would want some numbers.

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.

If you have mobile Internet try this:-

http://wareseeker.com/Windows-Widget...1.2.zip/313700

HTH

Clive

If you have mobile Internet try this:-

http://wareseeker.com/Windows-Widget...player-1.2.zip...

HTH

Clive

That's a good one. I am often in places with no cell reception. I
originally discovered KGO when I lived in La Honda, CA - it was the
only radio station I could easily pick up. No cell reception and no FM
there.

wrote in message
...
Hi all,

I've looked on the web, but with very little success. I have never
posted to this group before, so I apologize if my question is lame.

I listen to the Bay Area's KGO 810 MHz a lot. Their transmitter is
located in South San Fran Bay near the Dumbarton Bridge, and outpus 50
kW (that's what they say anyway). I am guessing, it's directed mostly
at the Pacific coast line. 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). By the time I reach Auburn
it's essentially inaudible. Much better signal at night (~again, by
ear, S/N improves by ~2). At night, I can sort of pick up words in
truckee.

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? I do not care if the antenna is
huge/geeky_looking, my car is being driven into the ground anyway. I
would be happy to make this a DIY project - to save on $ and learn
about radio. What kind of specs should I look for? I.e. I don't want
to go on the web and blindly buy an antenna advertised to "boost" your
AM radio reception - I would want some numbers.

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.


Presumably you mean 810 kHz. What is the source of the noise? Noise
generated in the receiver is usually insignificant in the medium-wave band.
If the cause is other transmissions on the same and nearby frequencies you
may not gain much by changing the antenna, but a receiver with better
channel (IF) filtering may help if there is any contribution from adjacent
channels. If the noise is coming from your car (does it improve when you
park in a rural area) then you may need to improve the RF suppression of its
circuitry (e.g. ignition if it's a petrol engined car).

I expect you can work out what tests would be needed to locate the principal
sources of the noise.

Chris

Presumably you mean 810 kHz. *What is the source of the noise? Noise
generated in the receiver is usually insignificant in the medium-wave band.
If the cause is other transmissions on the same and nearby frequencies you
may not gain much by changing the antenna, but a receiver with better
channel (IF) filtering may help if there is any contribution from adjacent
channels. *If the noise is coming from your car (does it improve when you
park in a rural area) then you may need to improve the RF suppression of its
circuitry (e.g. ignition if it's a petrol engined car).

I expect you can work out what tests would be needed to locate the principal
sources of the noise.

Chris

Yes, KHz, sorry.

The noise goes up several fold when I pass underneath bridges/pass big
trucks, etc. Does this suggest that the noise is from other
frequencies?

wrote:

Yes, KHz, sorry.

The noise goes up several fold when I pass underneath bridges/pass big
trucks, etc. Does this suggest that the noise is from other
frequencies?

No. It means that the noise is coming from outside your car. Your
antenna and radio can't tell the difference between this noise and the
desired signal, so improving your antenna or increasing your receiver's
sensitivity will simply increase the signal and noise in the same
proportion. And because it's not coming from your own car, there's no
way for you to reduce the noise. In other words, there's really nothing
you can do to improve the S/N ratio in the presence of that noise.

Roy Lewallen, W7EL

On Jan 19, 3:38*pm, Roy Lewallen wrote:
wrote:

Yes, KHz, sorry.

The noise goes up several fold when I pass underneath bridges/pass big
trucks, etc. Does this suggest that the noise is from other
frequencies?

No. It means that the noise is coming from outside your car. Your
antenna and radio can't tell the difference between this noise and the
desired signal, so improving your antenna or increasing your receiver's
sensitivity will simply increase the signal and noise in the same
proportion. And because it's not coming from your own car, there's no
way for you to reduce the noise. In other words, there's really nothing
you can do to improve the S/N ratio in the presence of that noise.

Roy Lewallen, W7EL

increase the signal and noise in the same proportion.
Is there anyway to "filter" the 810 frequency somehow?

wrote in message
...
On Jan 19, 3:38 pm, Roy Lewallen wrote:
wrote:

Yes, KHz, sorry.

The noise goes up several fold when I pass underneath bridges/pass big
trucks, etc. Does this suggest that the noise is from other
frequencies?

No. It means that the noise is coming from outside your car. Your
antenna and radio can't tell the difference between this noise and the
desired signal, so improving your antenna or increasing your receiver's
sensitivity will simply increase the signal and noise in the same
proportion. And because it's not coming from your own car, there's no
way for you to reduce the noise. In other words, there's really nothing
you can do to improve the S/N ratio in the presence of that noise.

Roy Lewallen, W7EL

increase the signal and noise in the same proportion.
Is there anyway to "filter" the 810 frequency somehow?

Hi

Are you certain that the noise increases? I suspect the "signal"
decreases. It is entirely possible that the antenna on your vehicle is
inadequate.
Car antennas are *not* simple. They do appear simple. They often appear
to be a whip mounted above the fender. The way that fender whip is
connected to the receiver is critical.

Depending what type vehicle you have, the increase of sensitivity to 810
KHz could be to mount a stub atop the fender and connecting it to the
receiver with a Low Capacity coax line. In addition, the receiver can be
tuned at the place where the antenna connects to the first amplifer to
maximize sensitivity to 810 KHz.

Many new cars include an amplifier at the base of the antenna to increase
sensitivity.

Are you open to taking your car to a specialist to let them try to tune
your "antenna" to your receiver?

Jerry KD6JDJ

wrote:
Presumably you mean 810 kHz. What is the source of the noise? Noise
generated in the receiver is usually insignificant in the medium-wave band.
If the cause is other transmissions on the same and nearby frequencies you
may not gain much by changing the antenna, but a receiver with better
channel (IF) filtering may help if there is any contribution from adjacent
channels. If the noise is coming from your car (does it improve when you
park in a rural area) then you may need to improve the RF suppression of its
circuitry (e.g. ignition if it's a petrol engined car).

I expect you can work out what tests would be needed to locate the principal
sources of the noise.

Chris

Yes, KHz, sorry.

The noise goes up several fold when I pass underneath bridges/pass big
trucks, etc. Does this suggest that the noise is from other
frequencies?

Does it do this for KKOH as well? Try 780 and see if it exhibits
similar behavior. If not, it's the KGO signal. They are pretty anemic
to the East North East.

http://www.fccinfo.com/CMDProEngine....49372&sHours=U

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