Yes, 0.3 µV is a rather decent sensitivity for an AM tuner in a car stereo, but what Signal-to-Noise ratio does the radio produce with a 0.3 µV signal present at the frequency you're tuned to? Also important is the selectivity. If the tuner is poor at separating channels then high sensitivity may be a disadvantage, because stronger stations will tend to bleed over onto an adjacent channel(s).
Many of the car stereo manufacturers are more likely to give more detail for their FM tuner specifications than for their AM tuner. Perhaps an automotive electronics website/magazine or even Consumer Reports may have tested car stereos. If there is a decent car stereo store (independent, not a big-box store like Best Buy if you can avoid stores like that) in your area, it would be best to try the radios out for yourself in the store (assuming the store has made the effort to ensure decent FM
and AM reception) to see how they perform. Then, write down the model number(s) of the radio(s) you're interested in, say thanks and find a better price online than at the store. Crutchfield.com might have some specs to compare side-by-side.
I have an Alpine in one of my vehicles (Honda) and the other is a factory radio (with R
BDS) in my Ford. I have decent reception on both, so no need to change the radio on either, I'm satisfied with their reception. Some remarks from the blog from which the comment below was made said, 'make sure your antenna is functioning at its best efficiency'. Sometimes reception has gradually deteriorated over time because an antenna has become weathered, or the connections have possibly weakened. Of course, many of today's vehicles have in-glass antennas so that may not be an issue. Many of today's vehicles also have a densely packed dashboard, so if you're thinking of attempting to replace the radio yourself, read up on what's involved in installing a car stereo first. You may find it worthwhile (and a lot less frustrating) to have the new radio installed professionally.
"A few years ago when I worked in the Car Audio industry, we did some radio reception comparisons among manufacturers. The clear winner in this field was Alpine clos
ely followed by Pioneer. Of course there were some variance in models (you get what you pay for at the end of the day) but in comparable models and price points Alpine was the model to go for Radio reception, they also had one of the better CD mech
anisms as well."
http://www.geekzone.co.nz/forums.asp?forumid=48&topicid=18572
shepaug said:
What exactly does that mean ? A 1kw signal you can hear for 10 kilometers or ?
Well, it could be only 6 miles or so if the station is at the high end of the AM band, highly directional, and most of the signal is "screened" or aimed away from your listening location. A 1kW omnidirectional AM station should be audible from over 200 miles on the low end (like 550kHz) on the AM band, dropping to just over 100 miles (near 1000 kHz), but only about 50-75 miles on the high end of the band (1600 kHz). This is for groundwave, daytime.
I think what you may be trying to say is
how is the sensitivity of a radio related to a radio station's signal contour? Well, they're somewhat related. The signal contours are the expected reach of the station's signal out to varying distances, depending on station power, frequency, efficiency of the transmitting tower/s, whether it's omnidirectional or directional, ground conductivity, and several other factors. There comes a point where the signal is gone, and no tuner, no matter how sensitive, will "hear" that signal. But, it's always a good idea to have the most sensitive tuner than you can get (with reason of cost and practicality) That way, you can hear more stations, further away from their transmitters. More sensitive tuners will certainly make up for weaker stations...up to a point.
Though I might not trust radio-locator.com 100% of the time on their signal contour maps, these maps may give one a fair idea of what to expect on signal range from a given station. A decent AM tuner in a car stereo ought to be able to hear out to the purple, or "distant" contour in the daytime. At night, depending on the frequency, and how many stations might occupy that frequency at night, the results may differ considerably from the nighttime contour map for each station. On the higher end of the AM band, and depending on the ground conductivity, the contour maps for daytime reception may be a bit generous IMHO as to how far the distant signal contour goes out. Like the disclaimer says: "your results may vary".
Even some locals range from nearly unreadable to quite noisy under the extreme (indicating 50/00 from somewhere in the 1100s to 1500s, and 49/00 from somewhere in the 900s to the top of the band on the Tecsun PL-380 and Grundig G8 (I haven't taken the PL-606 there yet), including 1230 KYPA, 1260 KGIL, 1280 KFRN, 1330 KWKW, 1390 KLTX, 1460 KTYM, 1480 KVNR, 1580 KBLA and 1650 KFOX.