How much is AM radio used in the US these days?. Has it lost it's appeal to FM radio?, just being a poor cousin, because of static and other Electro-magnetic Interference?. Please put your 2 cents worth in-
Let's face it, these days if you're not young, you're old - Red Green
Oh ya, Awful... I mean Amplitude Modulation is still a widely used format here in So. California.
Not so much music, but many talk stations!
One certain station - with the pilot frequency of 640 kHz, will always be around (it is an alternate for some type of tracking signal, or something like that!). It is also the station heard on POTS lines when something is screwed up - like poor connections or water damage.
Read awhile back about experimental Digital AM stuff, which would give similar results found on VHF FM broadcasts.
The typical VHF FM channel is 200 kHz wide, and normally includes Stereophonic info (also Quad!). The HF AM channel is 10 kHz wide, so to get something nice for music inside this envelope, it would need to be compressed someway. Also sending Digital Packets would reduce the Atmospheric noise that gets included when the audio info gets extracted from the carrier, and sent to the power amp. (the crackles that are heard).
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!
AM was still going strong in rural Nebraska when I left there in '96. A lot of talk/news stations, parts of the public radio network with some quite interesting shows from time to time.
There were also plenty of oldies and country AM stations when I was in the South a couple of years before. (Completely unjust in my view that so many stations playing decent music go on AM while the FM band is full of the "Top 40" trash!)
Trumpy, ThinkGood mentioned KYW in Philadelphia. Just in case you're not aware of this, in general U.S. stations have W callsigns east of the Mississippi River and K callsigns west of it. There are exceptions though, such as the old-time KDKA.
Another AM broadcast difference is that in the Americas stations are on a 10kHz channel spacing, whereas elsewhere in the world we are on 9kHz (e.g. 1152, 1161, 1170 etc.)
Scott, In the U.K. AM broadcasts have always been constrained to a 4.5kHz audio bandwidth by the 9kHz channel spacing, but I seem to recall reading a few years ago that the FCC authorized some U.S. AM stations to broadcast a wider bandwidth signal, presumably only where it was deemed that the wider sidebands would not interfere with adjacent channels.
It struck me as rather odd at the time, as it would be of no benefit unless AM receivers were also designed for the wider bandwidth, in which case they'd be wide open to adjacent channel interference when tuned to weaker "normal" stations.
I have a feeling that the piece I read was in error, but can you confirm this?
[This message has been edited by pauluk (edited 01-31-2003).]