If you think 1,000 kW on AM is a monster, you should know there are a few stations running 2,000 kW. For instance the Hungarian station on 540 uses five 400 kW Nautel units running in parallel to achieve the two megawatt power output.
Yep..the human ear doesn't hear that much energy above 10kHz..listening to FM and AM stereo stations with same music and decent receivers, you hardly notice the difference...less bass in AM stereo, usually cuts off below 100Hz..to prevent interference with the 25Hz pilot.
But you said: "The human ear doesn't hear that much energy above 10kHz." There was never a claim of flat response.
If you look at the energy in music, it's more below 10k than above. Hence the human ear does not hear much energy above 10...and normally it does not hear as well above 10 as it does below 10k anyway...I have my hearing checked regularly and the freq response charts have shown this to be true since my 20s.
That's absurd. The specifications of the two demodulated modulation methods alone shoot down that statement. Moreover, the actual (not revisionist-alternate history) indicate that back in the day, people moved to FM for music because of better quality.
The NRSC 10 kHz audio bandwidth limit was not required until June 30th, 1990.
If you were within 3 miles of a well designed compensated antenna response curve Class IV/Class C station at Night, Motorola sounded great. With 8 mS/m conductivity and 1 kW from a quarter wave tower, this would be around 50 mV/m. I suspect that having a lower Q response electrical height would be better though. WSAM 1400 sounded great, for instance. Heard it playing "I Just Called To Say I Love You" by Saginaw's most famous native, as I traveled though within 3 miles on a Sony SRF-A100.
I wish folks would stop misusing the term audio "bandwidth". Bandwidth should be used to describe the I.F. Bandpass of a given AM tuner/receiver. Remember AM radio is Double Sideband. In the NRSC system, the maximum audio frequency permitted is 10 kHZ for the Upper Sideband and 10 kHz for the lower Sideband. Therefore the bandwidth is 20 kHz. Before NRSC the bandwidth was 30 kHz, allowing an audio frequency response identical to FM (15 kHz). AM radio sounds terrible today primarily because of receiver design , and only secondarily because of increased forms of interference. The AM on my absolutely horrible Kenwood car radio is hideous. The I.F. bandpass might be 3.5 kHz. You literally cannot hear the letter "S" at the end of words. This narrow bandpass may provide near absolute adjacent channel rejection, but destroys any semblance of pleasant listening. It makes all the stations sound the same - Bad! If this type of receiver were my only experience with AM I would wonder why it exists at all! Those of us that have been around the block, though, know very well that with a properly designed receiver with switchable bandwidths, coupled with a properly shaped I.F. bandpass, will sound almost the same as FM. This experience of course is based on the assumption that the station being listened to is broadcasting high fidelity audio.
This. And AM has been long relegated and optimized to being programmed for speaking not for music. Tuner manufacturers gave up on the idea of music on AM starting back in the late 70's early 80's. 'Can you hear Traveler's Information Service broadcasts? Done!'
Sorry for moving this thread off topic a bit, but I really wish Kahn would have been more open to speaking about some of his ideas, explaining more about some of his theories and maybe even teaching younger engineers and imparting knowledge. Unfortunately by the time I got into the radio business, Kahn had by that time become combative, defensive (maybe he was always that way to an extent and it just became more noticeable or was reported on by industry trades more often), he had basically stopped speaking with industry publications like Radio World, was smarting from the CAM-D vs. IBOC vs. C-QUAM battles and seemed suspicious of most everyone.
