LA is a lot different than here.   Reception of KNX is pretty good on the LA freeways, Santa Monica Blvd, etc. Few high rises, no streetcar lines.  Even the high rise apartments on Santa Monica are far apart and set way way back from the roadway.   CFTR reception was bad 5 years ago the last time that I had AM in my car, on St. Clair West - TTC streetcar wires, high rises at Yonge-St. Clair and now the tall buildings span all the way west past Christie St..   But CFTR audio on KISS FM HD-2 is really good and CFTR audio on Tune-in is just as good.  

RadioActive wrote:

On the day KNX Los Angeles switched from an FM simulcast of its AM all news format to all sports, my favourite radio writer, Richard Wagoner, conducted a test. He recorded a sample of an AM signal from the station and a second from its FM counterpart, before they dropped the simulcast. 

He put both of them up on his Internet site and challenged listeners to distinguish between the FM signal and the other band. It's not quite fair - the online quality changes the sound of AM a bit. But it's still an interesting test. Can you tell which sample is from 1070 AM and which was 97.1 FM?

Take the test and answer a few questions about the experience here.

The answer to this L.A. writer's question to see if you can tell the difference between AM & FM contains some surprises, although the number of people who took part was extremely small - and thus not a true representation of anything.

But it still contains some surprises - something the author claims carries lessons for those still running AM stations. 

"In some cities, and it will happen here eventually, owners are turning off the (AM) transmitter and turning in the license because they can’t make money. Would it really hurt for a station — barely surviving and with low ratings —  to at least take a chance on a format that isn’t done anywhere else? Or to do it better due to having more freedom and nothing to lose? It doesn’t have to be expensive — early FMs were run on shoestrings. 

And to further make my point, the last time our local frequencies of 570, 690, 710, 1150, 1190, 1230, 1480, and 1580 had decent ratings, they played music. Just sayin’."

You can see the results of the test here. 

Most of today's car radios receive a very narrow version of the AM / MW signal making it sound tinny and flat. That's not the fault of AM. General Electric made several versions of portable radios called "Superradios". They had a wide / narrow bandwidth selector that adjusted the receiver's filters to produce audio with much better fidelity. The difference in audio quality was striking especially with a strong signal. The audio quality did not surpass that of FM but was surprisingly satisfying especially coupled with the radio's high fidelity speaker. 

Back in the early 1970s, CFRB's off-air monitor feed to the control rooms (they had to listen to off-air all the time, not the console output) was a TRF (tuned radio frequency) receiver that had a 15 kHz audio bandwidth. Given that the transmitter feed was a 15 kHz Bell line, it sounded fantastic. At pattern change time, the night pattern status indicator on the remote control activated a relay in the receiver with a 10 kHz notch filter to get rid of adjacent channel skywave interference.