Larry Langford is owner of WGTO(AM) and W244ds in Cassopolis, Mich. His commentaries on radio issues such as those facing AM owners are a recurring feature. Read his past articles by searching for “Langford.”
My 2013 Subaru was in the shop for extended work. The dealership gave me a 2018 loaner with a Harmon Kardon sound system.
Of course, the first thing I did was turn on the AM radio to see just how bad it was.
I was knocked out of my socks to hear what sounded like FM! The radio has quality features like HD Radio but the station I was listening to was AM analog, yet it sounded simply amazing. I tuned up and down the dial and noticed the secret to the great sound.
The Subaru/Harmon Kardon premium radio was equipped with an automatic bandwidth control. The stronger the AM station the wider the bandwidth.
I got out my field strength meter and did some driving around. It seems the change point from narrow to wide is about the 2 millivolt level. This matched rather well with what is termed “local” AM radio. My ear tells me the wideband mode must be good to about 6.5 kHz with the narrow mode rolling off fast at the more traditional 3 kHz or less.
Local AM stations transmitting music sounded so good they could compete head to head with FM if radios with bandwidth control radios were more commonplace.
[Read: AM Revitalization, Still Not Getting the Main Idea]
It was a refreshing experience and tells us that even though the FCC will not touch the issue of receiver performance, at least one radio maker has successfully tackled the issue.
Could it be that car radio makers are starting to take a second look at performance on AM?
A look at the manual for the H/K radio makes no mention of the automatic bandwidth circuit but to hear it is to believe it. Now if we can just get the other car radio makers onboard we may find real AM revitalization that you can really hear!
