Wideband AM Radio

[MHVRadiofan]

Recently when The New York Times sold it’s long time Classical music station WQXR to a non-commercial organization ,they gave a history of the station before signing off on the 96.3 frequency . Among the innovations used by the FM stations predecessor WQXR- AM was the use of ‘wideband AM’ for better sound quality . I believe the station was on 1560 AM . This of course was many decades ago. I was wondering what wideband AM was/is . I am not a professional , just a radio junkie.

 

[KeithE4]

Recently when The New York Times sold it’s long time Classical music station WQXR to a non-commercial organization ,they gave a history of the station before signing off on the 96.3 frequency . Among the innovations used by the FM stations predecessor WQXR- AM was the use of ‘wideband AM’ for better sound quality . I believe the station was on 1560 AM . This of course was many decades ago. I was wondering what wideband AM was/is . I am not a professional , just a radio junkie.

Before NARBA (1941), the AM band only went up to 1500 killer-cycles. There was some experimental wideband (20 kHz channel spacing) transmissions starting in 1934, and WQXR was one of them, under the call letters W2XR on 1550.

There were four of them on the air between 1934 and 1941, with 1530, 1550, and 1570 kHz allocated to this (experimental) service. No station ever used 1570 AFAIK; an application for that frequency in LA was rejected by the FCC.

On 3/29/41, all four stations became commercial broadcasters with "normal" AM facilities:

W1XBS 1530 Waterbury CT became WHBY 1590 (later WQQW, now silent).
W9XBY 1530 Kansas City became KITE 1550 (now silent).
W2XR 1550 New York became WQXR 1560 (now WQEW).
W6XAI 1550 Bakersfield CA became KPMC 1560 (now KNZR)

Link: Jeff Miller's History Site (look almost at the end of the page)

 

[radiorob2.0]

The quality continued. Before pattern change I could hear WQEW (then W2XR) in wideband AM Stereo during the Adult Standards days. The sound was smooth and full compared to other AM's at the time that sounded tinny and harsh.

 

[radiolistener66]

Thanks, KeithE4! I've been working in radio for 43 years and this is the first I've heard of "Wideband AM!" At the risk of dipping my toe into a technical area I'm only vaguely familiar with, I still wanted to chime in.

Years ago I had worked at a number of AM stations down in the 540-800 kHz range and was aware of what seemed to be the "narrowing" of AM channels progressing up the dial. Back when the 50,000-watt station on 540 in Orlando (what is now WFLF and was previously WGTO) was a music station, I remember thinking that it sounded as good as an FM signal (albeit, without stereo). But I also wondered whether it was just my imagination.

Were the 1934 AM wideband experiments successful in demonstrating better audio quality? Or did the clamor for AM channels back then supercede the issue of audio qualilty? In other words, did commerce win out over quality?

Or did the experiments simply show that the difference wasn't enough to warrant cutting the number of available channels in half?

 

[FreddyE1977]

my best guess on the answer is that since it could deliver even greater fidelity and was static-free, wideband was simply overtaken by the emergence of FM

 

[davideduardo]

On 3/29/41, all four stations became commercial broadcasters with "normal" AM facilities:

W1XBS 1530 Waterbury CT became WHBY 1590 (later WQQW, now silent).
W9XBY 1530 Kansas City became KITE 1550 (now silent).
W2XR 1550 New York became WQXR 1560 (now WQEW).
W6XAI 1550 Bakersfield CA became KPMC 1560 (now KNZR)

Link: Jeff Miller's History Site (look almost at the end of the page)

You can find lists of all stations from that era at http://www.davidgleason.com/Radio_Archives.htm

 

[Tom Wells]

I recall hearing in radio school (1980) that WGAR Cleaveland had some kind of authority for a special wideband mode in the 1970's, but it wasn't Kahn stereo...Is anyone aware of any official tests of "beyond 10khz" modulation?

I do recall this station sounding incredibly good and huge in the mid 70's.

 

[FreddyE1977]

Around 1980 I started being able to receive WGAR at my home in Pittsburgh. I assumed that they had made some
sort of technical change at that time but have no idea what it was. Can't get them now thanks to IBOC splatter
from 1250 WEAE,

 

[Dave-N2DS]

Here is a scan of the W2XR qsl card that my father received in 1935.

Here are some other old time qsl cards: http://www.makearadio.com/qsl/index.php

Dave

 

[jhguthlac]

I went to the web site to view the QSL cards. Nice collection!

I, too, was unfamilar with wide band AM.

 

[rtc]

Before they had FM,the so-called Apex AM wideband system was tried

on 11 meters and such:

http://en.wikipedia.org/wiki/Apex_(radio_band)