In the last few days, the discussion of the seemingly endless stream of AM to FM flips, has turned several times to: Is BCB/MW/AM DX dying as a hobby? Perhaps it was said best in an e-mail I received a couple of weeks back from a close friend and fellow 1960s DX'er here in the Canadian West. He questioned my sense of buying a decent DX receiver and amplified tuned loop antenna with this clear trend of AM stations migrating to FM.
But a caveat first on the comments that follow. If either my friend or I believed that digital radio was going to replace traditional AM and FM in the way that it seems to be in most of Europe -- a forced march similar to what we see with HD TV in the U.S. -- then I wouldn't be saying any of this. Because the likely effect of the forced march would be reassignment of the AM band to another purpose. And that purpose could very well make AM DX impossible. For example, if cordless phones (or anything equally popular) suddenly moved back there. As a trivia note, that is where they started: in the nose bleed section of the standard broadcast band as we know it today. Somewhere in the area of 1630-1700KHz. BEFORE those frequencies were added to the AM Broadcast Band. AND AFTER those frequencies were taken away from Ship to Shore and a few old technology Police Departments (I listened to the Pasadena Police in 1964 in that band).
Quite frankly, I think AM DX will grow more interesting, not less, if AM stations continue to move to FM. I went through the mental process myself back about 1970, as a AM-only DX'er in my late teens. At the time, the FCC was supposedly seriously considering forcing all AM stations in the U.S. to move to FM within a short period (5 years?). Canada and Mexico showed no sign of following suit, nor did the rest of the world.
As a DX'er, I couldn't have been happier, except perhaps if Canada had followed suit. From my DX Den in Burnaby, I knew that, without KING-1090 in Seattle, I could be listening to XERB-1090 24/7 in the winter, and perhaps even more of the year. I'd never had a chance to test high noon reception of a station that far away that was that powerful -- XERB was only 50KW, but with a strongly Northern directional pattern to try and hit Los Angeles as hard as possible, especially daytimes with KNX-1070 and KRLA-1110 both 50KW only 20 KHz away. In an era of lousy selectivity on most radios.
The foreign (i.e. - non-US/Canada) DX possibilies seemed endless. The old U.S. 1-A Clear Channels were only protected in North America. Which meant that Central American stations like TGJ-880 in Guatemala might have been possible with a very good directional antenna back in the days when only WCBS New York was on the frequency, except on those few nights when reception from the South was good but not from the East. Once the 1-A became 1-B (mid-late '60s) with the licensing of a station in Nebraska on 880, TGJ was only a pipe dream except late Sunday nights when both WCBS and Nebraska were off the air for transmitter maintenance.
Of course, the biggest benefit of AM going dark in Your Town would be the lack of local stations to interfere with your DX. For example, I'm about five and a half miles from CFRN-1260. At night that means I get the equivalent of 100KW in my direction, as CFRN protects KYA San Francisco. If I want to hear anything besides CFRN or its slop from about 1200-1320, I have to use a tuned loop. And I have to tune it to about 1100 or 1450 before CFRN or its co-channel interference disappears. I would get a lot stronger signal on 1300 KHz if I could tune the loop to 1300, rather than "detuning it" to 1450.