jon wrote:
"This isn't as far-fetched as many of you might think. While the U.S. and Canada chose to limit themselves to 50,000 watts, the Havana Treaty, and its replacement, allow 250,000 watt AM stations. Mexico still has one fully operational on 900 KHz in Mexico City."
In northern Europe, a number of high powered MW and LW stations running 100-200 kW are still on air. Most have been shut down in favour of FM - a much cheaper way to serve small communities. However, none of these countries face the challenge of vast regions with sparse populations, as we do in Canada's north. While it makes sense to replace the 40-watt AM LPRT's with FM signals in settlements such as Fort Simpson, Fort McPherson, Tuktoyuktuk etc, it doesn't address the issue of serving the remainder of the population with CBC's Radio 1 or Radio 2 services. Having driven Alberta's Hwy 35 as a trucker twice in the early 90's, I was amazed at the daytime coverage from CKHL High Level running 1 kW on 530 as I drove north to Yellowknife. CFYK 1340 also had good coverage. That got me thinking that high powered AM would be a great way to get daytime signals throughout the north. Now that Radio Canada Int is no longer on short-wave, I've recently mused on AM as a means of providing northern service.
"I often wondered about a one to two million watt directional station on 530 KHz positioned somewhere along the 60th parallel, with no signal to the South. Two things to think about:
the Yukon, NWT and Nunavit make up an area almost as large was the four Western provinces, even when you don't count the islands in the Arctic Ocean"
I don't think 2 million is required to do this. Multiple frequencies using 250 kW spaced strategically throughout the north would do the trick. I'd really have to do some serious mapping to figure out best locations for this. Not only would 530 be a great choice, but use of 690, 860, 940 or others is fair game. Many of these have been in use in settlements with one-time or current AM LPRT service and are now 'in the clear'.
"Northern Lights are a frequent occurrence and apparently kill all skywave reception, and may also produce some background noise for groundwave reception, so you need solid groundwave coverage everywhere you plan to serve. I also understand that there are ways to design AM transmitters to increase skywave propogation, so assume there must be ways to reduce it. Doing that with some sort of synchronous high powered repeaters on the same frequency may solve the problem of serving such a large area."
This makes for a good argument using high powered AM to provide good night coverage as well as day signal. As mentioned, this has served northern European countries quite well in the past. European companies Brown-Boveri and Rohde-Schwarz are experts at designing & implementing high powered arrays & have been responsible for building these monster Euro MW & LW signals for many decades now. Their highly complex antenna arrays are designed to deal with ground-wave irregularities and auroral-induced anomalies. There are plenty of pics on various broadcast history sights showing these magnificent antenna systems. We're talking very expensive, high-end solutions - a factor that makes this discussion highly interesting as a technical topic but a total disaster as a practical solution for the CBC. Satellite internet access or Sirius XM are available to isolated residents and mobile users alike. Still..it's fun to speculate and as more attention is focused on "saving the AM band" this is the one idea I could come up with as Canada marches on with "AM to FM flips"
