Tuesday, September 14, 2010

Winter DX Season 2010

Great mediumwave conditions were apparent three mornings ago (September 11). I'm an early riser, and at 6AM I'm usually on the way to the coffee shop DXing on the truck radio. Of course at that time of the morning it's still very dark out. The sun doesn't rise here until 6:40L. Tuning to 850 KHz at the top of the hour news, I caught a nice full ID from 50KW KOA-850, Denver, CO (1420 miles) at 0605L. The KOA radiator, a single tower located 30 miles to the southeast in Parker, CO, is a skyscraping 667.9 ft. tall, almost a full 5/8 wavelength in height. As advertised, KOA gets out to some 38 states, and probably more. KOA began broadcasting in 1924.

Back in the late 1970s and early 1980s, I lived a mere 10 miles southeast of this transmitter, out in the rolling eastern plains of Colorado near the town of Elizabeth. I worked in Denver, and would drive past this tower every day (or night) on the way to and from work, often seeing mule deer or prong-horned antelope. Coming from the east, a long hill descended down appropriately-named Hilltop Road, ending at Colorado Highway 83 which ran past the tower. Headed to work one night for the graveyard shift during a blizzard, at midnight I remember becoming disoriented in the whiteout and losing control while descending that hill, shooting straight across highway 83 and through a barbed wire fence, coming to rest in the field right next to the KOA tower. Ah, memories.

KOA is a tough catch here in western New York with nighttime interference from sports stations WKGE-850, Johnstown, PA  (10KW), at 199 miles, and WKNR-850, Cleveland, OH (4.7KW), at 235 miles. Interestingly, on my cross country trip each year I start to hear KOA at night consistently once I get west of Ohio and into Indiana, and under the 1200 mile distance range. I find there's something brick-wallish about that 1200 mile distance in mediumwave DXing.

WWL-870, New Orleans, LA (50KW), 1136 miles, is also appearing almost daily on the 6AM trip. WWL has a two tower antenna array, oriented south-north with major lobes to the northwest, and northeast. The northeast lobe points directly at me. Each of WWL's towers is a full 1/2 wavelength tall. With 3.3 dB gain in my direction, it pumps a healthy effective radiated power of 106KW right up a pipeline to New York. WWL's transmitters are located approximately 2 miles southwest of Estelle, LA, in the Jean Lafitte Preserve, a wetlands. All that water undoubtedly helps too. WWL has been in operation since 1922, predating KOA by two years.

Apparently the winter DX season is upon us once again.


Greg said...

I think a lot of the apparent 1200 mile limit you've noticed is due to interference from other stations, not propagation.

When I was a kid first interested in radio back in the 1970s, KSL 1160 in Salt Lake City, Utah was a regular catch in Eastern Ontario. Now it's impossible to hear, largely because of the numerous stations that have been added on that frequency. The multitude of co-channel stations means that a weak but listenable signal from across the continent is going to be drowned out by other, closer, stations most of the time. So now the only time we can hear those stations is in the rare moments when their signal strength happens to rise to the point where they can overcome the interference.

Radio-Timetraveller said...

Hi Greg,

Generally, I agree with you - it is an interference thing. I wish I could have been around DXing in the 1920s and 1930s when the radio magazines reported all sorts of routine coast-to-coast DX.

To me, the fading properties seem to be a little different out past 1200 miles. The fades seem deeper and longer, the peaks not quite so high. The chances of hearing a signal reliably are certainly less.

Radio-Timetraveller (Bill)