Thursday, April 29, 2010

Radio Silence

Continuing with the search for official government sources of current AM stations on (or off!) the air, I uncovered this gem the other day on the FCC site.

AM silent stations, silent over 2 months

This is a list of U.S. stations which are licensed but silent and off the air for at least two months. As of this writing, the count is nearly 100. And good news, the list seems to be updated regularly. Unfortunately, Canadian and Mexican stations do not appear because this information is not added to their records within the FCC database.

Additionally, this and other useful information like MW stations broadcasting in hybrid IBOC digital format can be garnered from this FCC search page.

This will be helpful information for merging into an overall database.

Wednesday, April 28, 2010

Canadian/Mexican AM Station Search

Recently I have been browsing the web looking for official government sources of current Canadian and Mexican AM stations on the air. Accurate information on who is actually broadcasting is hard to come by in one comprehensive database.


Here in the United States, the FCC's official government database covers not only US stations but Canadian and Mexican stations as well. Web opinion portrays it as notoriously flawed. Part of the problem, I believe, is that the output of the AM Query list is drawn and built from a number of separate databases, many of which have multiple and redundant records for the same station. "Application", "In-Planning", various types of "Construction Permit" records and "Licensed" records, and a smattering of "Deleted" records exist. The FCC saves everything. Slogging through them and deciding which is current and which is not is nearly impossible, even for the FCC. It is a case of too much information. Spending many months weeding out the chaff, I have found the US section to be surprisingly accurate.

Not so for Canadian and Mexican records. They are added to the database, missing information, then forgotten. In past years, broadcasting in Canada has been moving to FM, and year by year, fewer and fewer AM stations remain. This is somewhat true for Mexico as well, and Mexico's AM to FM transition process may speed up even faster with its announcement that it plans on migrating all AM stations to FM in the near future. Deleted Canadian and Mexican stations are almost never pulled from the database. In my experience with the FCC database, some Canadian stations have been off the air for nearly twenty years and are still listed. Hence, this is what drives my search for a more up-to-date governmental database for these countries.


Similar to the FCC's AM Radio Database Query page, I discovered recently Industry Canada's Frequency Range Search page which will output MW radio station data to either a web page or downloadable text file. This information appears to be drawn from a comprehensive database of all spectrum telecommunications across Canada. For our MW interests, one must specify the search criteria, i.e., frequency range (530 KHz - 1700 KHz), and pertinent filtering fields. A multitude of information is available, such as latitude and longitude of station, transmitter power (though only available in dBW), a wealth of antenna information, site elevation, call sign and licensee names, and much more.

How accurate the Canadian government query is remains to be seen. I don't see record redundancies yet. I am hoping that they have deleted inactive station records. So far, that generally appears to be the case, though I have a report of one. A small annoyance is that tourist information stations and low power emergency stations are also included in the output. There doesn't appear to be a filter option to remove them. I'll be experimenting with this data in a program I'm writing that already uses the FCC's AM radio station data to provide comprehensive information for MW DXers like me, such as sunrise/sunset times for distant stations, distance and bearing, competing co-channel stations, relative signal strengths, and a multitude of other interesting info. Since this Canadian database appears to be more accurate than the FCC's, I'll merge it in, eliminating the inaccurate records from the American one, and hopefully provide some needed accuracy in actual stations on the air.


Mexico is another story. I have not been able to find an actual government database file online that documents their AM radio station network. Private sites do exist that attempt to provide lists of Mexican AM stations, but their information is not in a file format which can be read by a third party program. This is what is needed. If anyone has any information on a government site or other site which has compiled the Mexican AM station network into an accurate data file format, I would appreciate knowing its location. The only government list I found available, in .PDF form, is the Infraestructura de Estaciones de Radio AM list. Though the URL address is dated 2008, the actual .PDF retrieved is dated 31-Dic-2009, or December 31, 2009, so hopefully the information is somewhat current. Check the Cofe_radio_y_television page out for additional information.

Monday, April 26, 2010

Cross Country Pipeline - A Daytime MW DX Tale

This is a story about daytime mediumwave DXing. To set up this story, let me tell you that I am on my way back to New York from Arizona, by way of Denver. As usual, I like to DX the mediumwaves on the way, often from my truck radio. There is little but routine DX until I leave Denver headed east on Monday morning, April 19th. Over the next two days I will have some new personal daytime MW DX distance records and an incredible DX experience to remember. And here is the story....


Denver, Colorado. 0900L (9AM). I am headed due east out of Denver on I-70. I-70 snakes through Colorado, Kansas, Missouri, Illinois and onward for the eastward traveller, through the major cities of Kansas City and St. Louis, crossing the Mississippi River at St. Louis. Kansas itself is 425 road miles across and Missouri about 250. The eastern plains of Colorado and west-central Kansas are about as flat as a pool table, and there are basically no trees until you near Topeka, Kansas, closing in on Kansas City, some 625 road miles distant.

To add interest to the trip, I decide to see how far I can hear three prominent Denver stations: KHOW-630 (5KW), KKZN-760 (50KW), and KOA-850 (50KW). 760 KHz and 850 KHz are clear-channel frequencies. I am DXing on a 2006 Ford Ranger truck radio. The truck radio is adequately sensitive and uses a short whip antenna.

160 MILES.
I cross the Colorado-Kansas state line, 160 miles out, about 1300L. All three Denver stations are still powering in, even lowly KHOW-630 at 5KW. No difference in strength can be discerned. Remember, it is daytime, and midday. The D-layer has long since "re-coagulated", and we are well outside the 2-1/2 hour guard zone around sunrise and sunset. It always amazes me why these extreme daytime MW DX distances are common out west, and I rarely see this happen in the east. My fellow Ham buddy Jeff, K3OHU, says it is due to all the clutter in between station and receiver that attenuates the signals. Out west are wide-open spaces. Perhaps he is right. I proceed on, as I plan on driving another 2-3 hours before stopping.

225 MILES.
I pass Goodland, Colby, and Oakley, Kansas, closing in on 300 miles now. The three stations continue to hang in, very strong. I might expect that of KKZN-760 and KOA-850, both 50KW stations, but not of KHOW-630 at 5KW.

309 MILES.
At 1530L, I pull into Hays, Kansas for the night, some 309 miles as the crow flies from Denver. KHOW-630 has weakened some, but is still of medium strength. KKZN-760 and KOA-850 are still powerhousing through the truck's speaker. Somewhere in the last hour I have crossed into the Central Time Zone, losing one hour. Tomorrow, Tuesday, should be interesting, and we shall see what and who shows up in the morning.


309 MILES.
Hays, Kansas. I am up at 0530L and back on the road. It will still be dark for another hour. Intermittent low fog hugs the road, mile after mile. I take a scan around the band to see what's happening. Within fifteen minutes I hear all four sides of the country - the west coast: KFI-640 Los Angeles, CA, the east coast: WSB-750 Atlanta, GA, the northern border: WCCO-830 Minneapolis, MN, and the southern border: WWL-870 New Orleans, LA. Also heard before 0630L and daylight are WGN-720 Chicago, IL, WBAP-820 Dallas TX, KEEL-710 Shreveport, LA, and KOKC-1520 Oklahoma City, OK, all with strong signals. Things are about to get interesting.

350 MILES.
East of Hays, Kansas, and still dark out, the three Denver stations are nowhere to be found, buried, I suppose, under the jumble of nighttime signals on their frequencies. It starts to get light, and I hurtle east across central Kansas, wondering if this will be the end of hearing daytime Denver DX for this trip, as I will soon be out of range.

398 MILES.
Nearing Salina, Kansas, stations to the extreme east are fading away due to the impending sunrise. WSB-750 Atlanta fades, as does WGN-720 Chicago. Popping up on 720 KHz now is a strong signal out of 50KW blowtorch KDWN, Las Vegas, NV. KFI, Los Angeles, holds its own on 640 KHz. I tune to 740 KHz looking for KCBS in San Francisco, expecting something further up the west coast, but nothing. KGO-810, San Francisco, is also absent. Next I tune to 770 KHz - the channel was vacant just a little while ago - and now there is powerhouse KKOB in Albuquerque, NM. I have a quick breakfast in Salina at 0645L, then back on the road at 0730L.

450 MILES.
East of Salina, Kansas, the sun is well up now. A pleasant surprise! Denver's KOA-850 is back in there, alone on frequency. KKZN-760 is in there too, but competing with KCCV-760 (6KW), a religious station in Overland Park, Kansas, near Kansas City. KHOW-630 has not showed.

495 MILES.
I come to Topeka, Kansas at 1020L. The low fog is lifting. It is more than 2-1/2 hours past sunrise and into the daytime DXing timeframe now, and the nighttime skip has totally vanished. KHOW-630 has still not reappeared and I suspect we are out of range for it anyway. KCCV-760 in Overland Park has overtaken Denver's KKZN-760, I figure for good, as KCCV will only get stronger as I approach Kansas City. By then, presumably KKZN will be out of range. KOA-850 hangs in there quite nicely with a nice medium strength signal all by itself.

550 MILES.
I roll through Kansas City, crossing the Missouri River, and on into the state of Missouri at 1135L. KOA-850 is still hanging strong. KKZN-760 is completely obliterated by the Overland Park station KCCV. I press onward for Columbia, Missouri, just past the center of the state, another 120 miles distant.

600 MILES.
Fifty miles inside Missouri at 1220L, the Overland Park station fades, revealing Denver's KKZN-760 again, at a good signal strength. KOA-850 continues to hang fairly strong, still alone. Surprisingly, the signal strength of these two are still respectable through the truck's speaker, and arm-chair copy. KHOW-630 is still absent. I hear a weak religious station creeping in on 630 KHz, probably KJSL-630, St. Louis (5KW), nearly 200 miles in front of me. I am getting close to my personal daytime DX record of 675 miles. Ironically, that is held by KKZN-760. I have received it twice while in southwestern Arizona.

675 MILES.
I pass through Columbia, central Missouri, at 1330L after stopping for a very quick lunch. The excitement is building, as I am now passing my daytime MW DX distance record mark of 675 miles, and I have two stations still in contention for a new record. I can hardly contain myself. To my amazement, Denver's KKZN-760 and KOA-850 are still hanging in with weak to medium signals, well above the noise level. The fades and peaks have become long and drawn out, perhaps 20 or 30 minutes between them, but even the fades are still readable. What gives? I have never heard MW DX signals at this strength at this extreme distance during the daytime. The Denver weather report on KOA indicated fog still on the ground in the Denver area at their 1130 AM local time. I start to wonder if the ground fog is part of this scenario?

685 MILES.
A few minutes go by, then bad news. I start to hear splatter on KKZN's signal. The splattering station, at 770 KHz, is playing a sort of ethnic variety music, so I assume it must be coming from station WEW-770 (reportedly 10KW), located in St. Louis, Missouri. This can only get worse as I close in on St. Louis, and I fear that in time I will lose KKZN permanently to it. To make matters worse, underneath KOA-850 another station appears, gaining in strength. I can't identify it yet.

710 MILES.
East of Columbia, and less than 100 miles from St. Louis and the Mississippi River, I decide to check for WSM-650, Nashville, Tennessee, the famous Grand Ole Opry station. This spring on my trip out it carried well into southern Missouri, down the I-44 corridor. I tune to 650 KHz. There I find a station, weak-to-medium, in the clear. I listen for ID, as the 1400L news is on but I missed the top-of-hour. They give the local weather report. Something about Wyoming and Cheyenne. What is this? No, it can't be! Then the ID comes. "This is KGAB, 650 AM, Cheyenne"!

I can't believe my ears. KGAB near Cheyenne, Wyoming transmits with a power of only 8.5 KW! But there it is with a perfectly listenable signal strength through the truck speaker at an amazing daytime distance of 710 miles! The local time is 1405 CDT, and an hour earlier at 1305 MDT in Wyoming. KGAB is totally in the clear, without side splatter or other interference on-frequency. The thought occurs to me that I'm only about 100 miles from the Mississippi River and the Illinois state line, and I begin to wonder if the two Denver stations and Cheyenne will hang in there long enough to get to the river. I race towards the Mississippi, as things are starting to deteriorate on all fronts.

738 MILES.
The stations are getting weaker. Denver's KKZN-760 is getting hit very hard with 770 KHz splatter, and is almost unreadable now. KOA-850 is almost totally covered up with co-channel interference. I identify the offending station as KFUO-850, coming closer by the mile, in Clayton (St. Louis), Missouri. Little KGAB-650 in Cheyenne, Wyoming is weak but still readable, and in the clear. The fades take it totally out, then it re-emerges for several minutes at a time. The Glen Beck program is on. It started after the news at 1400L CDT. 54 miles to the river. And one hour. I've got to do something.

I pull off the exit at Warrenton, Missouri, thinking I will attach a four foot length of wire to the truck antenna and let it trail in the wind while I drive. I've used this technique before to gain some signal strength and pull in distant DX. I attach the wire and continue on down I-70 towards St. Louis. Signals are marginally better, but the 770 KHz splatter is killing KKZN-760, and KOA-850 has finally disappeared under St. Louis's KFUO-850. Wyoming's KGAB-650 hangs in there, barely.

792 MILES.
Traffic builds as I approach the river. The only station left is KGAB-650. It is right at the noise level. At exactly 1505L I cross the Mississippi. Just over the bridge I faintly hear Glen Beck say a few words just above the noise level - what, I don't know - but I can recognize his voice. Then - gone. KGAB fades below the noise for good.

800 MILES.
I am in Illinois. To the left of me I pass two AM radio stations. One has an array of four towers and the other six. The receiver desenses so badly that it overloads. I press on wondering what will happen next.

827 MILES.
Pocahontas, Illinois. It is 1545L time. Hurriedly, I pull off the exit and into the motel parking lot where I will stay for the night. After registering, I check the truck radio again. Surprisingly, 760 KHz is clear of splatter - but nothing but noise is heard - and no KKZN. 850 KHz is occupied by St. Louis's overwhelmingly strong KFUO. Weak but steady, 650 KHz plays the country music of Nashville's WSM. KGAB-650 is gone, forever.

Quickly I grab the Tecsun PL-600 out of the truck and tune to 760 KHz. I put the headphones on. Something is there just at the noise level, but what?

In a greater hurry, I dig for the 24-inch passive loop I constructed this winter. The PL-600 is still two feet from it when the signal on 760 KHz comes right up out of the noise, nearly arm chair level in the headphones. It is Progressive Talk Radio, KKZN-760, Denver, Colorado! Unbelievable! A new personal daytime mediumwave DX record of 827 miles! Imagine hearing the front range of the Rocky Mountains - some 36 miles east of the Mississippi River in Illinois - IN THE DAYTIME!


KKZN-760 (50KW) Denver, Colorado to Pocahontas, Illinois: 827 miles
KGAB-650 (8.5KW) Cheyenne, Wyoming to I-270 & Mississippi River: 791 miles


Who knows how far into Illinois I could have heard KKZN-760? With the interference from KCCV-760 gone, its signal was still respectable off the 24-inch loop at the town of Pocahontas, some 36 road miles east of the Mississippi River. My guess is another 50-100 miles, closing in on 1000 mile daytime DX!

What makes the difference in long distance daytime DX? Clear co-channels and clear adjacent channels are very important. Flat, unobstructed terrain I'm sure is important too. Ground conductivity is very important. Ground conductivity from Denver to central Missouri ranges from 15-30 millimhos per meter. From central Missouri eastward to the Mississippi River it drops to 8, then rises back to 15 east of the Mississippi River. Did partial fog along the distance also make a difference? Possibly, but I will never know for sure what effect it had.

It is remarkable what a 24-inch tunable, passive loop will do for a signal seemingly buried in the noise at 827 miles distant. I was astounded.

KHOW-630, Denver, CO 5KW News-talk
KKZN-760, Thornton, CO (Denver) 50KW Progressive talk
KOA-850, Denver, CO 50KW News-talk
KGAB-650 Cheyenne, WY 8.5KW News-talk

KJSL-630 St. Louis, MO 5KW Religious
KCCV-760 Overland Park, KS 6KW Religious
WEW-770 St. Louis, MO Variety/ethnic music
KFUO-850, Clayton, MO (St. Louis) 5KW Religious