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Tuesday, June 12, 2012

RADIO-TIMETRAVELLER Maps #3

1 Watt At Night - U.S.

1 Watt At Night - U.S.

The ultimate DX. How good (or lucky) a DXer are you? Have you ever tried for extremely low power AM stations at night?

Every night, 15 stations across the U.S. transmit with an output power of only one watt. How far does one watt travel normally, let's say under static conditions during the daytime? I'm glad you asked.

One watt into an omni-directional antenna (1 tower), over medium ground conductivity (8 mS/m), will get you out 10 miles, at which point the signal enters the "fringe" area of reception (0.15 mV/m and less). A good receiver will hear somewhat farther than that. At night, and using a directional pattern, who knows how far that signal will travel? All things are possible.

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CallSign       Freq    Power Class Location                     
-----------------------------------------------------------
WCKB            780        1    D  Dunn, NC                     
WRFM            990        1    D  Muncie, IN                   
WHFB           1060        1    D  Benton Harbor-St. Jo, MI     
KLEY           1130        1    D  Wellington, KS               
WGAB           1180        1    D  Newburgh, IN                 
WSQR           1180        1    D  Sycamore, IL                 
WPGR           1510        1    D  Monroeville, PA              
WENG           1530        1    D  Englewood, FL                
WJJT           1540        1    D  Jellico, TN                  
KBOA           1540        1    D  Kennett, MO                  
WBNL           1540        1    D  Boonville, IN                
KLKC           1540        1    D  Parsons, KS                  
KDYN           1540        1    D  Ozark, AR                    
WZRK           1550        1    D  Lake Geneva, WI              
WSRY           1550        1    D  Elkton, MD

Here's some statistics for our 15 one watt stations, taken from the 5-27-12 FCC database:

All 15 are Class D.

12 are located east of St. Louis, 3 are west of St. Louis.

KLEY-1130, Wellington, Kansas, is the most westerly, leaving no 1 watt stations from there all the way to the west coast.

11 are "W" callsigns. 4 are "K" callsigns.

The 15 stations broadcast using 24 towers.

11 stations broadcast an omni-directional pattern (single tower). 4 broadcast a directional pattern (multi-tower).

1 station is on the FCC "Silent" list: WZRK-1550.

Interesting to note: 5 of the 15 are on the same frequency - 1540 KHz.

The lowest powered daytime station in the FCC's database broadcasts with 135 watts.

The most interesting broadcast pattern is that of WRFM-990, Muncie, Indiana. This station broadcasts using 6 towers. Its pattern projects generally to the north, covering Muncie and Delaware County as shown in the radio-locator graphic. WRFM-990's daytime power is 250 watts.

Sunday, June 10, 2012

Mexican AM List Updated Once Again

Just a head's up. Mexico's Federal Telecommunications Commission "Cofetel" has published the official Mexican AM station list in .PDF form again. The list is dated May 31, 2012. This is starting to become a regular thing of late, as the last update was just two months ago. Kudos to them!

Get the list at the Cofetel site.

Don't be mislead by the 2008 date in the site link. After downloading the PDF, you can find the actual list date at the bottom of the document.

This list can be made into a nice spreadsheet form by converting the saved PDF document to an XCEL (.XLS) file. If you don't have the software to do that, a great, free online conversion site can be found at Zamzar on the web.

Viva Mexico!

Wednesday, May 23, 2012

RADIO-TIMETRAVELLER Maps #2

50 Kilowatts Night - U.S.

50 Kilowatts Night - U.S.

Our next map depicts all 50 kilowatt stations broadcasting during nighttime hours in the United States. 98 stations are represented. Black flags indicate allocations in the nighttime service class, pink flags the unlimited service class (24-7). The FCC defines service classes as DAYTIME, NIGHTTIME, UNLIMITED, and CRITICAL HOURS (the first two hours of daylight after sunrise and the last two hours of daylight before sunset). Data is from the 4-24-12 FCC database.

Representative antenna pattern plots are also shown.

Here are the statistics.

59 stations are Class A. 39 are Class B. 0 are Class C. 0 are Class D.

50 are located east of St. Louis, 48 are west of St. Louis.

51 are "W" callsigns. 47 are "K" callsigns.

The 98 stations broadcast using 269 towers.

30 stations broadcast an omni-directional pattern (single tower). 68 broadcast a directional pattern (multi-tower).

1 station is on the FCC "Silent" list: WDCD-1540.

If we divide the western hemisphere MW broadcast band in half (the center is at 1115 KHz), we have an equal number of MW channels below 1115 KHz and above 1115 KHz. There are 31 nighttime 50KW stations broadcasting above 1115 KHz. 67 broadcast below 1115 KHz.

Monday, May 21, 2012

Mediumwave DX Meets The Tablet Computer

A previous series on this blog talked about the wealth of information we mediumwave DXers have for listing stations, and ways to reference it in the field. Last year about this time I bought an eReader (a Nook Color), with the idea of using it to read books and other saved documents. What I discovered was how easy it was to create customized station lists from various web sources using my laptop, then transfer them to the eReader for reference in the field when DXing. The second part in that series talked about using the eReader for displaying DX lists.

After a summer's use it became apparent that a tablet computer might be an even more usable device, as it would allow better web access, more options for file reader software, and a bigger screen (10 inch vs. 7 inch). This spring I purchased an Asus Transformer TF101 Android tablet. It has been a good choice.

As mentioned previously, typical station lists can be created in several forms using various web or other sources. Reader apps for tablet computers can handle .TXT (text) file format, .PDF (Adobe's Personal Document File) format, .HTML (web) format, and others - even .XLS (XCEL) spreadsheet files or comma-separated value text (.CSV) files.

Three favorite web sites of mine for mining mediumwave AM data are Lee Freshwater's AM Logbook, MWList, and the FCC's AM Query. Let's review what they have to offer.

AM Logbook will generate a single web page list of stations by frequency, callsign, state, city, transmitter location, and others. US and Canadian stations are represented. The page can be saved locally by your browser and transferred to your tablet through either a hard connection, WiFi, or a Cloud service like Dropbox or Box. AM Logbook also supplies its AM list in downloadable XCEL spreadsheet form.

MWList, a more complicated site, attempts to document all AM stations worldwide, by country. It encourages users to register, but its data is also available to non-registered users. MWList has the ability to create a customized country file in PDF form which is then made available for your download. This is really the way to go on this site. Enter the site, login if you are a member or click "Continue as guest", then click the "Downloads" heading tab. Check off the countries desired, then download your PDF file. Transfer to your tablet as indicated above.

MWList also outputs country data to a generated web page, like AM Logbook. Country data is initially displayed by frequency, but the data columns on the page can be click-sorted by location, callsign, state, etc. Data is presented in an HTML "frame" within a parent page, so saving the web page core data in this way is not as easily done. Sometimes it is necessary to break the frame out into its own window, and this is the technique that I use. Some browsers allow this option and present a right-click menu item to accomplish it. Firefox and Opera include this function. Once the frame is broken out into its own page it is easily saved as HTML. Text formatting is maintained this way.

Data from both AM Logbook and MWList are based on a variety of sources, one being actual reception reports. Canadian data seems accurate for both, as it is not drawn from the FCC database. Ditto Mexico and other countries for MWList.

The third option, the FCC's AM Query, can also be used to create a station reference file. US data should be highly accurate, but be suspicious of any foreign data. You would be better off with AM Logbook or MWList for Canada and Mexico or other countries. Output can be displayed as a simple web page or a text file, easily transferred to a tablet, as above.

My own Radio Data MW program has the capability of creating station list files in HTML and CSV formats. I often use its files on my tablet, as I can set them up to show expected signal strengths and sunrise/sunset times for each station, something not available with any of the other sources.

Much reader software (in the form of apps) is available for the tablet. Adobe Reader (free) and ezPDF Reader (less than $5) are good ones for displaying PDF format. Your tablet already has text reading software and an HTML browser, though many others are also available for free through the Google Play Store (previously known as Google Marketplace). Apple's iPad has similar software available at their App Store.

An advantage to staying with the HTML format for your AM list is the tablet browser's pinch-to-zoom function. With file sizes fairly large, and long line lengths, it is advantageous to be able to zoom the text smaller and larger. Most PDF readers have the pinch-to-zoom capability, but not all work as well as the web browsers. Basic text (.TXT) reader software doesn't always have an appropriate zoom capability, or may wrap long line lengths causing confusion. HTML is the better choice here.

Tablet batteries typically last 6-10 hours, more than enough for a casual afternoon or night of DXing. All tablets seem to have sound recording capability, and most have video and sound recording, both. Thus your device can also be used to create a record of your DX catch for personal record or verification purposes, an added bonus to owning a tablet.

Turn your tablet device into a mediumwave DXer's station reference!

Viewing a MW database on a tablet