Mexican Governmental Mediumwave List Updated

About a month ago, the Mexican government finally updated their official mediumwave station list, now dated June 30, 2011. Updates to this list do not come very often, perhaps every year or so. The previous list was dated December 31, 2009, 18 months ago. It's been a long time coming.

The list, in .PDF format, documents station location (city and state), owner, call sign, frequency, daytime and nighttime powers, and license expiration date or status. It is unfortunate that actual latitude and longitude coordinates of transmitter sites are not included. However, latitude and longitude can be extracted from the matching entry in the US FCC database if you look carefully and wade through the huge number of redundant and outdated Mexican records to find the right one. I am working on creating a combined list using my Radio Data MW program. That will allow the creation of a list in many forms, sorted at will by call sign, frequency, power, location, signal strength, etc.

To my knowledge, Mexico does not maintain an internet downloadable, official database in file form like the FCC or Industry Canada does. It would be nice if they did.

Mediumwave DX Meets the eReader

We have seen how to create personalized station lists at no cost in the first installment of this series. We can even create a file system of antenna pattern plots. But, as stated, who wants to print all of this and haul it around, not to mention the expense of all the paper and ink?

A couple of ideas come to mind. Save the desired station lists and pattern plots to a flash drive, then take it and our laptop to the field where we will have access to the information. But even a laptop is cumbersome to haul around when you are already carrying radios, headphones, loop antennas, wire, etc. And a laptop generally only has a battery life of a couple of hours before it is dead.

A number of years ago I toyed with the idea of loading text files on a PDA (Personal Data Assistant) device, like a Palm Pilot. There were ways to do this at the time, and you had to be a bit of a geek to figure it out. My idea was to load station lists and other textual documents for reference in the field. But upon further examination, it seemed like reading text on such a tiny device with poor screen resolution was not the way to go. I resisted, waiting for technology to advance. It did.

The dedicated ereader device appeared. At first they were cumbersome to use, and extremely proprietary - having almost no support for anything but books. Finally a couple of years ago the market shifted directions. Manufacturers had at last gotten the word that the public wanted some versatility in their ereader. Text files and .PDF files became compatible and well-supported, along with a host of other common file types like HTML, images, and video.

And with that direction change came the Kindle 3 by Amazon and the Nook Color by Barnes and Noble. I bought a Nook Color. It cost $250. Natively, it will display text files and HTML files, as well as .JPEGs and other image formats. It has a marvelous .PDF viewer. Most of these modes have zoom capability, making viewing easier. Amazon's Kindle 3 ereader device has similar features, though getting .PDFs and text across to them is a little quirky. Tablet computers also abound today, like Apple's iPad2 and the Samsung Galaxy. Virtually all have the ability to handle these same file types.

So, we are set. What we will do is load our saved station reference files to our ereader device. The 7-inch Nook Color ereader is small, the size of a paperback book, and thin, hardly 1/2 inch thick. It is ultimately portable, and can be carried easily wherever we want to go.

The ereader with its 8 gigabyte memory can hold the entire US mediumwave station reference if we choose, and many times over. And that includes the antenna pattern plots if we elect to save them too. No paper, no ink. It can be carried anywhere. Its battery life can be 8 hours (Nook Color, LCD display) to almost a month with one hour per day of reading (Kindle 3 or Barnes and Noble Simple Touch, both e-ink displays). Files are usually searchable. This means that you can locate a frequency or station call sign or format or whatever you are searching for quickly. Not as easy with a 500+ page paper volume.

The only requirement is that we come up with some sort of way to arrange our mediumwave files in an organized fashion so we can have quick access to them. Easily done.

Some ideas on file arranging:

1. Create folders named by frequency or by frequency block (range) to hold station files.
2. Create folders by state name to hold station files from that state.
3. Create folders by city name to hold station files from that city area.
4. Name the files themselves to include call sign and frequency to aid in recognition.

Our master copy folder and file scheme can be created on the laptop and housed there for safe keeping. It will be a simple matter of transferring the master database over to the ereader by dragging and dropping files or folders from one unit to the other when the ereader is cabled to the laptop through the USB port.

For those that have tablet computing devices instead of dedicated ereaders, the procedure would be similar. I am convinced the ereader or tablet device is the way to go for taking mediumwave station lists to the field. Give it some thought.

Also see: Mediumwave DX Meets The Tablet Computer

Mediumwave Station Reference Lists

I DX a lot outside, whether on the road in a vehicle or just to be outside and away from the extreme household noise that we find today. Whether you be a mediumwave DXer, shortwave DXer, or DXer of another kind, the problem in DXing away from home has always been the lack of ready DX reference materials nearby. You have to pack and carry all that stuff. And I like to travel light. My outdoor DXing is often casual and spur of the moment, with a ULR or portable. Who might that weak station be under KHOW-630? I need a station reference.

At minimum, a reference guide of stations helps you to know what to look for and what to expect, so it is important to have one close by. In recent years there were two common radio DXer guides in bound-book form, the World Radio TV Handbook (WRTH) and Passport to Worldband Radio. I used to buy them faithfully every year. Passport had a great radio review section, but its station reference only covered the shortwave bands. Passport also folded last year and ceased publication. It was a great shortwave guide.

WRTH covers longwave to 30 MHz and also FM and TV, listing nearly every broadcast radio and TV station a country has. Unfortunately, its US mediumwave coverage is not complete, in that it doesn't cover many lower powered and graveyard stations. The information is scant, basically only station addresses, power, and antenna type. The recent list price: $35.00 per issue, though it can be had at a discount later in the year. That's a lot of dollars for a little bit of usable information if you are just interested in mediumwave.

The National Radio Club publishes its AM Radio Log every year, and it's a winner. The current, 32nd edition of the log contains some 300 pages in 8.5 x 11 inch size, 3-hole punched, in U.S. loose leaf format. Current cost is $20 for members and $26 for non-members.

The NRC also publishes an Antenna Pattern Book, helpful in determining which direction stations are favoring in their broadcast pattern. The current, 6th edition (late 2005 data) is 238 pages containing both daytime and nightime patterns for stations in the US, Canada and parts of Mexico. It is in the same format as the AM Radio Log, and is designed to be used as a companion to it. The "book" fits in a 1 inch three ring binder. The current cost: $17 for members and $23 for non-members.

We are starting to accumulate a lot of paper (500+ pages so far). And the cost is going up. As you can see, reference guides can be expensive to buy. They also go out of date quickly. Thirdly, they can be heavy and take up a lot of space. We are back to the packing and carrying problem.

In the article, Radio Station Databases 101, we explored several countries' mediumwave databases which might help us in creating our own lists of mediumwave stations to aid us in our DX quests.

However, database information is not generally in a readable format. In most cases it is hundreds or thousands of lines of incomprehensible textual data. It is mainly useful to the software hobbyist who might want to write a database program or create an XCEL (.XLS) file to display station information in various sorted forms. This is obviously a highly technical and tedious endeavor which most people are not equipped or trained to do. My own project in this area is the Radio Data MW program. I will write more on this project at a later date.

Thankfully, a number of web sites exist which have done much of the work for us, tabulating this data and presenting it in one form or another which can be useful as a reference. These web pages, or in some cases, files, can simply be printed and placed into a binder of some sort, then used in your shack or carried to an outside DX location and used there. We have at least saved cost, though not paper.

Let's explore what's available for free on the web.

Pre-eminate in the field, the FCC maintains an AM Query web page that utilizes and searches its standard database for all US stations - AM, FM, and TV, as well as Travelers Information (TIS) stations. I have found the FCC information for US stations to be highly accurate. Be wary of Canadian and Mexican information. Much of it is either redundant or out of date. Properly used, the FCC AM Query will output a large text file of all MW stations.

Opening the web page and selecting the dropdown boxes, "Authorization type: Licensed Records Only (Daytime + Nighttime" and "Output-- AM Short List (or AM List)", then clicking the Submit Data button returns a huge list of active stations. Save this to a file, print it, and you have the entire US mediumwave listing. But it is huge, some 8 megabytes in some cases. You can also search by frequency or state, thus you can create customized lists, saving and printing them.

The FCC also makes antenna pattern plots available. Virtually all stations with multiple towers have directional patterns and the FCC makes this plot available in PDF form. Once displayed in your browser, this PDF can be saved to a file for future reference. Pull up the page for the station of interest to get to the pattern link. Example: WWKB-1520 facility and WWKB-1520 pattern.

radio-locator.com, a favorite site of mine, also has an advanced station search page. Many of us think of radio-locator only as the site that shows us mediumwave antenna pattern plots. The great thing about their page is you can also plug in parameters to filter stations by frequency or state. You can even search by broadcast format. Results are returned in formatted HTML pages. Save the resultant pages to file, print them, and create your own database of stations.

As just stated, radio-locator.com is another site which produces antenna pattern plots. These particular plots depict the expected signal coverage area of the mediumwave station over a map. The pattern plot is displayed as a GIF image. Once displayed in your browser, this GIF can be also saved to a file for future reference. Example: WWKB-1520 pattern.

am-dx.com is a simple textual site that tallies all US stations by frequency. Canada and Mexico are also available. Pick a frequency, display the list, save it, then print it.

The AM Logbook by Lee Freshwater is another interesting site that lists stations in a myriad of ways. Frequency, call sign, state, city, sites (transmitter), slogan, etc. Again, select your preference, display the list, save it, then print it. US and Canadian stations are represented.

AM Logbook also provides its current AM database in spreadsheet (XCEL) format. You must of course have an XCEL (.XLS) viewer. You'll find the link on the Updates page.

Topaz Designs is a basic textual site with search box, returning results by frequency, state, power cutoff (100W), and broadcast format. US and Canadian stations are represented.

Mediumwave List is a comprehensive site that offers a lot of information, including transmitter mapping, logbooks of users, and station news. Worldwide mediumwave stations are represented, including of course North America - Canada, Mexico, Cuba, the Caribbean, etc. To create your station list, login if you are a member or click "Continue as guest". This site will also allow you to download files from their huge database of stations, by region or country. The output is in PDF form. Registration is required for certain information beyond the basic.

Outside of the US, the Mexican government provides a very nice list of their mediumwave service in PDF form. Australia provides a list of their mediumwave service in XCEL form. Using the Industry Canada site, you can search the Canadian mediumwave service and create various lists in text, HTML, and XCEL form.

Note that most of these sites return station lists in a web page (HTML format) versus a simple text page. Lists can be saved as a web page by the Save As function in your browser. But there is also another way. It is possible to select the important data on the web page, copy it to the Windows clipboard (CTRL+C), then paste it into a text editor (CTRL-V). The text can then be saved as a text file, which may require a little editing. Sometimes it is easier to read this way. If you go this route, be sure to use a text editor that supports Unicode text format, like Window's Wordpad, Notepad++, etc. Window's Notepad does not, and you may get a jumble of text with no line breaks.

So, we have several options available for saving and/or printing station lists. We have two options available for saving and/or printing antenna pattern plots. If you choose to print some or all of these and place the pages in a binder of some sort, all well and good. But a comprehensive list of the entire US database is still a lot of paper to store, pack, and carry around. Of course we could just save all these files to a laptop and take the laptop with us. There is also one another option.

Next up: Mediumwave DX Meets the eReader

Also see: Mediumwave DX Meets The Tablet Computer

The Field Strength Machine

What do professional broadcasters and the FCC use to measure the field strength of a mediumwave station? Let me assure you they don't use charts and graphs like we hobbyists do. Let's find out.

What appears to be the premium device on the market today for field strength measuring is the Potomac Instruments PI-4100 Medium Wave Field Strength Meter, available from Potomac Instruments of Frederick, MD, and shown in the photo just above. It is Potomac's "third generation of precision survey instrumentation intended for the direct measurement of electromagnetic field strength in the 520 KHz to 5.1 MHz frequency spectrum."

This meter has a laboratory quality radio frequency voltmeter, a calibrated, Balanced Loop antenna, an internal GPS receiver, an internal calibration source, and data acquisition hardware and software. The unit weighs in at about 5.5 lbs. It is the successor to the previous industry standard, the FIM-41 meter, also by Potomac.

Also included in the 4100 is a spectrum display. Sensitivity is phenomenal, from 22 µV/m (microvolts per meter) to 50,000 mV/m (millivolts per meter). And there is no "meter" as with old units; everything is indicated digitally and calibrated automatically. The on-board GPS indicates your current coordinates as well as the distance and bearing to the station. It even includes a "wet" compass. For more information, see the Radio World product survey.

Oh, what I wouldn't give to spend a day with one of these. What is the price, you ask?

A cool $14,975. You can pick up a used one for about $13,000. Or, you might be able to buy a second-hand FIM-41 for about $5,000, or rent such an older unit for $595 per week. I can only dream.

The older, Potomac Industries FIM-41 unit: