A Guide to AM Broadcast Band Dx’ing


icom746pro.jpg (15203 bytes)This article is for those who may be new to AM broadcast band (MW band) dx’ing and are looking for some strategies in helping them identify stations they are hearing amongst the noise and interference known as the AM Broadcast Band.

I started out in this hobby back in 1968 living in Central New York where as a teenager I built the Knight Star Roamer kit which was a great little 4 tube radio covering LW to 30mhz shortwave. It was AM only (no SSB or FM), had mile wide selectivity and a slide rule dial which meant you would spend half your time just trying to find out what frequency you were tuned to. I used it for 3 years and then migrated to a used Hallicrafters SX62 which had many tubes and was as big as and weigh as much as a boat anchor. (You can see all my radios through the years on my website, http://www.joecool.org/shortwave_qsl_cards.htm )  It too had a slide rule dial, no SSB and only marginally better selectivity. Maybe it was because of youthful enthusiasm or whatever but I was able to log in 220 AM band stations and 62 countries on shortwave with those 2 radios using a 75’ long wire that my father help me put up. I still recall staying up on a weekend night till 3:00am and looking for and hearing KNX from LA. Wow, I was picking up a station from across the country on AM! Back then it seemed a lot easier to identify stations as most stations had local programming (except for the sports games carried by a network feed) and they played MUSIC. Wow, what a concept. Actually playing songs on an AM station. I say that with tongue in cheek as today it looks like most programming consist of talk, sports or religious shows or infomercials. About the only music you read is Radio Disney which shows up all over the band.

 Back then as I do today I keep a spiral notebook as a log. I record the frequency down along the left, starting with 530, skipping every 4 lines, incrementing by 10. The “bible” of station information was something called Whites Radio Log which I remember came in the back of a magazine which I think was called Elementary Electronics. Whites listed the frequency, callsign, location, etc of the AM stations in the US. Between the “Log” and hints from the program and advertisement using local phone numbers, you could log stations with some ease.

 That was then and this is now. Whites nor that magazine are no longer around. Today we have some stations that id no more often than every 60 minutes. We have endless talk/sports/commercials programs from large networks originating from anywhere advertising products and services with untraceable 800 phone numbers. And a new problem, digital AM which wipes out stations one or two frequencies on either side of it. So what do we use today to help identify stations?

 The Internet. The Internet has a lot of great resources that we didn’t have back in the 1960s and 70s. So although the challenge is harder, the tools we have are more powerful.

The first godsend for helping us identify a station is the FCC web site itself. Their AM Station Query web page is  http://www.fcc.gov/mb/audio/amq.html   and is the main page I go to when I go on a particular frequency. I have never found it to be wrong. I enter the frequency and select LICENSE RECORDS ONLY  from the drop down box and select SUBMIT DATA. It will list all stations on that frequency. It gives you a very good idea what to expect in terms of locations, hours of operation, ownership and the like. It helps me identify the callsign as sometimes I hear only 2 or 3 of the call letters but putting two and two together, I can determine the actual callsign. It is helpful also because it list city and state of the stations. So if it is daytime you can assume you will probably be hearing stations from your immediate area and the database gives you an idea of what you may be hearing. Where I live, during the day, I check the database for stations in NY/PA/NJ/CT as those will be the most likely candidates. At night you can see what possible states you are receiving so you can  have more clues in identifying that unidentified station.

OK, so you are listening to a station and using the FCC database, you have an idea of what it is. You think you caught the callsign but you want to verify the station. Another tool then you can use is the station itself. Many stations now stream live on the web. So what I do is I do a Google search by entering the callsign, frequency and “AM” and if the station has a web site, it will show up. And if you are lucky, they will be streaming their audio on the web. All you then have to do is see if it is the same as what you are hearing live off the air. Just keep in mind that many streams are time delayed by up to a minute so what you hear from the net can be up to a minute late. Even if the station doesn’t have streaming audio, the search results will bring back some sites that will list the type of programming that station carries and other useful information.

Another great tool to use are the DX groups on Yahoo (http://groups/yahoo.com). There are a number of them but the two I have found very useful and friendly are ABDX and DXHUB. Here you can ask questions and get help on almost anything related to AM broadcasting. Plus they are frequented by the actual people who run radio stations so they can give you unique insight and info like when a station may be going off air or when they may be doing a DX test.

Lastly, the site http://www.amlogbook.com/ has a lot of great information including Canadian station information which of course the FCC database doesn’t have. It list stations by frequency, call sign, state, etc.

Before leaving the computer one last thing you can try is to pipe the audio from your radio into your computer and record using the built-in MS application SOUND RECORDER (assuming you are running Windows). Once recorded you can use SOUND RECORDER to slow down the speech which may help you decipher the callsign better. Or you can use the great free audio editing program Audacity (http://audacity.sourceforge.net/ ) to edit and filter out your recording. Some people even use a timer program which starts and stops recording to their computers to try to catch that elusive station while they are sleeping!

Besides the above tools, it also is helpful to known when to listen and on what frequencies. During the day you will hear “local” stations, your general state and region. Since the clearer frequencies run by the powerhouses are the lower frequencies, don’t expect much distance or activity on the low end of the band during the day. On the other hand, to log the locals, go to the upper half of the band. At night the upper part of the band is crowded with hundreds of low power stations. At night it may seem strange but you could have better luck picking up a station the next state over than the local station the next town over. Some of those low power night stations run on just a few watts, I don’t think they are barely getting across the street so I don’t know why they even stay on! But regardless, you will probably find on most frequencies a station you have receive during the day and a different station you receive at night. In my log book besides the callsign, city and state of the station, I record the time and date and what the program content was. So next time I am dx’ing on that frequency I won’t waste time trying to id the same station I tagged before. And don’t forget that those digital stations “turn off” the digital part of their transmissions at sunset so if one of them is obliterates stations next to it (like for me WOR 710 from NYC which blocks out 700 – 730), wait to sunset and try then.

The FCC says stations have to identify themselves once an hour and some stations don’t even seem to do that. And then some stations like WCBS 880 New York City id a few times a minute! The top, bottom and quarter hours are the best time to hear an id. Keep in mind that even the US AM stations that broadcast all day long in a different language like Spanish still id in English at the top of the hour (at least this seems true from my experience). Also, if you can hear a commercial for a local business or a traffic report, try to pick up the address or phone number. For both you can go to Google Map or phone search to try to find the area which may give you more clues as to where the station is.

I believe most DX’ers try to get as many states as possible and at least for New York state, prime hunting ground to snag the more distance stations is the area from 1600-1700hz. There aren’t a lot of stations up there but the ones that are there are quite far away. Since they are clear channels, if you are looking for some new states, check there. And if you can speak French or Spanish, go to 1610hz. The FCC database shows no US AM broadcast stations license there. I hear only foreign language stations and a New York State Thruway traffic alert radio station there!

And just because you have received a station on a given frequency don’t think that you are done. Try that same frequency a few hours earlier or later and you may find some other station coming in readable there. I have received a maximum of four stations on one frequency and at least 2 stations on all other frequencies. The only exception for me are the clear channel frequencies the likes of 650, 660, 700, 710, 770, 880 which where I live are dominated by powerhouse stations on 24/7.

And finally you can get the maximum out of your radio by using these tricks. Of course it depends on your radio so I’ll tell you how I do it with my radio, an Icom 746Pro. First of all, I rarely use AM mode. That may sound strange but on the Icom 746Pro I use USB or LSB. It cuts through the noise and fading great and with the built-in filters for SSB, I can remove a lot of the rumble and fading which makes listening difficult. Also, with SSB, selecting the LSB or USB sometimes puts you far enough away from a local station splatter that you have a usable signal. When I do use AM it is to detune to an off frequency. Sometimes if you have a lot of “stuff’ going on detuning a little bit from the main frequency will allow you to receive the station of interest a little bit better or help you get away from some interference. You can use this method in SSB but unless you have a notch filter the beat tone may drive you crazy.

Propagation changes from season to season and year to year so if you think you can’t find any new stations, check back a few days or weeks later, you may hear some new stuff!

This is a great hobby with it unique challenges. My kids think I am crazy listening to “noise” for hours on end but when I snag that new state or city and outline that state on my wall map, they all come around and admire what a great catch it was!

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