FM DXING: CHICAGO STYLE

(Reprinted from the May 1981 issue of the DX Probe, the predecessor to DX Chicago)

Whether you own a small portable FM receiver, or an elaborate stereo receiving system, FM DXing – Chicago – style, awaits you. In this article, you will be introduced to the basics of Chicago FM DXing. So, when the BCB and SW bands become full of static and your mind begins to sway away from DXing, FM DX may help you to keep active on the radio dials.

In my opinion, FM DXing in the Chicago area presents a challenge to anyone who pursues it. What other metropolitan area boasts an array of FM transmitters on the tallest building in the world? How many other areas have as many tall buildings to block FM reception as Chicago?

Along with the challenges that an urban area presents to the FM DXer, Chicago is unique, because Lake Michigan is just east of the metropolitan area. Just on the other side of the lake are a host of Michigan FM DX targets waiting to be logged! The Chicago area offers many small 10 Watt educational stations to hear, as well. Most of these have coverage areas of about two miles, and secondary coverage areas of at least nine stations continue to be an added source of loggings for this DXer. If you think it is easy to log the complete list of Chicago education 10 Watt stations, GOOD LUCK!

The Chicago FM DX season begins in April and is in full swing by the middle of May. The middle of October, due to the cold Chicago winters, usually marks the end of the DX season; but FM DX can be ha year-round, provided the conditions are right.

My first long-distance reception on the FM band came as a complete surprise. The date was August 2, 1976. There was a good TV DX opening to the Northeastern U.S., but because I had been a TV DXer for at least three years by that date, there was nothing new for me DX-wise. So, I tried the FM band. It was not long before I heard the following, "You are tuned to the Voice of the Eastern Public Broadcasting Network … This is WFCR, Amherst, Massachusetts … 88.5 on your FM dial." That logging was all it took to get me hooked! Now, FM is the band that I still DX the most.

FM DXing certainly has many things in common with MW and SW DXing. There are best times to hear certain stations; you may verify FM reception by QSL; there is even a club, which is specifically devoted to the FM DXer. There are even modes of propagation which enhance transmitted signals. I will now briefly describe the most common modes of reception on the FM band.

Perhaps the most exciting and certainly the most unpredictable mode of propagation is SPORADIC E-skip (Es). As far as distance, Es will provide DX up to, and sometimes over, 1,000 miles. In most cases, Es will not be involved when the station you receive is less than 500 miles. Es is caused by the ionization of patches of the E layer in the atmosphere, which is about 65 miles above the ground. With the cause not exactly known for the phenomena, some speculate it is connected with low-pressure areas and thunderstorms. When considering that Es is most common in the hot summer months, there may be some type of connection, but how does this connection account for Es, which occurs during the winter? Whatever the cause, Es is exciting. But, do not get your hopes up too high – Es reaching the FM band is not particularly common … In 1980, there were only a dozen openings to the Fm band which produced DX catches. Since Es is unpredictable, you must be in the right place at the right time to take advantage of the openings.

About this time, you’re probably asking yourself, "When are Es openings most likely to occur?"

Es peaks in June and July. Very good openings are also in May and August. There are even few openings in late April and early September. Of course, I must mention that there are of-season openings in December and January as well.

Now that you know the times of the year to try for Es … how about the time of the day to try?…

Though Es may occur any time of the day, it is most likely to occur between 8 AM and 11 AM, 2 PM to 5 PM, and 7 PM until 9 PM. It is also noted around midnight. However, late last year, there were several openings noted way past midnight!

A good rule of thumb to remember about Es, is that it travels to the FM band that is situated in TV channel 6. There must always be Es on TV channels 2-5 before it can be noted in the FM band.

The subject of equipment is one that has been debated by many different FM Dxers. In my opinion, you do not need elaborate equipment, or even an outdoor antenna, to fatten your logbook with Es catches. In fact, the majority of my Es catches have been made on a Panasonic RF-1115 with its built-in antenna.

Tropo (tropospheric bending) is the other major form of FM DX propagation. As you can tell by its name, tropo is totally caused by changes in the earth’s atmosphere. Tropo DX occurs along temperature inversions, often associated with frontal passages. It also happens often when a high-pressure area is just ahead of a cold front, especially when there is an influx of gulf moisture. It is most important to remember, however, that the tropo condition is most likely to occur when you are in the most stable area of the weather pattern. The air must be stable for long-distance reception to occur. So, by correlating weather maps with particular tropo conditions, you can possibly predict when tropo may occur three times, or even four times more often during the DX season. There were at least 36 different opening on the FM band during the 1980 season. Tropo can occur any time of the year, but is not as likely during the winter. Tropo can also occur any time of the day, but it is most likely between 5 AM and 10 AM, and 6 PM to 11 PM. Though tropo can be heard on a portable Fm receiver, better results will be enjoyed if you use a more expensive Fm receiver and an outdoor rotor antenna.

Return to Top of Page
Return to Main Page