Chicago is certainly no exception to this rule...all of the commercial stations have full-power transmitters on top the Sears Tower or the Hancock, while all of the non-profit, independent community stations are relegated to a power of 100-watts or less,* with antennas usually rigged atop some college campus building.
However, with minimal effort and investment you should be able be able pick up the hidden gems on the dial just as good as the corporate loud mouths.
Step 1 : Are you plugged in??
This seems like common sense, but it amazes me how many people actually don't have an antenna plugged into their stereo at home. While most hand-held transistors and portable boom-boxes have telescoping antennas built in, you almost always have to install the antenna on mini-component systems and stand-alone stereo receivers. Sure, you can pick up "B96" right now, but without plugging in an antenna to your stereo, you probably won't be able to pick up the low-power stations at the left of the dial (aka, the good shit).
Check the back of your system and see if you have wires coming out of the holes marked "antenna." If it's too dark, cramped, or just plain scary back there to look too closely, look for a little, useless-looking white string that is probably dangling on the floor. This little white wire actually serves as an FM antenna, and if you live anywhere within the city limits, it should do the trick. If you don't see one, dig in your closets to find your stereo's original box or owner's manual packet...almost any decent stereo will come with one. (a little black oval antenna is also usually included, but this antenna is used to pick up AM signals)
Step 2: Experiment with antenna placement
FM signals are highly directional in general, and with all of the endless interference possibilities in the city (tall buildings, towers, power lines, etc), reception of weak signals can be very unpredictable. Theoretically, you would want to have your antenna extending as high as possible and, ideally, next to a window. Nonetheless, sometimes just throwing a wire antenna in a heap on the floor will give you just as good of reception. You've just got to experiment with putting the antenna at different spots on the wall or on the floor. Results will vary from building to building, room to room and, in extreme cases, day to day.
Step 3: Take a trip to Radio Shack
If you can't find an antenna for your stereo at home, or the little wire coming out the back just isn't doing the trick, it's time to make the trek to your local Radio Shack. As much as a hate this store (no you can't have my address...i just want some damn batteries!), it's almost always the best place to go for any sort of cheap wiring needs. Here's yet another example, as for the low- low price of $4.29 you can pick up an antenna that will give you good reception in just about any environment. It's called an "FM dipole antenna" and essentially it's just a long wire that splits into two. (click here, if you're to allergic to annoying Radio Shack clerks)
I've lived both in the boonies (30 to 40 miles to the next major town) and in the city, and dipole antennas seem to always work the best for picking up both local and distant signals. However, they're extremely directional and you'll want to experiment a bit (see Step 2) to get the best overall reception.
Or...if you're willing to spend a little more cash and don't feel like experimenting with even more wires on the back of your stereo, you can pick up a powered indoor antenna. These range in price from $10-$100 (check out the "Terk" brand of antennas at Amazon.com) and will give you a bit more signal boost depending on how much you want to spend. I've never tried any of them myself, but it may be worth the investment if you're on the extreme fringe of a station's broadcast range and nothing else seems to work.
Step 4: If all else fails...
When it comes to picking up low-power FM signals, sometimes you'll get just as good of results from that old K-Mart blue-light special radio with foil keeping the antenna in place as you will from a $200 stereo receiver. However, generally a more expense receiver or radio will yield better reception results. While I don't think any Chicago station provides programming unique enough to warrant a serious upgrade to your audio equipment, you may want to keep this in mind if you're a dedicated radio listener and you're in the market to upgrade your sound system. If you're on a budget, don't forget to check out eBay for affordable vintage stereo system upgrades. Some of those cheap old receivers from the 70's seem to get better reception than a lot of the new receivers that cost hundreds of dollars.
Good luck with your antenna hunting and configurations....but remember to be realistic in your expectations. A typical 100-watt community station will only have about a 10-15 mile broadcast range...So, even if you buy a $100 powered antenna, you're still not go to be able to pick up "The Pride of the Southside" (WHPK) in Evanston. However, if you live in Wicker Park, a properly adjusted antenna should allow you to pick up WLUW's signal from Roger's Park.
*WNUR-FM is the one exception...they broadcast at 7,000 watts. However, that figure is a bit deceptive because they have an antenna height of only 100 feet, which is very low for an FM station. Without getting into the technical details and FCC regulations, the height of an FM station's broadcast antenna is just as vital as its overall wattage...so unfortuantely WNUR's 89.3 signal has a bit more bark than it does bite.