A long time ago, early in my radio hobby, I learned from a mentor that if I had a $1000.00 budget, it's better to spend $100.00 on a radio and $900.00 on the antenna system. A radio is only as good as it's antenna system. I've seen so many folks buy a "big radio" then spend about $10.00 on an antenna, only to blame the radio. Speaking of antennas, maybe one day, I'll post a picture of my "rolling Ham shack" (my '69 GMC)!
AM radio, being so low in frequency, usually needs a very large antenna, suspended around a large area. I won't go into antenna formulas here, but, the lower the frequency, the longer the antenna, henceforth, usually the better reception. In some cases however, you do not need a lot of real estate to get good reception...enter the "loop antenna"!
This antenna is literally a loop of wire suspended in a frame and can be turned to favor the particular signal one seeks, and to null out the unwanted signal(s). For years, Ham radio operators have built these, using them to receive a station while using a separate transmitting antenna. Shortwave and AM radio listeners have long used them for their listening pleasure, too, and have received more reliable signals.
Building your own antennas (and radio gear) has fallen slowly by the wayside, especially since the 1950's, when ready-made consumer products started rolling off the assembly line. For those who want to chase a better signal, there are ready-made products, at a pretty decent price!
The TERK AM Antenna is one such antenna, usually for right at $40.00. The TERK can either be placed near a radio to "inductively couple" the signal, or it can be plugged into a portable or stereo (with proper connections), as well. Then, it can be rotated for best signal (sure beats trying to slide the home stereo around!).
Also, a ferrite bar antenna of larger porportions is of help, too. Usually, these are much larger than the ferrite bar inside radios. Going even further, there is a Twin Ferrite Bar Antenna available that appears to be an "active" (amplified) version. This latest version uses an AC adapter, which leads me to believe it is of the amplified variety.
Now, just a little commercial here: both antennas mentioned are available from C. Crane Co.:
These folks have been in business for years and sell some very fine products for the radio enthusiast. Give 'em a look...and, if you're an AM broadcast band enthusiast, you may want to invest in either one of these products and enjoy some AM "DX"!
Bud S. (firstname.lastname@example.org)