I just noticed that Blinq.com has a “New – Open Box” Terk AM-1000 Advantage indoor mediumwave loop antenna, on sale for $27.69. This is a great price for this quality AM loop which typically sells for about $50.
The antenna (much like the Tecsun/Grundig AN-200) inductively couples to your AM radio. In other words, simply place your radio next to the antenna, tune to your desired frequency, then tune and turn the loop antenna until you maximize your received signal. Very simple to use.