We (maybe just I) got off on an AM radio tangent in the Biggest Concerns in an SHTF Situation thread. Rather than continue down the tangent in that thread, I thought a separate thread may be better.

Good AM radios are readily available, but in some the AM antennas are rather weak and only good for receiving local stations. My Panasonic RF-2400D has a pretty good AM antenna and overall is a pretty decent receiver, but other small AM radios need help. One of the sites I visited in my quest to get education on better AM antennas was/is:
AMANDX AM Loop Antenna Calculator (by Bruce Carter).

What exactly is a loop antenna??? Think of the loop windings as an inductor which provides for area to capture the AM signal. The capacitor tunes the inductor to the AM frequency of interest so that it resonates and becomes a functioning antenna. Those are my words, but the concept is really simple.

I found an appropriate (365pF) capacitor on Amazon (also available on eBay) and 18ga wire is readily available at HomeDepot; an old wooden wine crate was in the garage gathering dust — ~14”x10” with room for 18-24 windings so that became my platform cool

According to the AMANDX calculator it should cover from ~500-2600 kHz w/ 18 windings and ~362-1900 kHz if the number of windings is increased to 24. Since the AM band is 530-1710 kHz, either will probably work. A 100’ spool of wire will give me 24 turns (4’ per) so I can do the higher turn count with no splices.

I may tweak the wire spacing, but for the wine-crate platform and the given capacitor, 18-24 windings seems to be a design constraint. That antenna will be for inside, I’ll use a plastic storage-crate to make another larger antenna for outside.

So how does your AM radio connect to the antenna? Induction. Place your radio next to or inside the crate, that’s it.

All that or you can just buy a Tecsun AN-200 AM... Radio Antenna
Quote:
The Kaito AN200 AM Medium Wave Loop Antenna is a passive (NO power requirements) radiant device that works by either placing it next to the portable radio's internal AM rod antenna or by connecting it to larger desktop radios that have AM antenna terminals by using the included 1/8" to bare wire cable.
The best location to get the signal better is in the center of the beautiful ring...

— It’s about learning.