The Medium Wave or AM broadcast band occupies the
frequency range of 530 to 1600 kHz in North America and has recently been
expanded
to 1700 kHz. AM channels are spaced in 10 kHz increments, i.e. 530, 540, 550,
..., 1600 kHz. Outside of North America channel spacing is in 9 kHz
increments. With the band expanding to 1700 kHz there are some new DX
opportunities before many new stations fill that band segment. A station such
as WJDM 1660 in Elizabeth NJ can be easily heard most nights in Southern
Ontario. See Extended Band List
Medium wave broadcast frequencies fall into
three basic categories. These are clear channels, regional channels, and local
channels. Clear channels are easiest to hear and are occupied by a few strong
stations while at the other end of the spectrum, local channels have many low
power stations on each frequency and are more difficult to DX.
Clear Channels
Clear channels are the frequencies 540, 640-780, 800-900, 940,
990-1140, 1160-1220, and 1500-1580 kHz. These are typically populated by the
50,000 watts powerhouses. On each frequency there are usually only two or
three of these stations across North America making DXing them fairly easy.
Most of the clear channels also have a few lower power stations but they are
not much of a problem unless one happens to be near your location. Old timers
will remember when clear channels really were clear and had only the powerful
signals.
Regional Channels
These chanels are all of the remaining frequencies except for the local
channels which we'll discuss next. Regional channel stations are usually 5,000
watts or less although some now have 10,000 watts. A few stations on these
channels are licensed for 50,000 watts. Once you have logged the clear channel
stations your next goal might be to try the regionals. Because there are more
stations here, a directional antenna can be a useful addition to your shack
when trying to sort out the DX.
Local Channels
Local channels are the frequencies 1230, 1240, 1340, 1400, 1450, and
1490 kHz. These are often called the "graveyard" channels owing to
the odd mix of sounds you will hear at night with so many stations interfering
with each other. These are the most challenging channels to copy because
stations are usually under 1000 watts, sometimes well under 100 watts at
night. Special receiving techniques, a good directional antenna, and a quality
receiver will help in sorting out these stations but even then the process is
a challenge.