The 28MHz (10m) amateur allocation spans from 28-29.7MHz. Being this large, there is room for all speech and data modes including AM and FM. In my opinion it is the very best band for amateur radio operation. It is good for both DX and local communications and requires only simple antennas and low powered equipment. If you've never tried 10m operation you've missed some great fun.
In sunspot maximum years the 10m band is often wide open for world-wide DX even with QRP power levels and when using the simplest of antennas. At most other times in the sunspot cycle it is open to somewhere in the world during daylight hours although DX is more usually found on the N-S paths rather than E-W. In the quieter years DX may be hard to find due to lack of activity rather than poor conditions. Monitoring the various 10m beacons gives a useful indication of propagation. The usual modes for DX working are USB and CW. In addition, data modes such as PSK31 are becoming increasingly popular around 28.12MHz.
At times, most propagation modes are possible on the 10m band. Most DX contacts are via F2 layer propagation although short skip Sporadic-E is a propagation mode that frequently brings unexpected contacts at high signal strengths especially during the early summer months. Sporadic-E contacts usually range from 300-1000 miles although multi-hop sporadic-E is quite common. Even in sunspot minimum years this can result in transatlantic contacts from Europe to the USA in summer time. It is not that uncommon for multiple modes to be possible. A summer sporadic-E opening can join up with F2 propagation at lower latitudes and some amazing DX then becomes possible when least expected. Another useful mode is aurora which can support DX out to about 1000 miles in higher latitudes at times of auroral disturbances. On 10m auroral contacts on SSB are possible as the phase distortion is less severe than on the 6m or 2m VHF bands. Finally good old tropo openings can support extended local communications up to several hundreds of miles. This can bring surprise range extensions when operating 10m FM mobile for example. Tropo openings on 10m are often at their best around sunrise.
FM operation is centred around 29.6MHz which is used as the calling frequency. Although when the band is not open this is used by many as a frequency to chat on it is courteous to move off this frequency once contact has been established in much the same way that 144.3MHz is used in Europe. There are numerous 10m FM repeaters around the world. These use a -100kHz shift and input frequencies start around 29.5MHz. 10m FM is especially ideal for local communications as ranges up to 25-30 miles are possible with just a few watts to a mobile vertical whip or CB 1/2 wave vertical. DX operation using FM can be fun although the QRM level can be high at times unless you spot an opening at a time when few others have. Many people use converted CB equipment which is inexpensive and in many cases not hard to adapt to 29MHz operation.
10m is one of the few bands on which AM operation is quite common. The band is wide enough to accommodate AM signals that would just not fit on many lower frequency bands. Look between 29-29.1MHz for AM stations. Often AM operators are using lovingly restored AM transmitters that date back to the 1940s, 50s and 60s. The modulation is frequently superb. Listening to 10m AM is like entering a time warp: this is how amateur radio sounded in the 1950s and 1960s when I first became interested in shortwave listening.
10m WSPR Beaconing
WSPR is a recently introduced mode that is perfect for QRP beaconing. I have only tried the mode briefly on 10m so far, but as propagation improves during 2010, this should be an ideal mode to check propagation and to experiment with truly milliwatt or microwatt transmitters. To check WSPR activity you will need WSPR2 software and to tune your rig to 28.1246MHz in USB, Already this mode has shown openings to Europe, FR and V51 that would not have been detected using more conventional modes.
10m is an ideal band for homebrewed equipment and antennas. A simple VXO controlled 500mW QRP transceiver with few parts can be built "ugly" style on a piece of copper laminate in a few hours. A basic 1W VXO controlled transmitter may be built in 30 minutes. Such rigs are capable of working thousands of miles and are enormously satisfying to use. Similarly, a small direct conversion transceiver is not much more difficult. At low power, DSB is a perfectly acceptable mode to use on 10m and there have been several circuits published. Simple verticals and beam antennas are easy enough to fabricate using readily available metalwork from the local DIY shop and can be erected without help, if care is taken.