For the best use of multi-band transceivers, many amateur radio operators will run various aerials with stepper switches for various bands and switch between them when necessary with a physical antenna switch. Operator Dan Zimmerman also does this, but after creating a remote-control solution for his rig for use while away - he needed a way to control the switch as well. Not a problem - with an Arduino, a motor capable of turning the physical switch, and some interesting circuitry Dan can now change remotely via the Ham Radio Deluxe software. It's a clever system, that can self-align the switch position on power up, and read the location of the switch by reading the value of an attached potentiometer.
If you're making a similar project and need to control large currents and voltages with your Arduino digital outputs - you'll need a MOSFET. We've got you covered with out NDRIVE: N-MOSFET driver/output module:
This high-power N-MOSFET module lets you switch high-current loads using a tiny microcontroller. Perfect for controlling that set of traffic lights mounted in your living room! Works brilliantly for automotive projects such as switching high-power 12V lights and high wattage LEDs. For more information and to order, visit the product page.