The radios come from the factory blank, so they'll need to be programmed. The dealer should be able to program them for you. If you already have existing radios in use, you'll need to make 100% sure the new radios are programmed -exactly- the same as the old ones, or they may not be able to talk to each other.
If you are only purchasing a few radios, it will likely be cheaper to have the dealer program them. A good shop will be able to help you make good decisions about the many, many programmable functions these radios have. There is a lot more to it than just programming in the frequencies.
I don't have any online vendor recommendations, I've always purchased via local shops.
As for the power supply, you'll need a 15 amp 12 volt regulated power supply. Not difficult to find on the internet. Just make sure you get a good name brand. There are companies that produce power supplies that have a mount integrated for specific model radios, it makes life a bit easier, but isn't necessary.
As for base antennas, this is where a local shop can really help you out. The exact antenna you need depends on a number of variables, and having someone with specific knowledge can be valuable.
-The antenna will need to be specific to the frequencies you use.
-Deciding on the antenna gain is something that takes some skill and knowledge about the local topography. Picking a random antenna could result in reduced performance. Transmitter power out + your antenna gain - feed line losses all figure into something called Effective Radiated Power, and this is something that is limited by your FCC license.
-Antenna mounting is very important. The height of the antenna will directly affect your system performance. Low to the ground and coverage will be very limited, higher up will provide wider coverage area. Go to high up, and you may start interfering with other uses on the same frequencies outside your area, or picking up too much interference.
-Coaxial cable is -very- important. You need high quality cable, properly installed, and that's all dependent on how/where the antenna is mounted.
-Lightning protection needs to be considered, and is mandated by the National Electric Code, as is proper grounding.
While it will add to the overall cost, getting the system properly designed will greatly reduce frustration and issues down the road. This really is one of those places where investing a few hundred bucks in professional services now will save you thousands later.
Both the portable and mobile radios will support voice inversion scrambling. It's very basic and not terribly secure, but will provide some limited security from very casual eavesdropping. If you need something better than that, you'll have to change radio models.
