The other day I posted about the University of Pennsylvania’s N3KZ linked repeater system. Penn’s system is far from unique, even in PA. Going to Repeaterbook.com lets you find the linked repeater systems for your state.
As I mentioned earlier linked repeaters are not a full substitute for an HF rig and NVIS, but they may be a useful tool in the event of an emergency. Many repeaters have emergency power, and many of us live within range of multiple repeaters. For example, from my home, I can directly hit two N3KZ repeaters which are geographically dispersed. The closest one is in the Roxborough neighborhood in Philadelphia, while the other one is near Robesonia, in Lebanon County. They are about 30 miles apart. I’m also able to hit repeaters in AllStar and WAN networks. Some repeaters may be linked to more than one link network. E.g., W3WAN in Roxborough is connected to both the AllStar and WAN networks.
Linking is done largely over the Internet. If it’s full-blown TEOTWAWKI obviously you cannot depend on the ‘net. However, in a lot of SHTF situations you can. For example, on 9/11/01 I was able to communicate with family members on Long Island via AOL Instant Messenger even when phone lines into the NYC metro area were unusable.
In an emergency a lot of communications are done by hams over VHF and UHF. If you have a VHF/UHF rig, I encourage you to program as many nearby repeaters into is as possible, especially if they are linked.