[genewitch]

They will use separate bands for regional "nets", the net controllers will forward any necessary information to whoever is the regional emcom person, and that person will get the message out over the 28.540 (or whatever winlink frequencies.)

28.540 has the benefit that you can push it rather far on a modest antenna -at any hour - much like CB, and with digital modes you don't need to be able to "hear" it to copy and send copyable text. Most regional nets will be on VHF, UHF, or NVIS HF (the 3.5, 7, etc) depending on the conditions and time of day.