I understand that without repeaters, VHF/UHF reach out maybe 10 miles plus or minus, depending on antenna height on either end. With repeaters on towers, maybe 20 to 30 miles is typical. In undertand that starting with 6 meters and lower frequencies (HF) our signals can start to bounce off atmospheric layers and reach hundreds or thousands of miles. Here is my question. How common is it for communities of ham operators who may be involved in Skywarn or ARES, or even independent operators, to set up systems where the VHF/UHF only hams (those who don't possess HF capabilities) have arrangements with other hams who have HF capability to reach beyond the VHF/UHF distance limitations? Is this done on a personal level, i.e. merely communicating with a local ham with HF capability and asking him to communicate to another state? Or are there more sophistated arrangements involving mixed band repeaters? For example, instead of repeating in the same VHF/UHF frequencies, HF repeaters are used? Looking at the band plans, it appears this would only be feasible CW in the CW frequencies so that Tech licensees could access HF repeaters. This capability would be helpful in the case of a region wide disaster affecting most of a state or several states.