I have written a lot over the years on this blog and other media about what I call spectrum holes in the 225-400 MHz range. In brief, a spectrum hole is a legit frequency for assignment based on current channel spacing and the DoD band plan, but no activity/current assignment has ever been heard/found for a frequency. That is a spectrum hole. If you are interested in exploring the world of 225-400 MHz spectrum holes, I have now created this page for those who want to monitor a challenge. And if you hear something or know something about one of these freqs, I would appreciate an email at the address in the masthead. This list is based on monitoring in the United States and its possessions. I fully acknowledge that the frequencies in this list may well be in use in other regions of the world, especially in Europe. The only exception to this rule is UHF Milsat frequencies which can be worldwide in nature.
226.250 234.175 239.075 244.675 244.925 245.075 248.525 248.775 249.675 249.725 250.375 250.475 250.575 250.875 251.625 251.675 252.375 252.875 253.175 254.875 255.025 255.325
255.475 255.525 256.425 256.975 258.025 258.525 259.075 259.625 259.775 264.475 265.375 265.475 265.625 265.875 266.825 266.925 267.025 267.225 267.325 267.975 268.325 269.875 269.925 270.075 270.425 270.475 270.925 271.050 271.775 271.925 274.225 274.275 274.925 275.075 275.625 275.725 276.175 276.725 276.775 276.875 277.475 277.575 277.675 277.875 277.975 278.525 279.325 293.075 293.575 297.925 305.975 306.275 306.475 306.675 307.825 307.925 308.375 308.675 310.025 310.175 310.275 310.775 310.875 311.075 311.875 316.475 318.425 318.625 318.775 319.075 324.225 326.375 326.425 342.625 346.475 346.575 348.075 350.175 358.775 360.175 361.525 365.675 365.975 367.575 368.925 369.375 375.975 377.475 377.750 378.075
Updated 24 July 2019