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 bandplan, 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.
And if you don't have room for the complete list, here is the big Milcom challenge: These freqs are the biggest Milair unknowns on the planet. if you hear something on these I would like to really hear from you. Try programming these mystery freqs: 233.600 252.300 252.600 277.300 293.900 298.200 336.700 371.400 MHz.
226.2500 234.1750 236.9250 239.0750 244.6750 244.9250 245.0750 248.5250 248.7750 249.6750 249.7250 250.3750 250.4750 250.5750 250.8750 251.6250 251.6750 252.3750 252.4500 252.8750 253.1750 253.4250 254.6250 254.8750 255.0250 255.3250 255.4750 255.5250 255.6750 256.4250 256.9750 258.0250 258.4750 258.5250 259.0750 259.2750 259.6250 259.7750 264.4750 265.3750 265.4750 265.6250 265.8750 266.8250 266.9250 267.0250 267.1250 267.2250 267.3250 267.9500 267.9750 268.3250 269.8750 269.9250 270.0750 270.4250 270.4750 270.9250 271.0500 271.1500 271.3750 271.7750 271.9250 273.8750 274.0250 274.2250 274.2750 274.9250 275.0750 275.6250 275.7250 276.1750 276.5750 276.7250 276.7750 276.8750 277.1750 277.2750 277.4750 277.5750 277.6750 277.7750 277.8750 277.9500 277.9750 278.0750 278.5250 279.3250 281.2250 284.3250 290.8250 292.7500 292.8250 293.0750 293.5750 297.9250 299.4250 302.3250 305.7750 305.9750 306.2750 306.4750 306.5250 306.6250 306.6750 307.7750 307.8250 307.9250 308.2250 308.3750 308.6750 309.1750 309.2250 310.0250 310.1750 310.2750 310.5750 310.7750 310.8750 311.0750 311.8750 313.9500 313.9750 316.4250 316.4750 318.4250 318.6250 318.7750 319.0750 324.2250 324.5750 324.7750 326.3750 326.4250 326.8750 328.3250 328.4750 339.8750 341.8250 342.6250 346.4750 346.5750 348.0750 349.8750 350.1750 352.1250 355.4250 358.7750 360.1750 361.5250 361.6250 363.5750 365.6750 365.9750 367.5750 368.9250 369.3750 373.6750 375.9750 377.4750 377.7500 377.7750 378.0750