If you are interested in exploring the world of 225-400 MHz spectrum holes, I have them listed on my Milcom Monitoring Post blog. Here are links to all six parts.
http://mt-milcom.blogspot.com/2006/08/milair-spectrum-hole-list-part-1.html
http://mt-milcom.blogspot.com/2006/08/milair-spectrum-hole-list-part-2.html
http://mt-milcom.blogspot.com/2006/10/milair-spectruim-hole-list-part-3.html
http://mt-milcom.blogspot.com/2007/01/milair-spectruim-hole-list-part-4.html
http://mt-milcom.blogspot.com/2007/03/milair-spectrum-hole-list-part-5.html
And the final part just posted this morning at:
http://mt-milcom.blogspot.com/2007/08/milair-spectrum-hole-list-part-6.html
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. 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.
73, have fun and good hunting.