The general freq range for UHF military satellites is about 245 to 272MHz FM and searching in 5KHz steps will land on all frequency plans. Most in-the-clear stuff I hear is between about 260 and 265MHz and 99% of all UHF satcom is encrypted but you will hear various groups pirating the satellites and speaking Spanish or Portuguese. There is some occasional brief testing in the clear and the ultra rare cases when US personnel come up in the clear by mistake. I use a tunable receiver (Icom 7100) and search in AM mode, which is easier to uncover signals than searching in FM. At best a Discone will be frustrating as most signals will be extremely weak and you will miss a lot of potential comms. I have used yagis, crossed dipoles, helix and every kind of military satcom antenna and my best luck is with a home made “egg beater” antenna designed for amateur satellite work. I scaled the dimensions for UHF satcom freqs and with a pre-amp at the base, it gives great signal strength and doesn’t need aiming. You would have to be an experimenter and handy with tools to whip one up but I could probably locate the dimensions if you are interested.
UHF mil satcom is geostationary and I don’t know why someone would need a satellite tracking program as mentioned in another post. Good luck, it’s very satisfying to catch a signal that has come from so far away.
prcguy