Sounds like you've been hearing phone patches from E-6B Airborne Command Post and/or E-4B Advanced Airborne Command Post aircraft to a ground site via HF-GCS for the coordination of UHF Wideband FM Multiplexed voice/data circuits. Each of those special UHF (225-400MHz) frequencies has a channel # known as "RF # ___" in order to distinguish it from the multiplexed channels the wideband circuit actually carries.
So to hear the stuff, you'd need to be within range & tuned to the RF Channel pair with a UHF receiver. To intercept the non-secure multiplexed channels carried on the RF channel's subcarriers, you'd need to tune in the subcarriers.