CLE ARTCC 290.275 - Mil or Civilian?

[eorange]

This afternoon I heard quite a bit of traffic on 290.275. It didn't sound like mil comms, though - no callsigns that I heard, just seemed like routine flight level confirmations.

Is it possible these were mil comms (based on it being a UHF frequency), or could it have been civilian, or both? At least two times I heard a request to switch to a VHF frequency. When I listened there, I could hear both sides of the conversation, but still nothing to indicate that it was mil comms.

Any ideas...?

 

[TinEar]

Erik, ARTCC controllers simulcast their side of conversations on both VHF and the corresponding UHF freq. So, you're hearing the controller talking mostly to commercial aircraft when you hear him on UHF. As you found out, when you switched to the VHF freq, you heard both the controller and the commercial aircraft speaking to each other. If they didn't do that, the military aircraft trying to use UHF would not know the controller is busy with another aircraft on VHF and just start speaking in the middle of a conversation. Considering the low level of military traffic on the UHF side of a Sector frequency, it's not feasible to have controllers strictly for UHF so the same controller handles both.

 

[morfis]

This afternoon I heard quite a bit of traffic on 290.275. It didn't sound like mil comms, though - no callsigns that I heard, just seemed like routine flight level confirmations.

Is it possible these were mil comms (based on it being a UHF frequency), or could it have been civilian, or both? At least two times I heard a request to switch to a VHF frequency. When I listened there, I could hear both sides of the conversation, but still nothing to indicate that it was mil comms.

Any ideas...?

The frequency was probably "bandboxed" (combined) with a VHF one ie. both frequencies are controlled by one desk and simulcast.
The initial contact frequency will likely be band-boxed all the time, other military ATC freqs will be bandboxed at night when there is insufficient traffic to justify having two controllers or if there is some other reason for there being a shortage of controllers.

 

[eorange]

Thanks guys, that all makes sense and is consistent with what I heard.