Specific frequency will vary with location. As others have indicated the USN likes to have much of its comms related to these missions in the 240 – 400 MHz range, mostly below 380 MHz but above 380 is also used. But, the 134 – 144 MHz area is used.
The hardware on-board can cover a much wider range of frequencies. Dependant on block of the aircraft and other variables the exact hardware can be one of several models. Legacy airframes did have the AN/ARC-182 (RT-1250A) but those were all planned for replacement, I think. In general most of the airframes are now (I think) equipped with the AN/ARC-210 for VHF/UHF, specifically the RT-1556(v) or the RT-1824(C). Basic coverage is 30 to 400 MHz, AM or FM. Power output is 23 Watts or less, depending on mode and band. There is a high power amplifier available that runs up about 125 Watts. Certain versions of the ARC-210 can go up to 941 MHz, but I am pretty sure that version is not in the Hornet, I suppose such capability might be in the Growler. Each aircraft has 2 sets of hardware.
Keep in mind that the designator “ARC-210” covers a family of radios, the specifics onboard a platform are identified by the “RT” number, such as RT-1556 or RT-1824. An applied radio on a platform may only include some of the family capability, not “all” of the possible modes/powers/freqs, etc. For example, in the ARC-210 family the RT-1851 has different capabilities from the RT-1824.
The aircraft can be equipped with HF capabilities. The Australian birds have HF as a standard feature.
Reference here:
Google search “MIL-R-29583”, dozens of links to this radio set documentation, be aware of date of publication, this system, and documents, have been updated many times.
Other links:
AN/ARC-210(V) (U)
http://armypubs.army.mil/doctrine/DR_pubs/DR_a/pdf/fm6_02x53.pdf
AN/ARC-210 SINCGARS
AN/ARC-210(V) VHF/UHF AM/FM transceiver (United States) - Jane’s Military Communications
T!
PS, for BMT, the KY58 is not a radio, but rather a secure module that can work with a radio.