The PRC77 radio operates on 30.000 to 75.95 MHz. If the Harris radio operates on any of the same frequencies (I know you said it's VHF, but VHF covers 30 to 300 MHz), then it can.
By using a VHF radio.
They communicate by two-way VHF radio.
No, they cannot.
history of vhf radio
You need a VHF radio antenna, a VHF radio receiver and of course a station broadcasting on the VHF frequency.
VHF is in the range 30 to 300 MHz.
Because VHF signals have a line of sight limitation.
While both use high frequencies that are line of sight range only, the cellphone connects to a cellular network of transceiver antenna towers that are interconnected (via either landlines or microwave links) permitting cellphones at practically unlimited distances to communicate. VHF radios can only communicate when they can "see" each other (or both can "see" the same VHF repeater).
VHF radios work by the line of sight principle
Very High Frequency.
VHF radios work by the line of sight principle
Personal Floatation Device for each person aboard