Hf radios use frequencies in the range of 2 to 25MHz. HF offers reliable communications in remote areas. The two most popular brands of radios are Codan & Barrett. You have to have a licence to operate a HF. Use HF Radios for contacting emergency organisations such as the RFDS VKS 737 Radio Network. Modern HF features allow users to reliably make contact with each other and Base Stations located all around Australia. Modern radios can do Direct Dial Radio-Telephone calls through VKS-737 Base Stations. What is the VKS – 737 Radio Net Work? See our VKS-737 Radio Network Page.