Difference between Fixed VHF radios versus Handheld radios
The reach of a two-way radio is largely dependent on the output power of the radio. This is measured in watts. As an example, a typical fixed mount radio outputs at 25 watts and is good for a range of in excess of 50 km unobstructed. Handheld radios typically transmit at 5 to 6 watts and are therefore good for a range of 12 to 18 kms. This is only a rough measure as other aspects affect the effective range of a VHF radio. The antenna type, design and length will have an effect on range.
As with all wireless devices, radio waves can be interrupted by hills. I call this shadowing, much like a shadow from the sun. If your radio is situated behind a hill or other obstruction, then the radio waves will be interrupted and communications may not be clear. Moving further away from the obstruction will typically bring you out of the shadow and communications will come back. A longer antenna will help with this to a small extent.
Another advantage of a fixed mount VHF radio is that they are powered by your vessels electrical system and therefore is generally less likely to be interrupted. A handheld radio runs on rechargeable batteries and you will need to ensure they are regularly charged for effective operation. One could also argue that a handheld VHF radio on board provides a good backup for your fixed mounted unit. If your electrical system goes down, then your handheld VHF radio will operate stand-alone.
Fixed VHF Radios are easy to install. They just need a 12V power source and an antenna installed.
Handheld VHF radios have the advantage that the radio goes with you if you get thrown out or fall off your vessel . It is recommended that you have a backup handheld radio that you have tethered to your person or keep in a grab bag. A grab bag is a waterproof carry bag easily accessible if need to abandon ship in a hurry. Typical items you would keep in a grab bag apart from a handheld VHF radio would include a knife, flares, a personal location beacon, a torch and anything that could aid your survival and assist with your rescue.
