Your VHF Radio System how healthy is it? Can you rely on it when it counts?
Your VHF Radio System isn't just the radio it includes the wires that connect the radio to the battery, the coax cable ( that's the wire that connect the radio to the antenna), the antenna , microphone and speaker. All the parts must work together to provide a reliable communications system. Lets start with the radio. Where is it? It should be easy to get at and out in plain view. There no point running below to yell “Mayday” if the boats on fire or trying to contact help in a man over board situation. A good location for a radio is at the helm or within easy reach of the helmsman. The speaker should not be covered or obstructed you should hear each message clearly. So you can act accordingly. If the radio is mounted away from you add an extension speaker. The microphone should be clean , the cable in good condition with no cracks or fraying. A dirty or damage microphone can distort your voice so no one will recognize what you are saying. The wires to the battery should be large enough with clean solid connections to provide full battery potential to the radio. A voltage drop caused by poor connections or inadequate wire size will drastically reduce the transmitting power or even shut down the radio. If the wire is more than 10 feet long to the battery , a 12 gauge wire is recommended , if its 20 feet a 10 gauge, if more than 30 feet 8 gauge .These wire sizes are approximate and to be used as a general guide . Terminal lugs used to connect to the power should be crimped and soldered. The connections must be tight and clean with no sign of corrosion. The battery should be in good condition topped up with distilled water and all cells healthy. A charged healthy battery should read 12.8 volts and not change much when the PTT button (push to talk) on the mic is depressed (HI power). The only true test of a batteries condition is with a Hygrometer .It is used to test the condition of the acid in each cell. All cells should measure the same if one cell is dramatically different replace the battery. The coax cable and antenna can only be tested with a specialized meter that looks for a standing wave .This standing wave indicates the amount of reflected power the coax & antenna does not radiate into the air. That does not stop you from inspecting the connections they should be clean and secure. If you have just bought a new radio because the old one was performing poorly. I suggest you install it as if its the first radio in the boat. Don't use any of the old system. The fault might not have been in the old radio. Old coax cable might look good but the cable can deform at the mast head . Over the years it had to support the cable weight an the insulation can be compromised. The antenna might have been subject to a static discharge from a near by storm and no longer operates properly. Here again corroded connections will compromise the radio performance. A new antenna and coax cable will cost around $100.00 and might have been all that was needed. You cannot use TV coax cable for the VHF radio nor can you use the Loran or CB antenna for the VHF radio. If you are not sure of your VHF communication system get it inspected and tested, you might have to rely on it for that call for help.