Marine VHF radio Channel Information
The obvious difference between marine VHF radio and other analog radio is that all channel frequency points are non adjustable and are fixed frequency points, and some of these frequency points are the same frequency points and some are different frequency points. This leads to many friends in the use of marine VHF radio can not effectively direct. The following is a brief introduction to the channel of marine VHF radio, hoping to help some friends.
Don't say much. Go straight to the picture above. As can be seen from the figure, the marine VHF radio has 88 channel numbers for communication, including the same frequency point and different frequency point channels. The reason is that there were not so many early maritime interphone channels, only 28, that is, 01-28 channels. Subsequently, some channels were added to meet the use needs at sea and on board. Such as ch60, CH80, ch01a, ch05a, etc. Some of these additional channels have the same frequency points and some have different frequency points, so it leads to some difficulties in the use process. Here's a simple comb.
It can be seen that all channels with letter A, such as 01A, 03A, 05A, etc., are co frequency channels. There are also co frequency point channels, such as CH06, ch08-17 and ch67-77. That is, two marine VHF radios can be directly connected in the same channel. The rest are different frequency channels. The transmission and reception frequencies of these channels are different. Therefore, to make a call, the transmission and reception frequencies of the other party need to be exchanged before normal communication, such as CH01, CH04, etc. There are also five special channels,. Why is it special? It is because these five channels can only receive and cannot transmit, namely ch21b, ch25b, ch28b, ch83b and ch70. The first four channels with subtitles B are used for broadcasting and dispatching in the coastal center, and there is no need for intercom reply on the ship. Ch70 is a special distress alarm channel. Generally speaking, it only has the function of receiving voice, but does not have the function of sending voice. Through this introduction, I want to explain the channel of the marine VHF radio basically, what interested friends can do with their own intercom.
