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UHF CB channel 35 has been reserved as one of the two emergency channels, but why is it even more important to avoid channel 35? Let us try and explain.

When you use a UHF CB repeater (also called range extenders, or duplex) your radio actually uses two different channels for receive and transmit. The channel you select (1 to 8 or 41 to 48) is called the “receive” channel – it’s the channel the repeater station transmits on and that you receive or hear the repeater.

But, when you press that push-to-talk button on your microphone (on channels 1-8 or 41-48), and you have repeater mode turned on, the radio automatically transmits 30 channels higher, which is the channel the repeater hears your transmission.

So, what does this mean?

UHF CB emergency repeaters use two channels – channel 5 (your receive channel), and thirty channels higher, channel 35 (the repeater’s receive channel). Any signal on channel 35 will be automatically re-transmitted over channel 5, whether you realise it or not.

Using channel 35 for general chat can block an emergency repeater you didn’t even know was there, because you won’t hear it. But, everyone else trying to listen to the repeater output channel (5) will hear you, and others that may be trying to use the repeater to call for help may be blocked if your signal into the repeater is stronger than theirs.

Repeaters are usually located on top of tall mountains or buildings, so often they can “hear” much farther than you can. A repeater could hear your signal on channel 35 long before any ordinary monitor or other CBer can, and if the monitor/CBer can’t hear you then you won’t hear them trying to tell you it’s an emergency channel.

Even worse, during certain atmospheric conditions, a UHF CB signal can travel hundreds of kilometres, meaning you could block an emergency repeater you may never normally hear.

So, to put it simply, PLEASE, don’t use UHF CB channel 35 as a chat channel! Read more about the emergency channels.

Image credit: CREST Victoria.