Elmer Series - PROGRAMMING THE BAOFENG UV-B5 - 1

PROGRAMMING THE BAOFENG UV-B5 - 1

Programming the Baofeng UV-B5 from the keypad and radio menu system is relatively easy and can be accomplished without using PC software [edit]like unlike[/edit] some of the other Chinese radios.

To understand why we are programming the radio with the settings we need to understand how a repeater operates.

A repeater is a radio system that retransmits signals that it hears.  There are two distinctively different repeater types, simplex and duplex.

We’re not going to discuss simplex repeaters in this post other than to say they listen and transmit on the same frequency and therefore have to record the received signal and then retransmit the signal when the received signal stops. The simplex system takes twice as long to send a message than a duplex system.

The duplex repeater is more complex to setup and requires special equipment which increases the cost.  However, it is the more popular system because it retransmits the received signal as it’s being received.

In order for a duplex repeater to work it needs to operate using two frequencies, one to listen to the received signal (repeater input frequency) and one to re-transmit the received signal (repeater output frequency). 

In the US the difference ( repeater offset) between the repeaters input and output frequencies of the most common repeater bands are as follows:

• 6 meter (50MHz):  500kHz (negative offset)
• 2 meter (144MHz): 600kHz (positive or negative offset depending on repeater output)
• 70cm (440MHz): 5MHz (positive or negative offset depending on local conditions)

 The repeater offset can either be shifted higher (positive offset) or lower (negative offset) from the repeater output frequency.  For the 6 meter (50MHz) band the offset is usually negative.  For the 2 meter (144MHz) band the offset shift is based on what the output frequency is.  For the 70cm (440MHz) band the offset shift is determined by local conditions.

Because local interference or even a distant signal under the right conditions can interfere with the repeater causing it to transmit when it shouldn’t, most repeaters are set up to not transmit unless they also receive a special signal.  The most common special signal used for this purpose is called Continuous Tone-Coded Squelch System (CTCSS).   

CTCSS is a sub-audible (can’t be heard) tone that is transmitted along with the voice signal and when the repeater hears the correct tone it will retransmit the voice.

So now that we know the basics of how a duplex repeater works and some of the settings (output frequency, repeater offset, offset shift, CTCSS tone) that enable us to use a repeater system, let’s move on and discuss how to program these settings into the Baofeng UV-B5.

Elmer Series - PROGRAMMING THE BAOFENG UV-B5 - 2