[chirp_users] # of Channels

r norris rkmr15203 at yahoo.com
Sun Sep 2 13:32:15 PDT 2018



> On Sep 2, 2018, at 15:39, clark prather <harpzilla at gmail.com> wrote:
> 
> When I program my Baofeng I have 129 Memory Channels for different Frequencies. If I had a million Memory Channels, how many could I fill for 2 meter?
> 

The last time I messed with it, there were 73 repeater “pairs” (input-output frequencies) on 2 meters.

There are a number of simplex frequencies. These “channels” have been coordinated with the ARRL and local repeater groups throughout the country and world.

Go poke around  on arrl.org <http://arrl.org/> and read about “Band Plans”

Channels or memory is just a term the radio world uses to say what radio frequency will be received or transmitted by the method your radio “remembers” that function and type of signal.

Each type of radio signal takes up more “frequency” or space of the spectrum. Some FM signals are 15khz wide, others 10, some 7.5.

The old analog TV signals were 5 mhz wide.

Your radio is tuned to the center  frequency, then decodes what is received, however “wide” it is… AM, FM, FM music, data

If you tune your radio to 146.000 and listen to a transmitter doing 5khz deviation voice, FM, there is “stuff” at 145.995 and 146.005. using 10 khz of the “frequencies” or spectrum.

Two meters is 4 million hertz wide.  144.00 to 148.00 Mhz. How many 10khz wide voice signals will fit?

No radio is perfect. There is a need to leave some space between “channels” so a strong transmitter near you does not trash a weak signal on the next channel you want to hear.

So there is only so much room for a number of “channels” in any frequency range, depending on the type of signal. Go tune across the FM broadcast band. (75khz deviation)

Go read some basic stuff, then ask better questions, you will get better answers.




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