[chirp_users] # of Channels

Ray Hutchinson rdhutch at pacbell.net
Sun Sep 2 14:28:29 PDT 2018

As others have noted, the number of 2 meter frequencies (channels) depends significantly where you are located in the US.  Some areas use 20 kHz channel spacing, while here in Southern California, because of the large numbers of licensed hams, and high demand for frequencies, the local area 2M frequency coordinating body (TASMA) has opted to publish a frequency coordination band plan with 15 kHz channel spacing.   It is strongly recommended, and "good amateur practice" says that one adhere to these coordinated frequency band plans as much as possible.
TASMA officially lists 87 Repeater frequency pairs, and 46 recognized simplex channels, and a handful of special use channels in the So. CA 2M band plan.  In the event of  interference complaints, the FCC will generally respect the local coordinating body's band plan and resolve the issue in conformance with that plan.  Again, adhering to local band plans is considered "good amateur practice" a FCC requirement of all hams.
You should find the website for your geographical area's local Frequency Coordinator and check to see if they have specific frequencies or channel band plan published as recommended frequencies.  While one can legally deviate from the band plan, so long as they don't cause interference to users conforming to the band plan, still following the band plans where they exist is again, required "good amateur practice".
HTH and 73 de Ray, AE6H

    On Sunday, September 2, 2018 1:34 PM, r norris via chirp_users <chirp_users at intrepid.danplanet.com> wrote:


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 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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