The channel 3 is CB, FRS, MURS channels. The ham side is 146.420.
Channel 3 project.
So the "common" hams frequencies for the most used bands are:
6meters: 52.525mhz FM is the national FM calling frequency. Secondary is 52.540
And for those with Single Sideband capability the calling frequency is 50.110 USB for DX and 50.125 for "local".
2 Meter FM calling is 146.520 and secondary is 147.420
2 Meter SSB is 144.200 USB
ON the 70cm Band (440mhz) Calling frequency is 446.000mhz
for SSB it is 432.100 USB.
ON 10 meters with General and above license FM calling is 29.600 FM
For Technician license holders 28.400USB is the unofficial calling frequency.
For GMRS the "Emergency Frequency" is CH#20 which is 462.675mhz with a 141.3pl.
Finally if you live near waterways/oceans the Marine Emergency VHF frequency is 156.800 which all vessels are required to monitor when their radio is not in use for other communications.
And if you have Aricraft capabilities the "emergency frequency" is 121.500mhz AM.
Hope this helps some.