| Abbreviation | Definition |
|---|---|
| CCRA | Contra Costa Repeater Association |
| CDMA | Code Division Multiple Access |
| CDR | Controlled Directional Reception |
| CFA | Cross Field Antenna |
| CFARS | Cape Fear Amateur Radio Society |
| CFR-47 | Code of Federal Regulations Title 47 (FCC) |
| CGR | Centre de Gestion des Radiocommunications |
| CGRS | Coast Guard Radio Station |
| CHA | Cliff Hanger Antenna |
| CIO | Carrier Insertion Oscillator |
| CLMR | Civil Land Mobile Radio |
| CMM | Coordinate Measuring Machine |
| CMRR | Common Mode Rejection Ratio |
| COAX | CO-AXial (cable) |
| COAX | Coaxial Cable |
| CO-AX | Abbrev/Coaxial Cable or other references to Co-Ax |
| COFT | Calculated Optimum Fixed Tuning |
| CORA | Central Oklahoma Radio Amateurs |
| CP | Circular Polarized |
| CPC | Constant Power Crossover |