| Abbreviation | Definition |
|---|---|
| ISRA | Idaho Society of Radio Amateurs, Inc. |
| JARA | Jamaica Amateur Radio Association |
| JARC | Jackson Amateur Radio Club |
| JARC | Jefferson Amateur Radio Club |
| JARC | Juneau Amateur Radio Club |
| JCAR | Jackson County Amateur Radio |
| JOTA | Jamboree Of The Air |
| KARC | Kalamazoo Amateur Radio Club |
| KARO | Kane Amateur Radio Operators |
| KARS | Katy Amateur Radio Society |
| KAT | Klamath Amateur Television |
| KCSARC | Klamath County Schools Amateur Radio Club |
| KenleyHeavisideLayer | Inner space layer reflecting radio-frequency signals back to earth, causing 'skip': |
| KW | Kurz Welle (Short Wave) |
| LARA | Lockport Amateur Radio Association |
| LARC | Lincoln Amateur Radio Club |
| LCARC | Las Cumbres Amateur Radio Club |
| LCARC | Louisiana Council of Amateur Radio Clubs |
| LCARC | Loyalist City Amateur Radio Club (Canada) |
| LHCP | Left-Hand Circularly-Polarized |