The standard antenna connector is a 50 ohm BNC. If the K2 has the built-in ATU, then the standard BNC socket is capped and there are an additional 2 BNC sockets from the ATU, selectable ANT1 and ANT2 from the front panel.
Built this in 1999 and it is still one of the best receivers I have used in 50+ yrs of being on the air. This rig was built for QRP contesting and won for my section. Also used it to make WAS QRP CW with just a simple 450 ohm fed inverted V.
Besides all of the performance features, it is a rig you can modify and fix or repair without 1000's of dollars of test gear.
Options added were the noise blanker, SSB, 160 M 2nd receiver, antenna tuner, audio filter and battery. If you add the 100 watt PA and high power tuner you can easily work DX and hold your own in contests.
Estimating the value of a rig can be challenging. We collect prices paid by real hams over the years to help you estimate the value of new a used Elecraft K2. Just bought or sold this model? Let us know what you traded it for and help other ham operators!
Based on historic data, today's second-hand price of the Elecraft K2 is around: