I broadcast from a local radio station and the transmitter is very close to the mic. It causes a lot of noise and can be heard in the recording. Can I remove the background noise? 
Can I remove the background noise?
Let’s start with no.
Assuming an AM station, the interference is generally moving and constantly changing with the broadcast show. That immediately takes you straight out of most Audacity tools and filters which depend on one, single, constant noise to work.
Congratulations. This is one of the top tricky engineering problems of all time. A studio at the transmitter. Solving it is not fun, but you need to do it at the performance/recording step, not post production.
So what’s the station, what’s the frequency, what’s your microphone and how are you recording your show?
Koz