Start/End Pad in Noise Gate

[Trebor]

Alternatively, you could search on-line for free VST Noise Gates to find other options.

“JB Phatt Pro” is a free compressor/expander/gate plugin that works in Audacity on Windows …

IMO most of the old JB (Jeroen Breebaart) plugins are worth having …
https://web.archive.org/web/20130329211641/www.jeroenbreebaart.com/audio_vst_jb.htm