Which tool, Wireshark or NetWitness, provides information about the wireless antenna strength during a captured transmission?

Wireshark.

Explanation:

Wireshark is a free and open source network packet sniffing tool, used for analysing, troubleshooting, software and communication protocol development etc.

It uses various extensions to capture wireless and cabled connections like AirPcap (air packet capture), pcapng (packet capture next generation.

It uses the device's antenna to capture wireless communication and gives the signal strength, noise ratio and other information of the antenna.