ping.exe
Ping with timestamp
ping.exe -t localhost|Foreach{"{0} - {1}" -f (Get-Date),$_} > ping.txt
Ping with timestamp (another version + appending the log file)
ping.exe -t 8.8.8.8 | ForEach {"{0} - {1}" -f (Get-Date), $_} >> ping.txt
ping.exe -t localhost|Foreach{"{0} - {1}" -f (Get-Date),$_} > ping.txt
ping.exe -t 8.8.8.8 | ForEach {"{0} - {1}" -f (Get-Date), $_} >> ping.txt