You might understand this differently to me, but I notice that in the beginning of Revelation 11 that the temple is not yet destroyed.
Revelation11:1 And there was given me a reed like unto a rod: and the angel stood, saying, Rise, and measure the temple of God, and the altar, and them that worship therein.
2 But the court which is without the temple leave out, and measure it not; for it is given unto the Gentiles: and the holy city shall they tread under foot forty and two months.
Forty and two months is 3.5 years.
Jerusalem is also identified in this chapter in v.8.