ideal dipole gain

If I have a GSM dipole with MS Tx band(880-915MHz) gain spec but without Rx band(925-960MHz) spec,
how to calculate Rx band gain?
Can I use network analyzer to measure the dipole's Tx and Rx band returnloss then calculate the dipole's Rx band gain according to the dipole's Tx band spec and the measured returnloss?

thanks a lot :)

Dipoles have the same gain .
Different frequency only get different dimensions, but not change it's gain.

Cheers

Return loss doesn’t tell you about antenna gain. The best measurement for gain is to do a comparison between your dipole and a reference dipole, using an anechoic chamber or an open site.
The thickness of the dipole elements gives you the bandwidth. Thicker it is, wider bandwidth you get.
rgds