Yeah, you can. Just needs some experimenting. If you have an antenna analyzer it would help a lot. You do know the formula for finding the antenna length right? For receive, it isn't all that critical for length, but for transmitting you need to be within the tolerance for the frequencies you plan to use.
If you need help, just come back here and post your questions.
Just in case you need the formula:
Full wave length = 936/Mhz
5/8 wave length = 585/Mhz
1/2 wave length = 468/Mhz
1/4 wave length = 234/Mhz