Having a filter is preferable, but if filter is very costly, you may servive even without it.
Also try following scan which shows intensity of interfering RF noise also:
Spektrum - How-to Speedily Scan RF Noise in band 24MHz ~ 1800MHz
Having a filter is preferable, but if filter is very costly, you may servive even without it.
Also try following scan which shows intensity of interfering RF noise also: