Something that many people seem to forget (or never knew) is that currently Futaba is the only manufacturer which splits the 72Mhz band into a high and low band. With modern non-Futaba equipment (less than 10 years old) you don't have to worry about the high/low band issue.
Using a Futaba low-band receiver with a high-band crystal will normally result in reduced range. This is Futaba's recommended method of identifying if your receiver is high-band or low-band.
How can I tell if my receiver is high band or low band?
The receiver should have a sticker on it indicating High or Low. If it does not, the best way is to have a service facility check what frequency it is tuned. A "quick check" in the field would be to test it with a transmitter tuned to a channel in the teens and a transmitter tuned in the 50s. There will be a dramatic difference in range shown, with the better range being the side to which the receiver is tuned.
www.futabarc.com/faq/service-faq.html#q637