[Origineelreclamebord]

I'm no expert on this, so someone please correct me if I'm wrong, but I think it is like this:

Low frequency: Longer range (waves carry further) but less data capacity (fewer 'waves' to carry information in);
High frequency: Shorter range, but more data capacity (more 'waves').

I guess it would also depend on how much energy you are using to send out your signal, but this is why a low frequency may be interesting for some applications (such as military) whereas your WiFi connection benefits from using a very high frequency, which is why many WiFi routers support 2.4Ghz and 5Ghz connection: One for an acceptable range, one for speed so long as you are nearby.

For your consideration of crystals vs. 2.4Ghz, I think you need to consider that most the 'old' crystal systems are on a fixed frequency and can be sensitive to interference from other radio signals that are being transmitted in the area. In contrast, 2.4Ghz systems are 'hopping' from one frequency to the next using an algorithm. During the binding process, you ensure that the receiver understands the frequency hopping algorithm of your transmitter. By hopping frequencies, the signal is generally insensitive to interference.