General questions about TX and RX, and changing crystal (frequency)

[MakeHobbyRC]

Hi, I need some help please in understanding a bit more generally about transmitters and receivers..
1) Does the frequency (of Tx and RX) have to be EXACTELY the same to match and work together? (I have a 35.180MHz TX and a receiver stated as a 35MHz...it works... )
2) Can I put ANY type of crystal in my TX ESky 4CH X'TAL 35.180MHz (TX 35MHz)... to have the use of that radio controller over other frequency bands??? (or not...)
What are the technical characteristics I need to look for to find COMPATIBLE crystals with my TX)
I thank you for your times guys,
Best,

[Schmitty1944]

I'm in no way an expert on this but since no one has answered and I have quite a lot of experience with switching crystals and miss-matched transmitters and receivers I'll give you my thoughts.
It's a confusing mess as to exactly which crystals work with any given radio brand and type.

1) Yes. they have to be exactly the same frequency. The crystal you have simply labeled 35mhz must be 35.180mhz and just not labeled specifically enough.

2) Yes. It should work with any frequency crystal within the 35mhz band as long as it is the correct brand and type to work with that particular transmitter.

There are different crystals for AM and FM, There are single conversion and dual conversion (crystals are different). The crystals for TX and RX are different. Some brands are compatible and some are not. It's best to stick with the correct branded crystals for your transmitter and receiver but if you've got access to other parts to experiment there are odd combinations that work. For example I just tried a Futaba receiver with an Ace transmitter and it works great. Always perform a thorough range test before committing to a model you are going to set loose in the wild.

Jason