Model Forum / Radio Controlled / Air Models / May 2004

It's hard to say.  They might be the same, or they might not.  It
depends on how the receiver is built.

Most JR receivers are single conversion, where most of the FMA ones
are dual conversion.  That alone will almost certainly mean that the
crystals will have different values.

For the most part, the crystals are identical except for the value --
but the values for different brands (or even models) can be quite
different, even though they're meant to receive the same channel.

Better just get a FMA crystal.  Perhaps another crystal will work, but
even so, it's possible that it'll work but with issues -- it's not
worth the risk.

Things that CAN be different.

(i) Frequency. It can be single or dual, and cut for above, or below the
incoming differeing of course by teh IF used. So thats 4 potential basic
frequencies all marked 'channel X receiver'

(ii) Overtone. It might be cut to work at teh fundamental, 3rd or 5th
overtone. If cut for a different setup to what it finds, it may not
ocsilate, or weakley.

(iii) capacitative and other loading. Crystals are quite happy to
ocsillate some way off the 'marked' frequency if loaded with capacitors.
Its probavbly possiibe to 'pull' one at leats a channel off band....

Answer? They might be identical. They might not work at all. They might
be half a channel out.

Wanna risk it?