Chad - having no aerial with the TX turned on is just as bad (if not worse) than not having it extended.

Removal of the crystal prevents the oscialltor from functioning thus the TX final amp has nothing to amplify and no damage will be done. For those who are interested the damage is caused since the final amp expects to see a certain impedence to minimise losses. The aerial only presents this load when it is fully exteneded. If it is not then it will cause an impedence mismatch which inturn causes reflections back down the aerial and into the final output transistor. Since the transistor is not designed to have power coming back at it, it will dissipate this energy as heat. After a while the transistor will heat up too much and fail. For the power outputs that we use this will take a while, where I work we deal with high power radio gear (50W) and have transmitters that will fail within microseconds if the antenna load is removed.

Hope all that makes sense

Cheers
Vaughan