I didn't mean to turn this into an antenna debate, The other ways you point out SHOULD be obvious when inspecting the antenna. Also, I did say ASSUMING the RX doesn't have any internal loading, the high dollar ones you point out MUST have something either obvious when you look at the antenna or internal. However, I will capitulate and agree that it is Brand / Model dependent since there are apparently some makes that DO have said loading.

However, this whole line of discussion is a moot point since as you all point out, if it hit hard enough to sever the antenna the RX should be checked out anyhow. The added cost of antenna replacement cant be much if you already need to send it in so why not just do it?

PS: Nice link to the Antenna page...