If I purchase a FT-817 from someone during the warranty period, the rig is still covered by the Yaesu warranty isn it?
NO. The warranty policy Yaesu has regarding previously-owned equipment is tough. The warranty applies ONLY to the original purchaser. If you buy a rig still in the unopened box from someone that recently bought it, you will have no warranty. The warranty card is not the “proof,” it is the bill of sale from an authorized Yaesu Dealer. The name and address need to match that of the person sending in the equipment or be able to explain you moved at least. Of course, you may recognize a way to handle this difficulty, but that can have problems too. You should consider that even “fresh” Yaesu gear being sold by a purchaser rather than a store should have less value simply because the warranty is gone!