To comment on a couple of posts:
Squeaks; Although I drive B744's for a crust [loaf even?], during any year I fly a variety of a/c down to the lovely DH-82A [Ahhh! de Havilland!!] The same technique applies to all; simply change the numbers while squawking.
However, if you DO operate in an environment with Jurassic radar systems, the old technique may apply. I would respectfully suggest that most Western world systems now rely on computer processing of SSR data, and that my earlier comments are valid.
FBW; Please don't perpetrate the myth they've tried here in Aust that you MUST have Mode C [Altitude reporting] to be any use to TCAS. A basic transponder still alerts the crew to your position. It may not give height [naturally], but helps the eyeballs to scan in the right direction. If you have a transponder, turn it on to your country's basic VFR squawk [as a minimum] EVERY time you are airborne! Please!!
G'day