I have been able to operate throughout Australia without a transponder but Singapore Airspace is a little different to our open spaces.
As a result, I'm in the midst of having a transponder fitted.
We chose Microair avionics, an Australian made product with a great reputation.
I'll give you some more details as we go but in short, I need a compact, light weight unit that I could rely on!
Check them out at:
Best of all - Microair has a 15% off sale running at the moment!! Handy for Christmas presents ...