Just about any radio system used for comms with the command station could be adapted to a two-way mission. Mass and power budget are the limiting factors in most cases.
Which nanosatellite did you help design?
73, Drew KO4MA AMSAT-NA VP Operations
From: Shashank Chintalagiri [email protected]
I'm curious, as someone who was involved in designing a nanosatellite. What sort of payloads would be of interest to the amateur community? When we started out, we did spend a fair bit of time looking for payload, but most things to do with transponders seemed to be somewhat unfeasible.