This rocket stove is not only very simple to make it's very portable.
The only materials you will need are 2 soup cans, a paint can, some sand, pebbles and a stove grate.
An improvement on this design could be using a 5 gallon metal bucket instead of a 1 gallon paint can, which will make the entire unit burn hotter. This is because the vertical burn shaft should be 3 times taller than it's diameter.
So, a 3″ diameter tube should be at least 9″ tall, a 4″ tube should be 12″ tall. The closer you can get to this the better.
When it burns hotter there is less smoke because smoke itself is combustible. With less smoke your not giving your location away so easily.