Adaptive coding techniques for time varying channels such as the HF (2-30) MHz have been under investigation for several decades [Honary 1981, Katakol 1987, Zolghadr 1989, Bate 1992, etc.]. Forward error correction applied to these channels are designed to give the desired performance for the worst channel state. Hence when the channel is relatively error free unnecessary error correction power and redundancy is being employed. This naturally reduces the overall information rate. In order to transmit data efficiently in a time varying channel an ideal error control scheme should achieve a lower average output bit error rate than that obtainable with a fixed rate system. This is done by matching the code to the changing channel conditions. In this report a number of embedded coding techniques employing block codes for time varying channels have been proposed and investigated. A novel statistical channel evaluation technique based on trellis of block codes has also been devised. The HF(high frequency) link has been established with a receiver station Mauritius and measurement of data from UK has shown that it is working as expected.