What is the difference between the NCDXF beacon system and other modern systems such as RBN and WSPR?

The NCDXF beacon system transmits fixed signals that radio amateurs receive to assess propagation conditions. In contrast, the Reverse Beacon Network (RBN) and the Weak Signal Propagation Reporter (WSPR) work on the opposite principle. With RBN and WSPR, radio amateurs themselves send out test signals which are received by automatic receivers (spotters) and the data is made available via the Internet. These systems are particularly useful for experiments and antenna comparisons, but do not provide the same quick overview of the upper shortwave bands as the NCDXF beacon system.