15m

At the moment 15m is a very useful band. It stays open longer than 10m and with the high sunspot count, it is capable of worldwide DX.  Although many people have migrated to FT8 to chase DX, some may still go on CW.

Back in the mid 1970s I designed the QRP Pipit CW transceiver. For many months it was the only rig used. It worked really well with just a low dipole.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/15m-qrp-cw-pipit.