 The majority of glowbug transmitters are designed to be used in the CW radiotelegraphy mode.Glowbug transmitters having simple, tube-based designs were part of many beginner ham stations.According to author Richard H. Arland, interest in glowbugs has increased among QRP enthusiasts and others with a penchant for constructing their own equipment, and many hams are assembling simple HF CW transmitters.