system could transmit within an area of approximately 700 square feet. The system consisted of a low-frequency FM radio transmitter and microphone, utilized five subminiature vacuum tubes, and was powered by two hearing aid batteries. The Vagabond system was expensive and somewhat fragile, but was adopted for use by several Las Vegas venues of the time. Not until 1990 did Shure re-enter the wireless microphone market with the introduction of the L Series. Even before Shure re-entered the wireless microphone market though, concert engineers commonly specified Shure microphone capsules for the wireless microphone systems they were using. Once Shure introduced its own UHF wireless microphone system, which featured wireless versions of several popular Shure microphones, they no longer made capsules available for other manufacturers' systems. This practice encouraged sales of Shure wireless systems and gained Shure market share in the category. Shure's UHF system featured software control and the ability to operate as many as 78 systems simultaneously. On the ULX series (introduced in 2002), they featured the ability to scan for clear wireless channels, sound quality rivaling wired models, a less expensive package, and the ability to operate 40 systems simultaneously. The ULX system was awarded a TEC Award in 2002. In 2005, Shure introduced the SLX series of wireless microphone systems. It featured their patented "audio reference companding", a level-dependent companding protocol that does not compand low-level audio where the wireless artifacts would be more audible. "Audio reference companding" was said to help a wireless system sound more like a wired microphone due to clearer sound, a lower noise floor, and greater dynamic range. In 2005, the SLX series was awarded a TEC Award. The following year, The UHF-R series was introduced with audio reference companding as a main feature and "wireless workbench" software for computer coordination and control of frequency selection, customized settings, and synchronization of multi-system components. The UHF-R series received a TEC award in 2006. In 2011, they introduced their first digital wireless system, the PGX digital series, augmenting the released previously entry-priced PGX series. The PGX digital wireless system transmits 24-bit/48 kHz digital audio and utilizes the 900 MHz frequency band, and is able to operate with up to five systems simultaneously. Like all Shure wireless, it is available with a variety of popular Shure microphone models, or in bodypack configurations for use with lavalier or headset microphones, or connected to an instrument cable.