WaVue-4 is a state-of-the-art, cost-effective, compact spectrum analyser engineered for field use. It addresses the need for portable spectrum analysers combining durability with convenience. Durability means maximum RF protection and ruggedised construction, while convenience involves ease of use, intuitive interface, flexible test accessibility and compactness. It maintains comparable performance and accuracy to conventional spectrum analysers while serving laboratory applications. Employing state-of-the-art reception techniques with Zero-IF and FFT combined, WaVue-4 provides required accuracy and speed. The frequency range covers 400-4000 MHz including 2G GSM, 3G UMTS, 4G LTE, and WiFi 2.4 GHz. Its compact size enables testing scenarios difficult to realise before, especially in-building sites like DAS and small cells.