awareness beware blue camera camera-surveillance cctv closed-circuit-tv communicating communication external information informing light lighting lookout monitoring observation observe public safety security security-camera surveillance surveillance-camera under-observation video-camera watch watched community accomodation apartment apartments balcony cold contrast convert converted copyspace dish dundee flat flats hill home house jute mill mills New old roof satellite sky slope snow steep stone stonework together turret turrets tv wins winter Alster antenna boat broadcast cell cellular city clouds electromagnetism germany hamburg lake landmark mast mobile radio radio-mast receiver reflection scene Signals tele michel telecommunications Telemichel telephone television television station television tower tower transmitter advice alert announcement black cameras center centre extensive monitors notice notification sign signage thorough video warning warning-sign white acoustics amplifier audio audition broadcasting commentator concept device electronic entertainment equipment increase instrument interview journalism live media micro microphone music old style professional Recording reinforce sound Speaker speech station stereo studio technology transmitting voice volume 24/7 cage day-&-night digital digital-camera enclosures exterior