The large size of dish required for lower frequencies led to the dishes being constructed from metal mesh on a metal framework. With lower frequencies, C-band for example, dish designers have a wider choice of materials. A typical value for a consumer type 60 cm satellite dish at 11.75 GHz is 37.50 dB. The actual gain depends on many factors including surface finish, accuracy of shape, feedhorn matching. The theoretical gain ( directive gain) of a dish increases as the frequency increases. A new form of omnidirectional satellite antenna, which does not use a directed parabolic dish and can be used on a mobile platform such as a vehicle was announced by the University of Waterloo in 2004. Direct broadcast satellite dishes use an LNBF, which integrates the feedhorn with the LNB. The LNB converts the signals from electromagnetic or radio waves to electrical signals and shifts the signals from the downlinked C-band and/or K u-band to the L-band range. This feedhorn is essentially the front-end of a waveguide that gathers the signals at or near the focal point and 'conducts' them to a low-noise block downconverter or LNB. Mounted on brackets at the dish's focal point is a device called a feedhorn. The parabolic shape of a dish reflects the signal to the dish’s focal point. Schematics of reflection principles used in parabolic antennas.