Ive heard talk about low-level and high level combining. Whats the difference?
In low level combining the HD signal is combined with the analog signal at the output of your transmitter’s exciter and then fed to a common amplifier for transmission. There is no need for additional equipment. Although, several transmitter manufacturers have units that can achieve 20+ kW analog and HD digital in the same transmitter, and there are exceptions for custom designs, in general, low-level combined transmitters usually have an output power that does not exceed 7.5 kW. If your station requires more output power than 7.5 kW, most commonly you will have to employ a high-level combining technique. Using this technique, the R.F. from the analog transmitter and from the digital transmitter is combined in a “combiner”. Standard high-level combining is a lossy procedure and a considerable amount of heat is produced requiring the need for additional air-conditioning. One procedure for combining is called the mid-level or split-level technique. This technique is more efficient than s
