Commercial TV and Radio transmitters
Commercial TV and Radio transmitters
(OP)
I was just curious. Does anyone know if commercial television and radio stations still use vacuum tubes in the final amplifier stages of the transmitter or are they now solid state?





RE: Commercial TV and Radio transmitters
RE: Commercial TV and Radio transmitters
Harris Communications is one of the major suppliers of commercial television site transmitter systems and produces both solid state and tube based transmitters as shown in the links below.
I've installed and maintain some equipment installed at a local television station.. Their analog TV transmitter is similar technology as the Harris DTV solid state below and their new digital HDTV transmitter is "tube", an IOT as discussed in the second link below..
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RE: Commercial TV and Radio transmitters
I'll parenthetically decode the acronyms for the non EE types who may lurk.
Harris and others do indeed make high power solid state transmitters, however the additional up front cost usually exceeds the savings (if any) of the solid state devices over the projected life of the transmitter.
High power UHF systems still means tubes. KUAT-DT uses E2V MSDC IOT s (Multi Source Depressed Collector Inductive Output Tubes. A type of klystron.) While the 60+ KW TPO (Transmitter Power Output) could be achieved with FETs (Field Effect Transistors), the efficiency is lower and the initial cost higher than the tubes.
We do have low power TV and DT transmitters which are all solid state. They have the advantage of being less time consuming to tune up when replacing active components, but they also do not appreciate the Summer temperatures which we have in Tucson and require an air conditioned building. The IOTs are liquid cooled and don’t mind the heat of the Sonoran Desert. Aside from being at 8,550-Ft in the Santa Catalina mountains 6,000-Ft above and 20º cooler than the city of Tucson.
I remain,
The Old Soldering Gunslinger