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== Large Dish / C-band ==== Large Prime Focus Dish =='''LNB''' - The LNB (Low Noise Block Downconverter)converts the signal from the satellite into a signal for the receiver. Some feedhorns come with LNBs.'''LNA''' - The low noise amplifier (LNA) is a special type of amplifier used in older satellite systems amplify and receive weak satellite transmissions from space. Early communications satellites transmitted at a lower power. Early Satellite systems used the a LNA or Low Noise Amplifier and no conversion was done in the LNA. '''LNB''' - The LNB (Low Noise Block Downconverter)converts the signal from the satellite into a signal for the receiver. Some feedhorns come with LNBs. The functions of the LNB were at one time provided by two separate components, a Low Noise Amplifier (LNA) for signal amplification and a block down converter for down conversion. '''LO''' - The LO (Local Oscillator) is the frequency of the LNB itself. So you have the received Satellite signal frequency which is one value, and the LO which is another value. When the LNB convers the Satellte signal to one digestable by the receiver, the frequency adjustment is made by subtracting the LO frequency from the satellite frequency. There are different LOs providing different frequency ranges. == LNB Types ==LNB stands for Low Noise Block downconverter. C Band LNB's are measured in degrees Kelvin, with a lower number representing a higher grade LNB. Ku band LNB's are measured in decibels, with a lower number also representing a higher quality LNB.{||-|[[Image:littlelnbexamplediagramdeal.png]]|[[Image:littlelnbexamplediagramdeal2.png]]|}* '''Standard LNB''' - 10 GHz LO, works for one band only. Normally has a feed horn assembly built onto the LNB. This LNBs polarization switching is done by a DC voltage on the coax - 12.5 to 14.5 volts gives vertical and 15.5 to 18 volts gives horizontal. * '''Universal LNB''' - works in two bands, 10.8 to 11.8 GHz and 11.6 to 12.7 GHz while having LOs of 9.75 and 10.60 GHz. Band switching is done via a 22 KHz tone sent from the satellite receiver. With the tone on the LO is 10.6 GHz, otherwise it is 9.75 GHz. Polarization is controlled the same as in the "STANDARD" LNB. A tone is sent to the Universal LNB at 22 KHz to tell it to switch from one band to another, such as from high to low, or low to high. Modern satellite receivers have the 22 KHz functionality built in.* '''Enhanced LNB''' - works from 10.7 to 11.7 GHz and has a 9.75 GHz LO. These were designed for the Astra satellites and have a built in feed assembly. Polarization is controlled the same as the "STANDARD" LNB.When looking for a feedhorn / LNB combo, remember 4DTV compatibility is recommended since nearly all C-band programming has moved to digital, and 4DTV is digital C-band.* C/Ku/DBS Feedhorn: [[Image:ckudbsfeedhornpic.jpg]] == Miscellaneous Illustrations =={||-|* Feed horn Cover[[Image:bigdishfeedhorncap.png]]|* Chaparral Feedhorn Cap[[Image:feed_horn_cap.gif]]|* Servo Motor[[Image:servomotorExample.jpg]]|}