Test loop translator: Difference between revisions

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[[File:TLT.jpg|thumb|upright=1.8|Tampa Microwave Lab, Inc. LTT-03-1RU-107 Test Loop Translator]]

A '''test loop translator''' ('''TLT''') is a type of [[radio frequency]] converter or [[heterodyne]], used to translate between [[Telecommunications link|uplink and downlink]] segments (generally in the same band), to allow for "loop-back" testing and calibration of a satellite [[ground station]] without the need to interface with the [[satellite]].<ref name=novella>{{cite web|title=Test Loop Translator|website=http://www.novella.co.uk/test_loop_tech.htm|publisher=Novella Satcoms Ltd.|accessdate=23 February 2015}}</ref><ref name=atlantic>{{cite web|title=Model ASC 710C Test Loop Translator|url=http://atlanticsat.com/ASC710C.htm|publisher=Atlantic Satellite Corporation|accessdate=23 February 2015}}</ref>

The test loop translator is an extremely valuable tool for evaluating the performance of satellite earth stations. It allows the user to carry out analysis, alignment and [[system testing]] without incurring satellite airtime costs and the risk of interfering with other satellite users. Thus, it has applications during equipment development, qualification, trouble-shooting[[troubleshooting]] and in-service routine monitoring.<ref name="Loop Test Translators for Satcom Systems">{{cite web|title=Loop Test Translators for Satcom Systems|url=http://www.atlantecrf.com/pdf_downloads/MJ%20Article%20-%20Loop%20Test%20Translators.pdf|website=www.atlantecrf.com|publisher=AtlanTecRF}}</ref>

TLTs generally contain a fixed or preset [[local oscillator]] (LO) and a preset [[Gain (electronics)|gain]], though the LO and gain may be adjustable in some models.<ref name=novella/> Most models have a negative gain (i.e., a loss), with -15 [[decibel|dB]] being the most common.<ref name=novella/> Test loop translators can cover one or more of the satellite communication bands S, C, X, Ku, DBS and Ka.<ref name="S C X Ku DBS bands">{{cite web|title=Loop Test Translators|url=http://www.atlantecrf.com/products/satellite_communications_equipment/loop_test_translators/s_c_x_ku_dbs_bands.htm|website=www.atlantecrf.com|publisher=AtlanTecRF}}</ref> <ref name="Ka Bands">{{cite web|title=Ka Band - Loop Test Translators|url=http://www.atlantecrf.com/products/satellite_communications_equipment/loop_test_translators/ka_bands.htm|website=www.atlantecrf.com|publisher=AtlanTecRF}}</ref>

Test loop translators can cover one or more of the satellite communication bands S, C, X, Ku, DBS and Ka.<ref name="S C X Ku DBS bands">{{cite web|title=Loop Test Translators|url=http://www.atlantecrf.com/products/satellite_communications_equipment/loop_test_translators/s_c_x_ku_dbs_bands.htm|website=www.atlantecrf.com|publisher=AtlanTecRF}}</ref> <ref name="Ka Bands">{{cite web|title=Ka Band - Loop Test Translators|url=http://www.atlantecrf.com/products/satellite_communications_equipment/loop_test_translators/ka_bands.htm|website=www.atlantecrf.com|publisher=AtlanTecRF}}</ref>

==References==