An economical do - it - yourself ground station for school pupils

Nel, Francois (2001-12)

Thesis (MScEng)--University of Stellenbosch, 2001.

Thesis

ENGLISH ABSTRACT: The aim of the thesis is the design of an economical do - it - yourself ground station for school pupils to communicate with SUNSAT 1. The ground station should also be more economical than a hand - held transceiver radio. The do - it - yourself requirement is there to arouse an interest in electronics, radio frequency electronics and satellite communications in school pupils. A system-level design was done for a ground station consisting of modules which may be bought individually as do - it - yourself kits to eventually produce a full set. The modules are a VHF receiver, a VHF transmitter, a UHF down converter and a modem. Each module has functions which aid in the process of communications (data as well as voice) between the satellite and the ground station. A VHF receiver was designed and implemented to be capable of receiving RF signals from SUNSAT 1. A crystal controlled oscillator was designed that oscillates with a frequency tolerance of less than or equal to ± 0.003 % when aligned without the necessary IlF equipment. An economical Broadband Signal Generator was implemented with a 74ACT14 logic IC, which may be used to align the receiver. The higher harmonics of a square wave with a fundamental frequency of 4 kHz are used as a RF source. A sound card was utilised as a modem to receive 1200 baud AFSK (AX.25 protocol) data and the software was also used to display the data on PC. The data was transmitted from another ground station

AFRIKAANSE OPSOMMING: Die doel van die tesis is die ontwerp van 'n ekonomiese doen - dit - self - grondstasie vir skoolkinders om met SUNSAT I te kan komunikeer. Die grondstasie moet ook meer ekonomies wees as 'n handstelradio. Die doel van die doen - dit - self - beginsel is om die belangstelling in elektronika, RF elektronika and satelliete by skoolkinders aan te moedig. 'n Stelsel ontwerp van 'n grondstasie is gedoen wat bestaan uit modules wat afsonderlik as doen - dit - self - modules aangeskaf kan word om so tot 'n totale grondstasie op te bou. Die modules is die "VHF" - ontvanger, "VHF" - sender, UHF - afmenger en 'n modem. Elke module verskaf funksies wat bydra om met SUNSAT I te kan kornmunikeer. 'n VHF - ontvanger wat in staat is om RF - seine vanaf SUNSAT I te ontvang is ontwerp en gebou. 'n Kristal b heerde ossillator is ontwerp met 'n frekwensie toleransie van kleiner en gelyk aan ± 0.003 % wanneer dit ingestem word sender die nodige RF toerusting. 'n Ekonomiese wyeband - seingenerator is gemplementeer met 'n 74ACT14 logiese vlokkie om as 'n RF - bron gebruik te word om die ontvanger in te stel. Die boonste (hoer) harmoniek van die 4 kHz vierkantsgolf word as 'n "RF bron" gebruik. 'n Klankkaart is suksesvol gebruik as 'n modem om 1200 baud AFSK data (AX.25 protokol) te ontvang en die data met die nodige sagteware op 'n skerm te vertoon. Data is uitgcstuur vanaf 'n ander grondstasie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/52100
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