Thesis (MScEng)--University of Stellenbosch, 2001. / 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.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52100 |
| Date | 12 1900 |
| Creators | Nel, Francois |
| Contributors | Milne, G. W., Stellenbosch University. Faculty of Engineering Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 139 leaves : ill. |
| Rights | Stellenbosch University |
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