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Frequency application – first draft
AMSAT-OZ
C/O Ib Christoffersen
Technical University of Denmark, November 23rd 2001
Dear Sirs,
We hereby apply for a frequency in the 70-centimeter radio amateur satellite band for
a new satellite, DTUsat. DTUsat is a CubeSat1 built by engineering students at the
Technical University of Denmark as an educational project. We are currently a team
of 40 persons working on the satellite, which we hope to launch in the spring of 2003.
However, a satellite without communication might as well be made of concrete. We
are currently designing a half-duplex transceiver for the satellite, but for this to be
really useful, we will need a frequency, too.
Our reason for applying for a radio amateur frequency is threefold.
 As we are students and on a budget, the availability and pricing of radio amateur
equipment is a big advantage.
 As the satellite is a small project without high-profile payloads, the difficulty of
international frequency coordination would make it next to impossible to get a
global frequency assigned.
 As this satellite is the first we build, we would appreciate amateur assistance in
acquisition, tracking, and telemetry recovery.
We realize that the frequency bands that AMSAT holds are valuable assets.
 Our satellite uses half-duplex communication, meaning that a single 9k6 FSK
frequency slot in the 70-cm band is enough.
 Our satellite is designed to commit suicide by dropping itself into the atmosphere
in about 2 years. This is accomplished by means of an electrodynamic tether,
which will be the first of its kind.
 Our satellite will incorporate a further suicide command, which will stop the
transceiver if need should arise.
 Our satellite will provide the radio amateur satellite community with some
service, when it is not communicating with the command station.
As the satellite is very small – only 1 kg and a volume of 10 centimeters cubed – the
power and space available is very limited. It is thus not feasible to fly a linear
transponder. We instead propose to fly a test transmitter that will broadcast a CW
callsign and AX.25 packets containing telemetry in 9k6 FSK format worldwide. Our
idea is to repeat the telemetry packets, but step down the radiated power from 500
mW to almost nothing to facilitate test of ground equipment sensitivity. This suite of
1
The Cubesat concept was proposed by Prof. Robert J. Twiggs of Stanford University in 1998. Details
are found at http://ssdl.stanford.edu/cubesat/
packages will be repeated about once a minute, starting with full power and stepping
down. Each packet will contain telemetry on the power level used.
The satellite will be equipped with three additional payloads. A camera for ground
and launch photography, an electromagnetic active attitude control system, and an
electrodynamic tether that will be used for changing the orbit. More details on these
payloads are available at the DTUsat homepage, http://www.dtusat.dtu.dk.
As the power is very limited, we will have to ask the community not to operate the
satellite. This unfortunately limits the usefulness of the payload data downlink to the
satellite amateurs situated in Northern Europe, who might be listening when we
operate the satellite from Denmark. The payload data will be made publicly available
via the Internet. The test transmitter will be available worldwide.
Best regards,
Anders Nielsen
Heine Bodekær
Niels Holmgård Andersen
DTUsat/radiohardware
Contact information:
DTUsat/radiohardware
C/o Olav Breinbjerg
Department of Electromagnetics
Oersteds Plads, build. 348
Technical University of Denmark
DK-2800 Lyngby
DENMARK-EUROPE
Web: http://www.dtusat.dtu.dk
Email: [email protected]
Ideas:
435.200 MHz – bandwidth 25 kHz, not including doppler shift.
435.275 MHz
436.325-436.475 MHz
436.675 MHz
437.000 MHz