ACE GS PPT 15 may 2011

•To setup an autonomous Ground Station at ACE
• To retrieve TEC data operating on 437 MHz and 145
•To receive Satellite Beacon on 145 MHz using VHF
•To receive Satellite Telemetry data on 437Mhz using
OOK UHF receiver
•To log and analyze the data received
•Student Outreach Program
Our Ground-Station consists of 3 main parts:
1) Antenna Array
2) Rotor Mechanism
3) Processing Circuit
• Parameters obtained from
4nec2 software.
• Design was for 5 element 145
MHz Yagi-Uda antenna is
• 5 elements Yagi-Uda was
selected for:
1. Better directivity
2. Better sensitivity
3. Low Bandwidth
• Antenna parameters obtained from NEC aren’t
always practically realisable.
• Values had to be rounded up to achievable margin
and the resultant design was again simulated on the
• Best possible parameters were selected based upon
their practicality as well as fulfillment of specified
• Balun is also known as Quarter
Wave Transformer.
• It is used for impedance
• Length of balun is 1\4th of
• Practically, this value has to
divided by velocity factor of
the medium so as to account
for different velocity of signal
in different medium.
• Plane of polarization should be
maintained while folding dipoles.
• The distance between the folds of
the dipoles have to be maintained.
• For 437MHZ, a 7mm thick mild
steel former was used.
• For 145 MHz a 2 cm diameter
wrought iron former was used.
• Both these formers were
customized in the ACE workshop.
LMR 400
• Attenuation:
 5 dB/100m at 145 MHz
 8.9 dB/100m at 437 MHz
• Max Operating temperature:
85 ˚C
• Cost: INR 85/m
RG 214
• Attenuation
 8.57 dB/100m at 145 MHz
 15.95 dB/100m at 437 MHz
• Max Operating Temperature:
75 ˚C
• Cost: INR 500/m
 Dynamic Az/El tracking is a necessity
for precision in readings and to avoid
 Manual tracking is not practical given
the short Satellite pass duration ,
strength of signal being received &
weight of antenna setup.
 Though designing a rotor system is an
option but you will need to take care of 4-Crossed Yagi-Uda Rotator
many factors
 Water Proofing Motor framing  Options Available
 Wiring & Insulation
 Yaesu G5500
 Wind load Considerations
 Hygain
 Most importantly
 Kenpro
•Rotation Range:
Elevation: 180°0
Azimuth: 450°
•Maximum Vertical Load
:Elevation: 30 kg or less
Azimuth:. (200 kg) or less
•Rotation Time (Non Loaded)
:Elevation (180°): 67 sec at 60 Hz
Azimuth (360°): 58 sec at 60 Hz
•Comes with a controller which helps in interfacing with a
PC based tracking software
•Provides efficient control in both Azimuth and Elevation
•Compatible with most of the Antenna rotators available
•This controller board takes care of all the Talking !
(Interfacing )between the PC –Software
(Orbitron/Satscape ) and Antenna rotator(Yaesu G5500)
5 relays (Azimuth and Elevation Control)
AUX, Brake or Speed control.
RCI-SE Controller
•5 Relays
•2 x 8 Bit ADCs
•LPT Interface Port
Sensitivity upto -125 dBm
Inbuilt LNA & BFO.
Field Programmable VFO to
offset satellite Doppler shift.
Rugged and Robust.
Powered by Li-ion battery.
Plug and play device.
Requires operating license
ADF 7020
Sensitivity upto -118 dBm
No inbuilt LNA or BFO
VFO is not Field Programmable.
Delicate , requires ESD
Powered by power supply.
External peripheral components
No license required.
ADF 7020
Frequency 50- 3000Mhz
Noise figure; 1.1dB
Gain 20.5 dB
i/p VSWR 2:1
o/p VSWR 1.6:1
DC Supply Voltage 5V
Supply Current 70mA
Operating Temperature -40’C to 85’C
• Polarization Measurement Kit
(Phase and Gain Detector)
• 2 Inputs from 1 Crossed Yagi
• 2 Outputs to be given to
It is industrial grade Trans- receiver IC.
It is operational over a frequency band of
405MHz to 470 MHz and is tunable.
It’s power requirements are low (-118dbm)
Signal received at Ground-station would be
It supports packet data transmission.
Maximum bit rate is 156.2 kbps which is
much higher than our requirements.
• Inbuilt WISP – DDE protocol to
interface with compatible rotor
system. (Yeasu G-5500)
• Real time Tracking .
• Built in Voice Alerts.
• Wide range of satellites which can be
• 3-D Graphic User Interface
• It’s a FREEWARE !
• Crossed Yagi antenna successfully designed,
fabricated & characterized.
• Power link budget implemented.
• CC 1020 and AD 8302 ordered and procured.
• Ground-Station Control Room set up.
• Softwares like 4NEC2, Solid Works, Satscape,
Smart RF Studio were studied and used.
• AX.25 protocol studied using Slow Scan TV on commercial UHF Band .
• Morse Code transmission/reception.
• Radio Telescope was setup to monitor solar radiations.
• Tracked ISS.
• Radio propagation conditions were studied at the control room by setting
up VHF/UHF monitoring station.
• Blog and Facebook profile was created to reach out
to the students & interested people.
• Blog:
• Facebook Profile Handle:
Ace Satellite Ground-Station
• Student Interactive Session was conducted.
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