•To setup an autonomous Ground Station at ACE• To retrieve TEC data operating on 437 MHz and 145 MHz•To receive Satellite Beacon on 145 MHz using VHF receiver.•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 Array2) Rotor Mechanism3) Processing Circuit

DESIGN:• Parameters obtained

from 4nec2 software.• Design was for 5

element 145 MHz Yagi-Uda antenna is shown.

• 5 elements Yagi-Uda was selected for:

1. Better directivity2. Better sensitivity3. Low Bandwidth

FABRICATION: • 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 software.

• Best possible parameters were selected based upon their practicality as well as fulfillment of specified criterion.

• Balun is also known as Quarter Wave Transformer.

• It is used for impedance matching.

• Length of balun is 1\4th of wavelength.

• 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

4-Crossed Yagi-Uda Rotator Setup

Dynamic Az/El tracking is a necessity for precision in readings and to avoid errors.

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 many factors

Water Proofing Motor framing

Wiring & Insulation Wind load

Considerations Most importantly

ACCURACY!!

Options Available Yaesu G5500 Hygain Kenpro

Specifications•Rotation Range:

Elevation: 180°0Azimuth: 450°

•Maximum Vertical Load:Elevation: 30 kg or lessAzimuth:. (200 kg) or less

•Rotation Time (Non Loaded):Elevation (180°): 67 sec at 60 HzAzimuth (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 Planes•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)LeftRightUp DownAUX, Brake or Speed control.

Specifications:•5 Relays•2 x 8 Bit ADCs•LPT Interface Port

RCI-SE Controller

WOUXUN- KGUVD1P• 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

protection.• Powered by power supply.• External peripheral

components required.• No license required.

WOUXUN KG UVD-1P 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 µController

• 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 -110dbm.

• It supports packet data transmission.

• Maximum bit rate is 156.2 kbps which is much higher than our requirements.

SATSCAPE:• 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 tracked.• 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: http://acegroundstation.blogspot.com/• Facebook Profile Handle:Ace Satellite Ground-Station• Student Interactive Session was

conducted.