Hardware

This section describes the hardware side of the UFSC ground station and details the main peripherals that will be used in this project. Most of the components described here are represented in the block diagram.

Antennas

There are two antennas in the ground station: One for VHF and one for the UHF band. The main characteristics of these antennas can be seen in Table 2.

Table 2 Main characteristics of the ground segment antennas.
Characteristic	VHF Antenna	UHF Antenna	S-Band Antenna
Brand	M²	Cushcraft	TBD
Model	2MCP14	A719B	TBD
Type	Yagi	Yagi	TBD
Number of elements	14	19	TBD
Frequency range	143-148 MHz	430-450 MHz	TBD
Gain	12.34 dBi	15.5 dBi	TBD
Power rating	1500 W	2000 W	TBD
Boom length	3.2 m	4.1 m	TBD
Longest element	1.02 m	0.34 m	TBD
Weight	2.72 kg	2.55 kg	TBD

More information about the VHF and UHF antennas can be found in [M2 Antenna Systems, Inc.21] and [Cushcraft Corp.] respectively.

Surge Protector

To protect the ground station electronics of possible atmospheric discharges in the outside components, two surge protectors will be used (one for each antenna). The gas surge protectors safely discharge/deflect up to 5000 A of peak current to earth without causing damage to an independent ground. This kind of device is installed near the antennas, in cascade with the RF cables.

For this project the model MFJ-270N will be used, and a picture of it can be seen in Fig. 2.

Rotator

All antennas track the satellite through a two-axis rotator (azimuth and elevation). The used model is the Hy-Gain RAS-2, which is a heavy-duty antenna rotator designed for medium to large HF and VHF/UHF antennas. It features a robust construction with a 1,000 lb (454 kg) thrust bearing and 200 lb (91 kg) continuous wind load rating, making it suitable for demanding installations. The rotator uses a dual-drum cable system for precise 360-degree rotation and includes automatic braking to prevent unwanted movement.

A picture of this rotator can be seen in Fig. 3, and the main characteristics can be found in Table 3.

_images/ras-2.jpg — Fig. 3 Hy-Gain RAS-2 rotator and controller.

Table 3 Main characteristics of antennas’ rotators.
Characteristic	Value
Brand	Hy-Gain
Model	RAS-2
Voltage requirement	12-24 V_DC
Current consumption	3-5 A
Motor voltage	13.8-24 V_DC
Rotation time (elevation, 180^°)	80 sec (12 V), 40 sec (24 V)
Rotation time (azimuth, 360^°)	120 sec (12 V), 60 sec (24 V)
Rotation torque (elevation)	58 kg·m
Rotation torque (azimuth)	58 kg·m
Braking torque (elevation and azimuth)	276 kg·m
Vertical load	318 kg
Pointing accuracy	1 degree
Wind surface area	2.8 m²
Weight	20 kg

More information about the ground station rotator can be found in [MFJ Enterprises Inc.25].

Amplifiers

Power Amplifiers (VHF/UHF)

A picture of the power amplifier can be seen in Fig. 4, and the main characteristics are available in Table 4.

_images/zhl-50w.png — Fig. 4 Mini-Circuits ZHL-50W-52-S+ power amplifier.

Table 4 Main characteristics of the ZHL-50W-52-S+ power amplifier.
Characteristic	Value
Brand	Mini-Circuits
Model	ZHL-50W-52-S+
Frequency range	50-500 MHz
Gain	47-52 dB
Noise figure	4.5-7.0 dB
DC supply voltage	24-25 V
Max. supply current	9.3 A

More information about this PA can be found in [Mini-Circuits25a].

Power Amplifiers (S-Band)

Note

TODO

Low-Noise Amplifier (VHF/UHF)

For the LNA of the VHF/UHF bands, the Mini-Circuits ZFL-500LN+ model is being used. It operates over a wide frequency range of 0.1 to 500 MHz, making it suitable for communications, test equipment, and signal boosting in weak-signal environments. A picture of this device is available in Fig. 5, the main specs can be seen in Table 5.

_images/zfl-500ln.png — Fig. 5 Mini-Circuits ZFL-500LN+ LNA.

Table 5 Main characteristics of the ZFL-500LN+ LNA.
Characteristic	Value
Brand	Mini-Circuits
Model	ZFL-500LN+
Frequency range	0.1 to 500 MHz
Noise figure	2.9 dB
Gain	24 dB (Min.)
Maximum output power	5 dBm
Input voltage	15 V
Current consumption	15 mA (Nominal)

More information about this LNA can be found in [Mini-Circuits25b].

Software Defined Radio

As presented in Fig. 1, the ground segment also has three SDR transceivers. The deployed model is the USRP N210 from Ettus Research [Ettus Research], a high-performance, networked software-defined radio platform. Unlike single-board designs with integrated RFICs (e.g., AD9361), the N210 features a modular architecture with:

Frequency coverage: DC to 6 GHz (via interchangeable daughterboards like SBX/WBX).
FPGA processing: Xilinx Spartan 3A-DSP 1800 for customizable signal processing.
Host connectivity: Gigabit Ethernet (1 GbE) for high-throughput streaming.
Synchronization: 10 MHz reference clock and PPS input for multi-unit coordination.

The platform supports the USRP Hardware Driver (UHD), enabling seamless integration with GNURadio and other SDR frameworks. A picture of the USRP N210 SDR (with enclosure) can be seen in Fig. 6.

_images/usrp-n210.jpg — Fig. 6 Ettus USRP N210 SDR.

The Table 6 lists the key hardware specifications of the USRP N210 SDR.

Table 6 USRP N210 Hardware Specifications
Category	Specification
RF Performance
Frequency Range	DC – 6 GHz (with compatible daughterboard)
Maximum Bandwidth	50 MHz (25 MHz usable in practice)
ADC Resolution	14-bit
DAC Resolution	16-bit
Processing & Connectivity
FPGA	Xilinx Spartan 3A-DSP 1800
Host Interface	Gigabit Ethernet (1 GbE)
Sample Rate (Complex)	Up to 100 MS/s
Synchronization
Reference Clock Input	10 MHz (external)
PPS Input	Yes (for timing synchronization)
Expansion & Power
Daughterboard Slots	2 (supports SBX, WBX, etc.)
MIMO Capability	Yes (2x2 with secondary USRP)
Power Supply	6–12 V DC (9–12 V recommended)