2 layers26.8 × 19 mm
Ethernet Breakout
UBCOAerospaceClub/LTELink
A base board for the Raxda CM3 to stream live video and telemetry through LTE
4 parts1CERN-OHL-W-2.0
4 layers93.3 × 58.9 mm
LTELink
UBCOAerospaceClub/LTELink1A base board for the Raxda CM3 to stream live video and telemetry through LTE
- Size
- 93.3 × 58.9 mm
- Copper layers
- 4
- Thickness
- 1.61 mm
- Parts
- 107
- Nets
- 341
- Pads
- 768
- Tracks, vias
- 1,154, 334
- Pours
- 18
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 25 Nov 2025
- Updated
- 9 Jun 2026
Overview
LTELink is an open-source printed circuit board by UBCOAerospaceClub, from the UBCOAerospaceClub/LTELink repository on GitHub, published under the CERN-OHL-W-2.0 licence. It is a 4-layer board of 93.3 × 58.9 mm with 107 parts on 341 nets, routed with 1,154 tracks and 334 vias.
It is built around the RTL8305NB-VC-CG, LM29300T-3.3 and AZC199-04S, with the DF40HC(3.0)-100DS-0.4V(51) and X322525MOB4SI among its other parts. Its parts include 41 capacitors, 21 resistors, 16 diodes, 15 connectors and 2 ICs. It belongs with the radio and wireless boards and the Raspberry Pi (Linux) boards of this library.
Main components
5
RTL8305NB-VC-CG
QFN-48(6x6)10BASE-T、100BASE-TX 10Mbit/s、100Mbit/s 3.3V 5 QFN-48(6x6) Ethernet Transceivers ROHSRealtek SemiconEthernet Transceivers
LM29300T-3.3
TO-220-3L-40℃~+125℃@(Tj) 250uA 26V 3.3V 370mV@(3A) 3A 400uVrms Fixed TO-220-3L Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSHTC Korea TAEJIN TechVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
AZC199-04S
SOT-23-6-55℃~+125℃ 0.3pF、0.8pF 11V、15V、18V 300W@8/20us 4.7A@8/20us 5 5V 6V 80nA ESD IEC 61000-4-2、IEC 61000-4-5、IEC 61000-4-4 Unidirectional SOT-23-6 ESD and Surge Protection (TVS/ESD) ROHSTECH PUBLICESD And Surge Protection (TVS/ESD)
DF40HC(3.0)-100DS-0.4V(51)
SMD,P=0.4mm-35℃~+85℃ 0.4mm 100P 2 300mA Gold Slot Type Butting Surface Mount,Vertical SMD,P=0.4mm Board-to-Board and Backplane Connector ROHSHirose ElectricBoard-To-Board And Backplane Connector
X322525MOB4SI
SMD3225-4P-40℃~+85℃ 12pF 25MHz 50Ω Crystal Oscillator ±10ppm ±20ppm SMD3225-4P Crystals ROHSYXCCrystals
README
README.mdLTELink
[!IMPORTANT] This project is a work in progress
LTELink is custom base board design for the Radxa CM3. It main purpose is to connect several IP cameras and other ethernet-connected devices on a drone, and stream their video and telemetry over LTE to a ground station. Additionally, a compatible WiFi adapter could be connected via USB to use WFB-ng for a direct radio link. Video streamed through the LTELink could also be recorded directly to the onboard SD card for a post-flight review.
Hardware Specs
- 1x MiniPCIE slot for LTE modem (Designed for Quectel EC25)
- 1x Nano SIM card slot
- 1x USB 2.0 hosts
- 1x USB OTG interface with manual host/device control
- 4x 100M ethernet (unmanaged)
- 1x Micro SD card slot
- 2x UART connectors
Hardware Block Diagram
Software Stack
- GStreamer for video streaming
- mavp2p for Mavlink routing
- Tailscale for VPN
- Rockchip Media Processing Pipeline for video encoding (if needed)
Parts
107| Qty | Value | Footprint | References |
|---|---|---|---|
| 21 | 100n | Capacitor_SMD:C_0402_1005Metric | C2, C10, C16, C17, C18, C22, C23, C24, C25, C26, C28, C29, C30, C31, C33, C36 +5 |
| 11 | 10u | Capacitor_SMD:C_0603_1608Metric | C1, C6, C8, C9, C11, C12, C13, C19, C20, C21, C27 |
| 8 | AZC199-04S | Package_TO_SOT_SMD:SOT-23-6_Handsoldering | D1, D2, D3, D4, D5, D6, D7, D8 |
| 8 | Conn_01x04 | Connector_JST:JST_GH_BM04B-GHS-TBT_1x04-1MP_P1.25mm_Vertical | J13, J14, J15, J19, J21, J22, J23, J24 |
| 7 | LED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D9, D10, D11, D12, D13, D14, D15 |
| 6 | 510 | Resistor_SMD:R_0402_1005Metric | R5, R7, R9, R10, R22, R24 |
| 5 | 0 | Resistor_SMD:R_0603_1608Metric | R4, R11, R12, R14, R19 |
| 4 | 1p | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C14, C15, C32, C34 |
| 4 | 75 | Resistor_SMD:R_0603_1608Metric | R8, R20, R21, R23 |
| 3 | 33p | Capacitor_SMD:C_0402_1005Metric | C3, C4, C5 |
| 2 | 12p | Capacitor_SMD:C_0402_1005Metric | C41, C42 |
| 2 | DF40HC(3.0)-100DS-0.4V(51) | LTELink:DF40HC(3.0)-100DS-0.4V(51) | J1, J2 |
| 2 | Filter_EMI_CommonMode | LTELink:FILTER-SMD_4P-L4.5-W3.2-TL_ACT45B | FL1, FL2 |
| 2 | TestPoint | TestPoint:TestPoint_Pad_D2.0mm | TP1, TP2 |
| 1 | 1.5k | Resistor_SMD:R_0402_1005Metric | R13 |
| 1 | 15k | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 1759547-1 | LTELink:TE_1759547-1 | J4 |
| 1 | 1k | Resistor_SMD:R_0402_1005Metric | R16 |
| 1 | 2.49k 1% | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R6 |
| 1 | 22 | Resistor_SMD:R_0402_1005Metric | R3 |
| 1 | 350uH | LTELink:SOP-40_L28.1-W12.2-P1.27-LS16.00-BL | L1 |
| 1 | 51k | Resistor_SMD:R_0402_1005Metric | R15 |
| 1 | Conn_01x03 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J5 |
| 1 | D | Diode_SMD:D_SMA | D16 |
| 1 | DF40HC(3.0)-100DS-0.4V(51) | LTELink:DF40HC(3.0)-100DS-0.4V(51)_mirrored | J3 |
| 1 | Fan | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | M1 |
| 1 | Fuse | LTELink:F1206 | F1 |
| 1 | Jumper_2_Bridged | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | JP1 |
| 1 | LM29300T-3.3 | Package_TO_SOT_THT:TO-220-3_Horizontal_TabDown | U1 |
| 1 | Micro_SD_Card_Det1 | LTELink:TF-SMD_TF-009 | J7 |
| 1 | NANO SIM 7P H1.37 | LTELink:SIM-SMD_NANO-SIM-7P-H1.37 | SIM1 |
| 1 | Q_NMOS | Package_TO_SOT_SMD:SOT-23_Handsoldering | Q1 |
| 1 | RTL8305NB-VC-CG | Package_DFN_QFN:QFN-48-1EP_6x6mm_P0.4mm_EP4.4x4.4mm | IC1 |
| 1 | Raxda CM3 | LTELink:CM3 | Raxda |
| 1 | USB_C_Receptacle_USB2.0_16P | LTELink:USB-C-SMD_G-SWITCH_GT-USB-7010ASV | J9 |
| 1 | X322525MOB4SI | LTELink:X322525MOB4SI | Y2 |
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Questions
How big is the LTELink PCB?
It measures 93.3 × 58.9 mm and has 4 copper layers, 1.61 mm thick.
What parts does the LTELink use?
107 parts, built around the RTL8305NB-VC-CG, LM29300T-3.3, AZC199-04S and DF40HC(3.0)-100DS-0.4V(51). The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the LTELink KiCad files?
From the UBCOAerospaceClub/LTELink repository on GitHub, at the commit this page was made from: the board is KiCad/LTELink/LTELink.kicad_pcb and its schematic KiCad/Ethernet Breakout/Ethernet Breakout.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the LTELink design in my own project?
Its repository publishes it under the CERN-OHL-W-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).