LMS-6 Radiosonde
The LMS-6 Radiosonde is a radiosonde manufactured by Lockheed-Martin Sippican, and used for meteorological sounding.
Overview
There are two models of the LMS-6, a 403MHz model and a 1680MHz model. This article will cover the 403MHz model unless specified.
Specs
- 16 Fixed transmit carrier frequencies (MHz): 400.250, 400.625, 401.000, 401.375, 401.750, 402.125, 402.500, 402.875, 403.250, 403.625, 404.000, 404.375, 404.750, 405.125, 405.500, 405.875
- Frequency tolerance +/-30ppm
- Mean TX Power 70.8mW (18.5dBm)
- Emission Designator 16K8F1D
- FSK with a maximum modulating frequency of 4.8 kHz
- Emission 3dB BW +/-5.0 kHz
- Emission 20dB BW +/-12.7 kHz
- Omnidirectional antenna
- Main beam gain 2dBi
- Horizontal Beamwidth 360 degrees
- Vertical Beamwidth +84 degrees
Photos
Connectors
sens 3 - standalone TC
sens 4 - RH TC
| Pin Number | Function |
|---|---|
| 9, 10, 15, 16, 19, 20, 33, 34 | Ground |
| 4 | U3 - Vpp/ICCSEL |
| 5 | U3 - RESET |
| 6 | U3 - ICCDATA |
| 13 | U3 - SW1.4 |
| 17 | U3 - SW1.2 |
| 18 | U3 - SW1.1 |
| 31 | BATT POS |
| 36 | U3 - SW1.3 |
| 38 | U3 - ICCCLK |
| 39 | RED WIRE |
J1 - 4 pin 0.1
- 1 - Black
- 2 - White
- 3 - Red
- 4 - NC
J4 - NC - earphone jack? uses SENS3 leads
J5 - 4-pin 0.1 - to U3 (STM)
SP1 - 2x4pin 0.1 - tu U14 (SPI mem?)
Components
GPS - Trimble 63530-50 s/n 1190122906
https://www.trimble.com/embeddedsystems/copernicus2.aspx
U3 - 72F324J6T6 - ST72324 - Main Microcontroller, ST7 series
U5, U6 - LP2985
U?? - TPS7201Q
U13 - CD4040BPW
U14 - CD74HC4051PWR
U16 - LMV761
U21 - TI/Chipcon CC1050 (TSSOP 24)
U22 - TPS791
Sens 4 - Capacitive Relative humidity sensor
Notes
U13 Package marking shows CM040B. TI Park marking lookup provides CD4040BPW
U16 Package marking shows C22A. TI Part marking lookup provides LMV761. The SOT-23 footprint appears to match what is on the PCB.
Sens 4 is know to be capacitive since it is listed as such on page 13 of the WMO Common Code Tables Document
Circuits
RF from CC to Ant1 - coming soon
Relative Humidity Circuit
File:Relative Humidity Circuit Schematic.pdf
U16 -Input also has a cap to ground not shown on the sketch.