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[[File:TX circuit modified== Reference ==Here are some reference materials.jpg|alt=Picture This is an initial population of circuit board|left|thumb|Picture of TX circuitmaterial, hilighting components to remove to disable amplifier and a replacement jumperthis section will need significant cleanup - putting links up for now. https://www.weather.gov/media/upperair/Documents/RWS_Build_3.4_User_Manual_%20071818.pdf - Radiosonde Replacement System Workstation User Guide. This manual describes the operational environment of the radiosonde. https://www.nws.noaa.gov/directives/010/pd01014001b.pdf - Rawinsonde Operations - some more technical data on radiosonde operations.]]
Added references; fixed a typo
===Disable amplification===
[[File:TX circuit modified.jpg|alt=Picture of circuit board|thumb|Picture of TX circuit, highlighting components to remove to disable amplifier and a replacement jumper.]]
When testing, it's important not to transmit on unlicensed frequencies. Emissions can be eliminated by replacing the RF amplifier with a jumper between pins 1 and 3, and terminating the load at the antenna connection. The amplifier is an SOT-89 device just above the "-" terminal of B3. To access the RF chain, the shield housing may need to be temporarily removed. Also remove the bias feed resistor just below the "L104" marking. Then, remove the transmitter antenna from the "ANT1" connections. Use a 50 ohm resistor across the two terminals to provide a terminating load and eliminate any further transmission. Near-field reception is still possible after making these changes.
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