Standard RC receivers accepts only 1-2mS PPM signals and your servo travels 90 degree only with this signal. 

This small circuit expanding your servo travel 2 times for 180 degree pan tilt applications, headtrackers or camera mounts.

Features

• 30cm Servo cable with male and female connectors
• expanding the servo signal for 0.5-2.5mS from 1-2mS

Important: 

• Servo resolution reduces 2 times when expanding and this may affects some servos as visible steps on the movement. 
• We are expanding the PPM signal only, your servo must be support 180 degree travel for full range of expander. We are suggesting analog servos for the usage. Because digital ones limitting the input signal between 90-120 degree range.