This is a proposal for a small uplink (ground to balloon) radio system:

• 70cms (434MHz) Ham RADIO transmitter running 10W FM into
• 10dbi yagi
• PC
• packet radio TNC - or soundcard software TNC (such as AGWPE or TrueTTY)

• Good quaility 434MHz “licence exempt” type NBFM module
• Single PIC chip decoder based on N0QBH “simpler” code - See Here

Although the N0QBH decoder does not use DSP techniques the expected preformance should be quite good given the channel is running over FM.

Prototype system built on fibregalss matrixboard 60 x 26 x 12mm - weight 20g (including receiver module).

Good quality: Aim for sensitivity of -120dBm (0.22uV into 50ohm) for 12dB SINAD (signal + noise to noise ratio) and a 6db bandwidth selectivity of 10Khz (-/+5Khz).