Radio Lab Final Project

Radio Lab Final ProjectJeremy Ruppert and Lydia Herge

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Our DesignRF Amplifier CS-CE amplifier, with RF choke. (Gain of the CS amplifier is proportional to the resistance seen by the drain. To increase gain, we placed an RFC between the 330 resistor and the drain because it has very high input impedance.)Audio Amplifier LM386 (low quiescent power consumption, high and adjustable gain)Detector stage Complementary Feedback Pair (CFP)

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Soldering board, power LED, 9V battery

Soldering Board BenefitsBesides looking cleaner, a soldering board adds several performance benefits:Soldering reduces impedance by reducing length of leadsMakes better connectionsIn our case, it also unfortunately added some noise, which could be improved upon by adding a filter.

Band Pass Filter

We wanted a way to reduce the noise and improve our signal, so we considered a band pass filter.

Band pass filter decisionWe attempted to use a BPF, and we calculated the correct value of capacitor to select for 1230kHz and roll-off or attenuate all other signals.We found that our radio performed better without it, so we opted not to use it.

With BPFWithout BPFSignal-32.5dB-27.4dBNoise-62.5dB-52.5dB

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Before

After

Success!

Go Braves!!

Possible ImprovementsImplement a band pass filter that effectively attenuates all other signals outside of 1230kHz.Use a board manufactured for the radio as opposed to a generic one.

Questions, comments, compliments?