In order to address the inevitable need to deploy inexpensive, accurate, reliable sensors that can automatically perform greenhouse gas data collection, the proposed Phase I project builds on the measurement technique described in the paper, "Miniaturized Laser Heterodyne Radiometer for Measurement of Carbon Dioxide CO2 in the Atmospheric Column" by Wilson et al. wherein sunlight is used as the radiometer's signal source. While redesigning the RF receiver in the Mini-Laser Heterodyne Radiometer (Mini-LHR) under a NASA purchase order, Paul Finkel Consulting became familiar with every aspect of the Mini-LHR optical, electrical, software and mechanical design. Along the way, we saw several opportunities to further reduce size and cost, and improve accuracy of the entire system. Likewise, power consumption can be decreased and reliability improved. In the end, the resulting Phase I proof-of-concept system will have fewer moving parts, be lower cost, consume less power important for solar powered installations and will be more compact than the original system and have an accuracy better than 0.3%. Most notably, the product of Phase I will serve as a platform to validate further hardware and software improvements that will be incorporated into a commercial version in Phase II.