Multi-constellation and multi-frequency GNSS signals are a reality now and their benefits have been the topic of discussion in the recent past amongst the GNSS user segment at large. However, to conduct an experiment involving multi-constellation and multi-frequency signals without an expensive hardware or to quickly examine the result of an algorithmic modification in the receiver processing for real signals is still a herculean task. This is because of the lack of availability of an easy-to-use platform with customizable, specifically open-source, software. Extending the popular and single frequency GN3S signal sampler product, this paper presents the development effort of a hardware module that can sample multiple wide-band signals across the L-band and an updated open-source receiver software to process the sampled signals, work being carried out at the University of Colorado at Boulder.