The paper explores the channel estimation and reconstruction in a Fluid Antenna System (FAS) using Nyquist sampling and maximum likelihood estimation (MLE) methods. FAS, a promising technology for 6G wireless networks, allows radiating elements to switch positions within a predefined space, enhancing diversity and multiplexing gains. However, obtaining full channel state information (CSI) over this space is crucial for optimizing FAS performance. The authors address the challenges of channel estimation and reconstruction, revealing a fundamental tradeoff between the accuracy of the reconstructed channel and the number of estimated channels. They find that half-wavelength sampling is insufficient for perfect reconstruction and that oversampling is essential to enhance accuracy. To balance accuracy and efficiency, they propose a suboptimal sampling distance and bound the channel estimation error within a specific confidence interval. The findings enable the determination of the minimum number of estimated channels and the total number of pilot symbols required for efficient channel reconstruction. Additionally, the paper compares the rate performance of FAS and traditional antenna systems (TAS), demonstrating that FAS with imperfect CSI can outperform TAS with perfect CSI. The analysis is supported by comprehensive simulation results, highlighting the practicality and efficiency of the proposed methods.The paper explores the channel estimation and reconstruction in a Fluid Antenna System (FAS) using Nyquist sampling and maximum likelihood estimation (MLE) methods. FAS, a promising technology for 6G wireless networks, allows radiating elements to switch positions within a predefined space, enhancing diversity and multiplexing gains. However, obtaining full channel state information (CSI) over this space is crucial for optimizing FAS performance. The authors address the challenges of channel estimation and reconstruction, revealing a fundamental tradeoff between the accuracy of the reconstructed channel and the number of estimated channels. They find that half-wavelength sampling is insufficient for perfect reconstruction and that oversampling is essential to enhance accuracy. To balance accuracy and efficiency, they propose a suboptimal sampling distance and bound the channel estimation error within a specific confidence interval. The findings enable the determination of the minimum number of estimated channels and the total number of pilot symbols required for efficient channel reconstruction. Additionally, the paper compares the rate performance of FAS and traditional antenna systems (TAS), demonstrating that FAS with imperfect CSI can outperform TAS with perfect CSI. The analysis is supported by comprehensive simulation results, highlighting the practicality and efficiency of the proposed methods.