This paper discusses ALOHA packet systems with and without slots, focusing on their capacity and performance. ALOHA is a protocol where devices transmit packets randomly over a shared channel. Abramson showed that the effective capacity of such a channel is 1/(2e). However, in practice, capture effects can improve performance. Capture occurs when a stronger signal dominates a weaker one, with a capture ratio of 1.5-3 dB. The paper analyzes the impact of distance and power variations on capture. The paper derives formulas for the average probability of correct packet reception (q) and the effective channel utilization (σ). It considers two cases: asynchronous and synchronous. In asynchronous systems, m=2, while in synchronous systems, m=1. The paper also discusses slot-based systems, where packets are transmitted in time slots, improving performance by reducing collisions. The paper compares asynchronous and synchronous systems, showing that synchronous systems can achieve twice the capacity of asynchronous systems. It also discusses other population densities, such as long narrow strips or circular areas with decreasing density, and shows that the solution remains similar but with adjustments. The paper analyzes satellite and ground radio systems, noting that satellite systems have higher delays due to the satellite's distance. It also discusses the impact of delay on system performance and the importance of choosing an operating point that balances capacity and delay. The paper concludes that slots can improve capacity by up to 347% for satellite systems and up to 60% for ground radio systems. It also notes that asynchronous systems can work well at low utilization rates, making slots unnecessary in such cases. The paper provides formulas for calculating maximum channel utilization and discusses the importance of delay correction in high-bandwidth systems.This paper discusses ALOHA packet systems with and without slots, focusing on their capacity and performance. ALOHA is a protocol where devices transmit packets randomly over a shared channel. Abramson showed that the effective capacity of such a channel is 1/(2e). However, in practice, capture effects can improve performance. Capture occurs when a stronger signal dominates a weaker one, with a capture ratio of 1.5-3 dB. The paper analyzes the impact of distance and power variations on capture. The paper derives formulas for the average probability of correct packet reception (q) and the effective channel utilization (σ). It considers two cases: asynchronous and synchronous. In asynchronous systems, m=2, while in synchronous systems, m=1. The paper also discusses slot-based systems, where packets are transmitted in time slots, improving performance by reducing collisions. The paper compares asynchronous and synchronous systems, showing that synchronous systems can achieve twice the capacity of asynchronous systems. It also discusses other population densities, such as long narrow strips or circular areas with decreasing density, and shows that the solution remains similar but with adjustments. The paper analyzes satellite and ground radio systems, noting that satellite systems have higher delays due to the satellite's distance. It also discusses the impact of delay on system performance and the importance of choosing an operating point that balances capacity and delay. The paper concludes that slots can improve capacity by up to 347% for satellite systems and up to 60% for ground radio systems. It also notes that asynchronous systems can work well at low utilization rates, making slots unnecessary in such cases. The paper provides formulas for calculating maximum channel utilization and discusses the importance of delay correction in high-bandwidth systems.