Abstract This paper will compare various classes of Loran-C receivers with respect to both price and operating characteristics. It includes a short discussion of the Loran-C system, and then sets out to provide the prospective receiver purchaser with some guidelines to use for evaluation of the commercial market. This should allow the user to optimize his selection of a receiver In order to avoid endorsing or rejecting specific manufacturers' products, only classes of receivers will be discussed, not particular makes and models. INTRODUCTION The Loran-C System Loran-C is a long range radio navigation system that uses the differences in the times of arrival among pulsed 100 kHz transmissions from three or more transmitting stations to provide the system user with a navigation fix. In actual operation of the Loran-C system, each Loran-C chain consists of a master station and at least two secondary stations. At specific time intervals, known as Group Repetition Intervals (GRI's), the master station transmits a group of pulses. After a precisely fixed time delay, one of the secondary stations transmits, and after a different time delay, another secondary station transmits. The user measures the differences in the times of arrival of the master and one secondary, and then the master and another secondary. The locus of all points that have equal time differences between any pair forms a hyperbola. By obtaining two time differences, the user can locate himself on two such hyperbolae. The intersection of the two hyperbolae is his position. There are charts available for most areas in which Loran-C coverage exists that have these hyperbolae drawn on them. Loran-C has been designated as the radio navigation system for use in the Coastal Confluence Zone (CCZ). The East Coast Chain is being reconfigured, the West Coast and Gulf of Alaska chains are being constructed and plans for the Gulf of Mexico Chain are well underway. Coupled with the future shutting down of Loran-A stations in areas where Loran-C coverage exists, these new chains will lead to a widespread increase in the number of users of the Loran-C system. For the most part, they will be uninformed as to what Loran-C is, how it operates, and what user equipments are available to them. This paper will deal with this last area. If the new user of the Loran-C system has a basic understanding of the different types of receiver their intrinsic capabilities and limitations, and the costs associated with them, he can more logically chose a piece of equipment that both fulfills his requirements and still remains within his budgetary constraints. Before going into the actual receiver comparisons, there are several terms that are used further on in the paper that should be defined. The first two terms, envelope and cycle, deal with the Loran-C signal itself. Each transmitting station emits a series of pulses that are closely monitored with respect to amplitude and shape.