Abstract: A method and apparatus for simulating Loran signals are disclosed herein. The apparatus preferably comprises a portable, solid state testing unit which provides a simulated Loran signal for actuating conventional Loran receivers. The apparatus comprises an oscillator, a divider circuit responsive to the oscillator output for generating first and second trigger signals, and a pulse generator circuit for producing a simulated Loran master signal in response to the first trigger signal and a simulated Loran slave signal in response to the second trigger signal. Means are provided for mixing the simulated Loran pulse and slave signals to provide a composite Loran output signal. The method involved herein comprises the steps of generating simulated Loran master and slave signals and applying them directly to the R.F. front end of the Loran receiver under test, whereby resultant ringing of the receiver tank circuit enables the pulses to be passed through to interiorly located pulse detection and display systems.