The use of sphere gaps at radio frequencies

FOR many years the sphere gap has been used for measuring high voltage at power frequencies1,2 and it is also used for impulse testing. However, at present the sphere gap is not an accepted standard for the measurement of radio-frequency voltages. This is largely attributable to the lack of complete data on the spark-over values of sphere gaps in air, at radio frequencies. Some results have been published3¿6 but they are not altogether consistent and the spectrum of frequencies covered is far from complete.