PYREX Radio Insulators

Properties of PYREX Radio Insulators
The isolation of radio frequency currents and their confinement within definite circuits demands the use of non-conducting materials possessing an unusual combination of electrical and physical characteristics.
    Radio frequency currents tend to wander and leak over to adjacent conductors, and materials which may offer a fairly effective barrier to the passage of current of low frequency sometimes prove to be conductors, or at least inefficient insulators, at radio frequencies.
    Essential properties for satisfactory radio insulation are low power loss, low surface conductivity, high electrical resistance, a hard smooth surface, stability against corrosive influences, and a high strength-to-weight ratio.
    These properties must remain permanent and unchanged by age, exposure to the elements, and the continued impact of radio energy.
    Performance, which alone has won for PYREX Radio Insulators their present day supremacy, is the direct result of the inherent properties of the glass composition from which they are made.
    The di-electric strength, 35 kv. per 100 mil thickness is higher than that of the best grades of porcelain. The di-electric constant, 4.48 at 30,000 cycles, and the power factor, 0.28% at 30,000 cycles, are lower than those of any other material now available for radio insulation, with the possible exception of pure fused quartz. The surface conductivity is so low as to be practically negligible.
    The specific gravity is 2.25, so that in PYREX Radio Insulators, the dual advantages of light weight and high electrical strength are combined.
    The perfection of surface of PYREX Radio Insulators is an important factor in preserving their continuous efficiency. Except in heavy storms, rain does not form a continuous film on the surface, and as atmospheric dust particles find no pores or cracks for permanent lodgment, a mild rainfall washes away anything which may have settled on the insulator surface.