Amphenol Polyfoam^® Coaxial Cable
January 1962 Radio-Electronics

January 1962 Radio-Electronics [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

Amphenol's introduction of Polyfoam^® dielectric material for coaxial cable represented a big improvement from both signal loss (attenuation) and velocity factor. This 1962 Radio-Electronics magazine advertisement promoted its virtues. Its previous dielectric was solid polypropylene having a dielectric constant of 2.26, whereas Polyfoam^® claimed 1.50. Velocity factor (VF) is proportional to the inverse square root of the dielectric constant (k); i.e., VF = 1/√k. Hence VF_{polypropylene} = 0.620, and VF_Polyfoam^®= 0.816. The lower k value facilitates, for equivalent current handling, a smaller coaxial cable diameter with a lower weight, and is more flexible due to a "softer" dielectric. I could not find a breakdown voltage value for Polyfoam^®, as compared to polypropylene's 30 kv-40 kV. Calculation of the characteristic impedance of a coaxial cable involves many parameters, all of which also affect current, voltage and power handling, physical size, flexibility, minimum bend radius, signal propagations velocity, capacitance, group delay, signal attenuation, and more. Nothing's simple.

Amphenol Polyfoam^® Coaxial Cable

How inert gas bubbles here ...

... give you up to 35% greater signal strength here

When you use Amphenol Polyfoam^® coaxial cable, you consistently increase signal strength up to 35% over ordinarily used RG-/U cable. The secret? It's in the new Polyfoam^® dielectric material - a cellular polyethylene that uses inert gas as the expanding agent to form tiny, completely enclosed cells in the polyethylene. It gives you a dielectric constant of 1.50 as compared with 2.26 for solid polyethylene - for lower attenuation and minimum capacitance.

That's not all! With Polyfoam^® cable, you still utilize minimum diameters. Matter of fact, Polyfoam^® cable actually weighs less than standard RG cables.

You're ahead all these ways - and at surprisingly low additional cost - when you use genuine Amphenol Polyfoam^® for your coaxial cable requirements. See your authorized Amphenol Distributor. If you don't know who he is, write to Amphenol Distributor Division, 2875 S. 25th Avenue, Broadview, Illinois, or call Columbus 1-2020.

Amphenol Distributor Division / Amphenol-Borg Electronics Corporation