Paul Kiciak, N2PK says on his website about his vector network analyzer:

"This is a homebrew VNA capable of both transmission and reflection measurements from 0.05 to 60 MHz, with about 0.035 Hz frequency resolution and over 110 dB of dynamic range. Its transmission measurement capabilities include gain/loss magnitude, phase, and group delay.

Its reflection measurement capabilities include complex impedance & admittance, complex reflection coefficient, VSWR, and return loss.

Unlike other impedance measuring instruments that infer the sign of the reactance (sometimes incorrectly) from impedance trends with frequency, a VNA is able to make this determination from data at a single frequency. This is a direct result of measuring the phase as well as the magnitude of an RF signal at each test frequency."

He has made a wonderful contribution to home experimenters with this excellent circuit design. The quality of supporting documentation is astonishing. PC boards are available and Windows software has been developed by Ian G3SEK, Greg W8WWV and others. See Paul's website for details.

Steve Smith, G8LMX influenced my decision to use a recycled HP equipment cabinet. These can remove much of the work and expense when constructing a home-made project such as this one. There is enough room inside this cabinet to later add the optional dual-detector or even to place an internal NiCad battery pack for field operation.