N2PK says on his website about his vector network analyzer:
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.
reflection measurement capabilities include complex impedance
& admittance, complex reflection coefficient, VSWR, and
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
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.
shows one method on how to solder tiny closely spaced surface-mounted
IC pins. Basically you solder across all pins, then re-heat
and remove most of the solder with solder wick. The solder between
the pins comes off and a very fine layer remains on the metal
Works like a champ. Some say this method has
problems, but it works for me. I first glue the IC down so that
it is perfectly aligned before I solder. The photo below shows
the result when I soldered with this method on my version of
the N2PK VNA.