BX-240 • 1
© Box 73 Amateurfunkservice GmbH 2017
Radio Amateurs who build their own antennas, appreciate the value of a vector antenna analyzer. The appa-
ratus presented here as a kit, is characterised by high accuracy, small dimensions and easy handling. It allows
one port measurements in the frequency range 100 kHz to 100 MHz with a system impedance of 50 Ohms.
Vector Antenna Analyzer FA -VA4
Experimenting with antennas is an essen-
tial part of the hobby for many radio ama-
teurs. Measuring SWR and determining
impedance values are inseperable. The
first can be estimated with the transmitters
SWR meter, however, better and more ac-
curate data can be obtained by using an an-
tenna analyzer. Good devices are expen-
sive with less expensive models being
somewhat less accurate.
The FA -VA4 closes this gap. It was devel-
oped by Michael Knitter, DG5MK and is
presented in [1]. This is a fully fledged
vector antenna analyzer for use in the
frequency range 100 kHz to 100 MHz
(Table 1).
Vector measurement means that in con-
trast to a scalar measurement, not only is
the SWR determined and displayed but al-
so the value of the base point impedance
along with the sign based imaginary part.
The so called
SOL compensation
from the
professional field is used to calibrate the
device and allows precise measurements
in different configurations.
The FA-VA4 kit consists of an SMD
mounted circuit board, the graphics dis-
play with backlighting, as well as some
mechanical components such as some
connectors, push buttons, sliding switches
and battery holder along with a fully ma-
chined and printed housing. The micropro-
cessor on the board comes pre programmed.
The requirements for construction can be
easily handled by beginners if clean work-
ing practices and adherence to the instruc-
tion manual are followed.
