Funk Amateur FA-VA5 User instructions

A embly and Operating Manual
Kit for an ea y to u e
vector antenna analyzer
for u e in the frequency range
10 kHz to 600 MHz.
Vector
Antenna Analyzer
FA-VA5
Ver E 1.0
25.6.2018

BX-245 • 1© Box 73 Amateurfunkservice GmbH 2018
Radio amateu s who build thei own antennas app eciate the value of avecto antenna analyze . This device is
cha acte ized by high accu acy, small dimensions and easy ope ation. It allows one-po t measu ements in the f e-
quency ange f om 10 kHz to 600 MHz and has a USB po t fo connection to compute s.
Vector Antenna Analyzer FA-VA5
SUPPORT DEPARTMENT OF GERMAN HAM RADIO MAGAZINE “FUNKAMATEUR”
Experiments with antennas make up a sub-
stantial part of the hobby for many radio
amateurs.
The measurement of standing wave ratio
(SWR) and the determination of the
impedance values are inseparable.
The SWR can be estimated when transmit-
ting using aSWR meter, but more exten-
sive and accurate data is obtained using an
antenna analyzer.
However, such instruments are often ex-
pensive whilst cheaper devices often lack
accuracy. The FA-VA5 closes this gap. It
is the successor to the successful FA-VA4
which was also developed by Michael
Knitter, G5MK [1].
The VA5 is afull-featured, vector-measur-
ing device with afrequency range of 10
kHz to 600 MHz, (Table 1) offering com-
pact dimensions and a USB port for con-
nection to acomputer.
Vectorial measurement means that, unlike
ascalar instrument, not only the SWR is
measured and displayed, but also the value
of the impedance, including the signed
imaginary part. The so-called SOL (Short,
pen and Load) compensation, originates
from professional instruments, and is used
for the calibration of the device and pro-
vides precise measurements in different
configurations.
The FA-VA5's graphic display shows the
complex impedance, standing wave ratio,
complex reflection coefficient, capaci-
tance and inductance.
An audible SWR indication using the
built-in piezo buzzer is also available. The
analyser kit consists of an SM -pre-as-
sembled printed circuit board, agraphic
display including backlight, and a USB
module in a specially designed enclosure.
The microcontroller on the board is al-
ready programmed. The USB connection
allows not only the interaction of the FA-
VA5 with Vector Network Analyzer soft-
ware installed on the computer (VNWA
Application – see the corresponding chap-
ter in this manual) but also permits
firmware updates by the VA5 user. The
VA5 Menu structure is easily understood
by newcomers provided you spend alittle
time reading relevant instructions in this
manual. The VA5 kit includes SOL cali-
bration elements, which are usable up to
about 100 MHz. A high-quality calibration
kit, covering afrequency range up to 600
MHz, can be purchased at [1].

2 • BX-245 © Box 73 Amateurfunkservice GmbH 2018
Technical data
Table 1: Technical data
Frequency range 0.01 MHz … 600 MHz, (resolution: 1 Hz)
Measuring range limits SWR ≤ 100, Z≤ 1000 Ω*
Measurement result full impedance value (resistance and reactance), including sign
Accuracy ≤ 2 % (0.01MHz ≤ f≤ 200 MHz, Z< 1000 Ω)
ynamic range Mode Precise: 80 dB to 200 MHz, 50 dB 200 MHz … 600 MHz
of Return Loss Mode Standard: 75 dB to 200 MHz, 45 dB 200 MHz … 500 MHz
Fast mode: 70 dB to 200 MHz, 40 dB 200 MHz … 500 MHz
Frequency stability 0.5 ppm (–30 °C … +85 °C)
Signal processing 24-bit A C, 16-bit SP, 32-bit calculation
Power supply 2 ¥1.5V AA battery
Measuring input 50 Ω, BNC
Output signal Squarewave
f= 1 MHz, RL= 50 Ω:
P1= 5.6 dBm (1st harmonic, fundamental)
P3= –4.0 dBm (3rd harmonic)
P5= –8.3 dBm (5th harmonic)
f= 200 MHz, RL= 50 Ω:
P1= 4.5 dBm (1st harmonic, fundamental)
P3= –7.2 dBm (3rd harmonic)
P5= –15.3 dBm (5th harmonic)
Current consumption 38 mA** (65 mA) at 1 MHz, 47 mA** (85 mA) at 200 MHz,
Load resistance 50 Ω, lighting switched off, single frequency measurement Z
Current real time clock 0.9 μA
imensions 127 mm ¥86 mm ¥23 mm (L ¥W ¥H)
Mass 280 g incl. AA batteries
*Measurements beyond that, but possible with less accuracy
** Mean, peak in parentheses
Important
This construction manual was created
with great care. All hints and advice
contained therein are important for
asuccessful construction! The same
applies to the order of the assembly
steps.
Any revision of the FA-VA5 Assembly
and User manual will be published as apdf
file on www. ox73.de. Please check this
website regularly.
You'll also find videos on assembling and
operating the VA5 Antenna Analyzer once
these are published.

BX-245 • 3© Box 73 Amateurfunkservice GmbH 2018
The following tools are required for as-
sembly:
– temperature-controlled soldering iron
60 … 80 Wwith pencil soldering tip,
– solder 0.5 ..1.0 mm with flux core
– 100 Wsoldering iron with chisel-shaped
soldering tip,
– PCB side cutter pliers
– flat-nose pliers,
– 3mm slot screwdriver,
– Phillips screwdriver,
– two 1.5V AA batteries (Mignon) for
power supply.
Before fitting the board, the contents of
the kit should be checked off against the
parts list in the appendix.
nAssembly of the board
Afew remaining components are to be fit-
ted on the top side of the main board,
i.e. where the six-pin header of the pro-
gramming interface is already located.
The position of the individual parts can be
identified on the assembly plan (Fig. 2).
Switch and USB Interface board
First, the slide switch S1 is soldered to the
topside of the board. It should rest flush
on the board with no space underneath, its
actuating knob must be horizontal with re-
spect to the board surface (Fig. 3). The
easiest way to achieve this is if only one
of the solder pins of the switch is soldered
first. After that, the switch can still be eas-
ily aligned while heating the solder joint.
When the correct mounting position is
found, all pins and the two housing tags
are soldered.
The USB Interface Board is to be soldered
directly to the top side of the main board
with the supplied mica washer inserted for
isolation purposes. The washer must lie
flat and be placed exactly between the cor-
responding soldering surfaces (Fig. 4).
The front edge of the USB socket then
projects slightly beyond the main board to
terminate flush with the housing shell. Tin
Fig. 1: View of assembled FA-VA5 – ower
switched off
Building instructions

4 • BX-245 © Box 73 Amateurfunkservice GmbH 2018
one of the relevant solder pads of the main
board first, then positioned the USB board
including mica washer and fix the USB as-
sembly with some solder. To see if every-
thing fits properly, screw the motherboard
with four M3 screws in the housing lower
shell and then fit on the upper shell. The
USB socket must now sit exactly behind
the rectangular cut-out on the left side of
the housing. If necessary, the accuracy of
fit can now be corrected relatively easily.
If everything is correct then continue and
solder all 16 solder pads of the USB
Board to the main board.
Fig. 3: Slide switch soldered in the correct
position
Fig. 4: USB interface board correctly posi-
tioned
Fig. 2: Assembly plan of the FA-VA5 with components to be fitted
USB module
SG1
battery
battery

BX-245 • 5© Box 73 Amateurfunkservice GmbH 2018
Display
A graphic LC display with integral LE
backlight is used to display the measured
data.
Both components are already delivered as-
sembled as aunit and are only to be sol-
dered in certain places. Caution: Make
sure the display is flush with the LE
backlight so that there is no gap, then pro-
ceed to solder all six connections of the
two three-pin display contacts on the back
of the backlight (Figure 5a). Also solder
the two outer connections of the 20-pin
contact strip (Figure 5b).
It is recommended to use asuitable base
under the display during soldering in order
to fix it flush on the lighting unit.
Caution: The protective film on the glass
surface of the display must first be re-
moved before assembling the housing.
If you forget this, you will see ablack
line on the display that suggests the
glass is damaged.
Fig. 5a: Display with backlight; all six connections must be soldered on top of the backlight
CB
Fig. 5b: View of the 20-pin contact strip of the display after assembly. Only the two outer pins
are soldered on top of the backlight CB. Remove the protective film from the display by
pulling the red tab.

6 • BX-245 © Box 73 Amateurfunkservice GmbH 2018
Socket strips
The three socket strips for contacting the
LC display are fitted next. The pre-assem-
bled display can be used conveniently as a
gauge for their orientation.
Caution: The lower edge of the plastic
body of the socket must have a uniform
distance of exactly 7 mm to the board, to
ensure that the display eventually sits at
the correct height above the main board.
To achieve this, cut the cardboard strip
(supplied in the kit) into four parts and
place it during soldering as shown in Fig-
ure 6a. Before soldering the female con-
nectors, put these strips on the pins of the
display. To do this, place it upside down
on the work surface and carefully slide the
three socket strips onto the display pins.
Make sure the socket strips are flush with
the display board as the 20-pin strip is
prone to bend slightly.
Place the display together with the socket
strips on the board. Next the four card-
board strips are inserted (Figure 6b) then
turn over whole assembly so you can sol-
der the female connectors on the underside
of the board.
The female connectors must be exactly
vertical after soldering.
Push-button switch, piezo buzzer,
battery holders and BNC socket
The three push-buttons, the piezo buzzer
and the battery holders are fitted and sol-
dered next.
Fig. 6a: Four cardboard strips are used for
setting the distance between female con-
nectors and the CB.
Fig. 6b: Main CB view before soldering the female connectors of the LC display; The card-
board strips must be pulled out after soldering, also the display is removed (unplugged)
again before fitting the remaining components.

BX-245 • 7© Box 73 Amateurfunkservice GmbH 2018
Caution: All these components must be
mounted so they sit tight on the main
board. Remove the protective foil of the
piezo buzzer and locate the positive termi-
nal. Fit this component so the positive pin
points in the direction of the battery holder.
Next fit the battery holders, observing cor-
rect polarity (Figure 2). Caution: the
spring contact is the negative pole. The
solder terminals of the battery holders are
made of spring steel. Use suitably robust
side-cutter-pliers to trim the excess length
of the switches, battery holder and buzzer
terminals, making sure that these termi-
nals do not touch the housing later.
Finally, fit the BNC socket and solder on
the board. Again, this part must sit flush and
be aligned horizontally and at right angles
to the edge of the board. The two ground
pins are to be soldered on the underside of
the board with a 100 Wsoldering iron to
ensure the solder flows well in order to
avoid cold solder joints. At the same time,
the soldering time should be kept relatively
short so that the insulation inside the socket
is not damaged (Figure 8). The thin termi-
nals should also be cut after soldering in or-
der to avoid short circuits with the housing.
Functional test and final Assembly
Before installing the board into the hous-
ing, ashort functional test is required. First
fit the three plastic caps on the push-but-
tons and fit the previously assembled dis-
play in the corresponding sockets. Ensure
the slide switch is set to the off position
(Figure 8), then insert two 1.5 Vbatteries
with the correct polarity and switch on the
device with the slide switch.
The start-up welcome message should
now appear briefly on the display, the FA-
VA5 then switches to measuring mode.
If the display remains blank, then all sol-
der joints made in the previous steps must
be carefully checked and reworked if nec-
essary. Once the functional test is complet-
ed, move the slide switch back to the off
position and remove the batteries from
battery holders. The fully assembled board
is shown in Figure 7.
Installation in the enclosure
First, the four rubber feet are inserted into
the lower shell of the en closure. It is helpful
Fig. 7: FA-VA5 Main rinted Circuit Board: fully assembled
Fig. 8: Slide switch in position Off

8 • BX-245 © Box 73 Amateurfunkservice GmbH 2018
to pull with the flat-nose pliers on the thin
rubber nipple on the inside and at the same
time to turn the rubber foot slightly. Then
cut the protruding rubber nipples to 2 mm
with the side cutter (Figure 9) so that they
do not touch the board later. The board is
now inserted by sliding the BNC jack into
the housing lower shell and the four M3
screws are screwed in at the corners of the
board and gently tightened. The BNC
socket must then be screwed together with
the toothed washer and nut and gently
tightened.
To avoid mechanical stresses on the main
board, the four fixing screws of the board
should be loosened and tightened again,
then do the same with the nut of the BNC
socket.
Now insert the batteries observing correct
polarity. Next the housing cover is fitted
and fastened with four M3 countersunk
screws.
Finally, attach the Instrument type label to
the bottom of the housing! The FA-VA5 is
now ready for operation and can already
be used in uncalibrated mode.
General notes on operation
The FA-VA5 antenna analyzer can be used
as ameasuring device immediately after
assembly. It then operates in uncalibrated
mode and the displayed results are subject
to ahigher error than is the case after a
correct calibration. The uncalibrated mode
can always be selected later via the Setup
Menu if, for example, there are doubts
about the validity of the stored calibration
data.
nCautions
Please note the FA-VA5 is a sensitive mea-
suring device. No RF energy should
reach the test socket to avoid destroying
the components at the input! This could
happen when transmitting with the anten-
na connected in close proximity of the
VA5. Likewise, static charges must be
kept away from the test socket. Isolated
antenna structures must therefore be dis-
charged by grounding them first.
Rechargeable batteries should not be
used in the FA-VA5 because there is no
electronic protection against over-dis-
charge and there is no battery charging fa-
cility in the instrument. eep discharge
makes rechargeable batteries useless and
can even destroy them. Leaking batteries
can also cause damage.
The FA-VA5 is designed to make opti-
mum use of 1.5V alkaline cells. In order
to achieve the longest possible battery
life, it is advisable to use the display back-
light only if it is otherwise impossible to
read the display. In daylight or outdoors
the backlight is usually not needed. A
dimmed brightness setting will also help
to save power.
The number of measurements or display
cycles should be selected to produce are-
peat rate that is sufficient for the measure-
ment in question. These parameters can
be changed in the Setup menu and have a
significant influence on the power con-
sumption and thus on the life of the bat-
teries.
It is advisable that BNC plugs should be
turned slightly back and forth after the
bayonet catch engages to improve contact
engagement. Otherwise, under certain cir-
cumstances, “inexplicable” measuring er-
rors may occur.
Fig. 9: Cut rubber feet after insertion into the
housing

BX-245 • 9© Box 73 Amateurfunkservice GmbH 2018
Although the FA-VA5 has arelatively
large range of functions, the operation is
quite intuitive. Therefore, the following
guide has the character of areference
book. However, the general operating in-
structions in the previous section should
always be observed. The instrument can-
not be destroyed by pressing buttons the
wrong way, and at worst this will provide
unexpected or erroneous measurement re-
sults. Therefore, it is recommended that
less experienced users start-off by measur-
ing some components with known values,
then gradually explore the operation of the
antenna analyzer by trying out different
measurement and display modes. If ambi-
guity arises please consult this manual.
For precise measurements, calibration
(SOL compensation) is important. It is
therefore detailed in this independent sec-
tion of the functional description. The an-
tenna analyzer works according to the fol-
lowing principle: An internal oscillator
generates asignal with aspecified fre-
quency, which is routed via the BNC out-
put socket of the device to a test object (for
example an antenna). ue to the electrical
properties of the test object, the test signal
is changed in amplitude and phase. This
change is measured to determine the
impedance relative to known component
values either directly or through the reflec-
tion coefficient (after calibration has been
performed). All other values(e.g. SWR)
are mathematically calculated from the
measured impedance by the built-in mi-
crocontroller.
nControls and Connectors
The only measurement port on the analy-
zer is the BNC connector.
For operation, an on / off power switch
and three press buttons are available. The
Analyzer will always be in the previous
measurement mode after power is
switched on as all parameters are saved
when power is switched off. The three but-
tons have different functions depending on
the selected measuring or operating mode.
In general, afunction is called up or ase-
lection is made with the left push button.
The centre and right buttons are used to
reduce or increase numerical values or to
move through menu lists.
A rapid change of numerical values (e.g.
frequency values for multi-frequency
measurements) can alternatively be ob-
tained by pressing and holding the middle
or right buttons. At any time, the available
functions are displayed on the display
above each of the buttons.
A 2-second long press on the left button
calls up the menu mode in measuring
mode. After that, the middle and right but-
tons allow you to select amenu item
which can then be selected or activated
with the left button. Other button functions
are explained in the following sections.
Power Switch-on
After switching-on power on the FA-VA5,
a start-up message appears on the display,
which includes the firmware version and
the current battery voltage. The factory
default setting of the menu language is
English. The language can be changed to
German by making following button
presses:
Long 2-second press on Left Button: →
Operating Mo e →Centre button: press 7
¥→Setup →1 ¥→Language
→2 ¥→German →left button →
.
Directions for use

10 • BX-245 © Box 73 Amateurfunkservice GmbH 2018
nBasic Calibration
(SOL Compensation)
Each additional connector and cable af-
fects the accuracy of the impedance mea-
surement on the device under test ( UT).
However, these unwanted errors can be
fully calibrated out by the Short pen
Load method (abbreviated to SOL
method).
Three known calibration elements are
measured instead of the test object. The
Short element applies ashort circuit over
the BNC socket, the pen simulates an
open cable end and the Load element pro-
vides aresistance equal to the system
impedance (in our case 50 Ω). The Short,
pen and Load elements supplied with
the FA-VA5 will provide acceptable accu-
racy up to about 100 MHz. You can easily
make your own using three BNC coaxial
cable plugs (50 Ω). To make the Short cal-
ibration element, the inner conductor and
plug housing are short-circuited, whilst in
the pen calibration element the pin of
the inner remains unconnected (see page
37) and the Load element has alow-
impedance 50 Ω SM metal layer resistor
soldered between the inner conductor and
the housing of the plug.
High Quality BNC calibration option
An optional high-quality BNC calibration
set, which can be used up to 600 MHz is
available from [1]. The load element of
this calibration set is individually mea-
sured for highest accuracy and the mea-
sured data is provided in aprinted instruc-
tion leaflet. This data is then entered in the
FA-VA5 Setup menu (see section Calibra-
tion Set ata).
The data supplied for the load element
consists of: picosecond delay, ohms resis-
tance, femtofarad parasitic capacitance,
and nanohenry parasitic inductance.
In addition the delay values for Short and
pen elements should be entered: this is
always – 41.66 ps for the open element
and always – 113.52 ps for the Short ele-
ment.
When using the optional High Quality
Calibration set, all these values must be
entered in Setup →Cal/Port Mo el Mas-
ter and also in Cal/Port Mo el Actual.
Once this data has been entered the master
calibration has to be carried out.
Note: When using the VNWA software,
these individual values can be loaded via
aparameter file. The individual file can be
accessed via the link specified on the in-
struction leaflet supplied with the Calibra-
10 • BX-245
Fig. 10: The kit contains a set of calibration
elements for use in the frequency range up to
about 100 MHz, consisting of a 50 ΩTermina-
tion from Telegärtner (centre) and two BNC
coaxial cable connector for making the Short
and Open reference elements (see text).
A set of Quality BNC calibration elements us-
able up to at least 600 MHz including mea-
surement data report is available under order
no. BX-245-SOL.
Fig. 11: Menu item for SOL compensation for
the actual frequency

BX-245 • 11© Box 73 Amateurfunkservice GmbH 2018 BX-245 • 11
tion kit (CKF file). Loading and using the
CKF file is described in the Help for the
VNWA software.
After completion of the calibration, the
correction values are automatically stored
in the analyzer so that the correct
impedance is determined on subsequent
measurements of the test object.
nBasic Calibration
Three different calibration methods are
available for each measurement mode of
the analyzer:
No Calibration
This is the factory default condition, it can
be accessed through the menu by disabling
the calibration. This option can be enabled
or disabled and is accessed via Operating
mo e →Setup →SOL. Selecting... “Off”
sets the “No Calibration mode”
Current calibration
This can be performed for single-frequen-
cy mode (Figure 11) as well as for multi-
frequency (Figure 11a) and 5-band mea-
surement mode.
The process affects only the actual single
frequency or the frequency range selected
and therefore completes very quickly. Cur-
rent calibration makes it possible to quick-
ly compensate for temporary changes in
the measurement setup or the parameters
due to temperature or other influences.
Caution! Current calibration values are
lost when changing the frequency and
when switching off the analyzer.
Master calibration
It is possible to permanently store SOL
calibration values for the entire measuring
range. The analyzer steps through the en-
tire frequency range with the Short cali-
bration element connected and stores the
measured values. The same process is re-
peated for the pen and the Load ele-
ments. It is recommended to perform the
Master Calibration once directly on either
the BNC connector, or at the end of aper-
manently connected cable or apermanent-
ly connected test setup as part of the ana-
lyzer commissioning process. Once
Master calibration has been performed
measurements can be made at any time
without new calibration.
This Master calibration function can be
accessed via Operating mo e →Setup →
SOL All frequencies (Figure 12). Master
calibration will be selected automatically
whenever the current calibration becomes
invalid.
Caution: Prior to starting Master Calibra-
Fig 12a: Master calibration used in this mea-
surement
Fig. 11a: SOL compensation for the actual Fre-
quencies for a multi-frequency measurement
Fig. 12: Starting point of the master calibration

12 • BX-245 © Box 73 Amateurfunkservice GmbH 201812 • BX-245
tion, do make sure that Cal/Port Model
Master data for Load, Short and Open (if
available) is entered first in Setup, other-
wise the Master Calibration will be invalid.
Note: The Master Calibration process
takes about 20–25 minutes, but can be
cancelled if desired. In this case, however,
inconsistent reference values may arise, so
this calibration should be repeated at the
earliest opportunity.
Which calibration method is actually being
used can be seen on the display. Thus, the
master calibration is used in Figure 12a for
the SWR measurement, recognizable by
the abbreviation M to the right of the bar
graph. After single-frequency calibration,
there would be a Chere (for Current SOL),
whilst an uncalibrated measurement is in-
dicated as a –(dash character) at this point.
nFA-VA5 menu system:
Use the left button to enter the menu
mode (long 2-second button press). Then
there are choices according to Table 2
(Figures 13 and 14). Within the menu, use
the and buttons to move to the
desired point and then select it with the
button. Anew submenu is indicated
by a small arrow > pointing to the right.
The current selection is inverse and slight-
ly indented.
Fig. 13: Operating mode, first part Fig. 14: Operating mode, second part
Table 2: Selection options in FA-VA5 operating mode
Menu item Meaning
Return Return to the previous measurement mode
Single frequency modes SWR, Impedance or Reflection coefficient measurement at current
frequency, SWR measurement with sound signal, current calibration
Multifrequency modes SWR, Impedance or Reflection coefficient measurement within a
frequency range (multi-frequency measurement) in the single or cyclic
run, 5-band SWR measurement, current calibration
Frequency generator RF generator mode
Clock isplays the call sign, the time and the date
USB manual USB mode
ata From Memory isplay and eletion of Saved Measurement Results
( isplay Contents)
Setup Enables the Setup menu (see Table 3)
The system contains three types of menu
items: Measurement Mo es, Functions
and Setup.
The desired Measurement – Operating
mode can always be selected immediately.

BX-245 • 13© Box 73 Amateurfunkservice GmbH 2018 BX-245 • 13
All functions, such as setting of the clock
time or the SOL compensation etc will go
back to the menu from which the function
was called by pressing Return. All set-
tings, e.g. Backlight Mode or isplay Up-
date Cycle, can be selected directly in the
corresponding Setup menu.
nMeasurement Options with the
FA-VA5
The Operating mode allows you to select
the most commonly used measurement
and display settings in practice.
Single Frequency Measurements
The Single Frequency Mo e menu item
is the first of the operating mode selections
and measures either SWR, impedance Zor
reflection coefficient S.
When selecting SWR measurement (Fig-
ure 15) the current measuring frequency
(freq), the standing wave ratio (SWR), the
resistance of the impedance (formula Z),
the reactance of the impedance (+j/-j)
and the SWR are also displayed.
In addition, the reference impedance for
the SWR calculation (here 50 Ω), the type
of calibration used (see section Basic Cal-
ibration) and the impedance model (Sor
P, i.e. serial or parallel) are shown on the
right edge of the display.
The memory indicator S in the upper
right corner of the display indicates that
all changed values have been stored in
the EEPROM of the Analyzer.
When measurement mode SWR1 Frequ
Buzzer is selected, the piezo buzzer pro-
vides abeeping noise during the mea-
surement as an acoustic aid, e.g. for an-
tenna tuning. As the SWR decreases, the
faster the beeps will sound, making it
easy to hear when the lowest SWR is
measured.
The actual measuring frequency can be
set using the three buttons. Use the left
button ( ) to select the point of the
frequency to be changed, indicated by
the underscore or position indicator.
With the middle or right button,
the value of the selected digit is reduced
or increased. You may need to press and
hold the button slightly longer
than usual to change the value.
In the Impedance measurement (Fig.
16), the bar graph is omitted compared
to the SWR measurement. Instead, the
equivalent capacitance or inductance of
the imaginary part for aserial or parallel
replacement element is displayed.
When measuring the Reflection coeffi-
cients (Figure 17), the display shows the
real and imaginary part (S), the magni-
Fig. 17: Single frequency measurement of the
Reflection coefficient
Fig. 16: Single frequency measurement of
Impedance
Fig. 15: Single frequency measurement SWR

14 • BX-245 © Box 73 Amateurfunkservice GmbH 201814 • BX-245
Fig. 19: Additional current calibration option
for the mode SWR 5 frequencies
Fig. 18: Simultaneous SWR measurements
on 5 programmable frequencies
Fig. 19a: Selection of frequency f1
tude and phase angle (phi), the reflection
loss (dB) and Matching Loss (dB).
Within the Single Frequency Mo es menu
item, Current calibration at the set fre-
quency is also possible at any time. After
acquiring the reference values, the Ana-
lyzer returns to the current measuring
mode by selecting Return, if necessary.
Multifrequency measurements
The Multi Frequency Modes menu item
allows the SWR to be measured on five
frequency bands. There is also aSweep
mode to measure SWR, impedance Zand
reflection coefficient S(multi-frequency
measurement). The Sweep mode can be
selected as a single or cyclic run.
SWR measurement on five
frequencies
In SWR 5 Ban mode (Figure 18), five
SWR values are displayed in the bar graph
for five different frequencies.
The actual five frequencies can be entered
or changed in the Setup mode via menu
item 5 Band Frequencies. Figure 19a
shows an example of setting the frequency
ƒ1. It is analogous to setting the measuring
frequency of the Analyzer in Single Fre-
quency Mode. Then press the button
repeatedly until the abbreviation is
shown to the right of the frequency value.
After pressing the or button, you
can move to ƒ2, ƒ3etc. (see also section
Setup). There is no further operating op-
tion in this measuring mode. With this
measurement mode, you can check and
capture the effects of changes made to
multiband antennas in one simple mea-
surement. In addition to the use of master
calibration, current calibration via the
menu item SOL 5 Ban is also possible
for this mode (Figure 19). Prior to per-
forming Current calibration, however, the
five required measuring frequencies must
have been selected first.

BX-245 • 15© Box 73 Amateurfunkservice GmbH 2018
Sweep mode
The Sweep mode (multi-frequency mea-
surement) has three different sub-modes,
which are selected via the left button and
marked with an icon in the upper left cor-
ner of the display. The three sub-modes are
indicated with characters <, >and M
Mode 1: this mode is indicated by charac-
ter <and provides changing of the centre
frequency. The SWR is displayed above
the frequency. In addition, a small rectan-
gle on the SWR curve indicates the posi-
tion of the marker (see sub-mode M). The
centre vertical line corresponds to the in-
dicated centre frequency (7800 kHz in
Figure 20). The full frequency range ex-
tends to the left and right according to the
selected frequency range (here ± 2048
kHz). The middle and right buttons can be
used to reduce or increase the centre fre-
quency by 100 kHz. At the same time, a
new measuring cycle over the specified
frequency range is initiated each time the
button is pressed.
Mode 2: this mode is indicated by charac-
ter >and provides an overview of marker
values and changing of the setting of the
frequency span. Again the SWR is dis-
played above the centre frequency. In ad-
dition, the small rectangle on the SWR
curve indicates the position of the marker
(see sub-mode M). Using the middle and
right buttons, the frequency (sweep) range
can be increased or decreased by afactor
of 2 (within the available frequency or
measuring range). At the same time, anew
measuring cycle over the selected frequen-
cy range is started each time the button is
pressed. The measured value at the marker
frequency is displayed on the bottom right
of the display (Figure 20).
Mode 3: this mode is indicated by charac-
ter M (marker character) and provides a
view and adjustment of marker values
over the previous frequency span. The se-
lected frequency of the marker and the as-
sociated SWR is displayed (without
boundary value limitation). The marker it-
self is again shown as a small rectangle on
the SWR curve. Using the middle and the
right button, the marker can now be
moved along the previous measurement
curve in a total of 100 steps (Fig. 20a). In
contrast to modes <and >, pressing abut-
ton does not trigger anew measuring cy-
cle, but merely displays the changed mark-
er position including the corresponding
measured value.
The measured values obtained before
switching to mode Mwere “frozen” and
can now be “skimmed” using the marker.
Fig. 20a: Multi-frequency measurement of
the SWR; The current marker values are dis-
played.
Fig. 20: Multi-frequency measurement of the
SWR; the arrow on the top left, pointing to
the right shows that an increase or reduction
of the frequency span range can be made
using the plus or minus buttons.

16 • BX-245 © Box 73 Amateurfunkservice GmbH 2018
Anew measured value acquisition takes
place again when switching to sub-modes
1 or 2 indicated by <or >. The combina-
tion of these three sub-modes thus makes
it possible in a simple manner to “ap-
proach” target frequency ranges during
measurements, to narrow them down and
to query specific values at relevant points.
For internal SOL compensation, the in-
strument uses either the calibration values
from the master calibration or or uses the
current calibration values generated via
the menu item SOL Sweep. Prior to per-
forming this calibration, the centre fre-
quency and frequency span must be select-
ed for the current calibration to run
correctly.
Multi-frequency measurements of the
impedance and the reflection coefficient
are in principle similar as when measuring
SWR. The same applies to the operation
of the Analyzer (Figures 20b...20d). In ad-
dition to the single pass, which is only trig-
gered again when ameasuring parameter
is changed on the device, it is also possible
to select the cyclic measuring run (Con-
tinuous Sweep run). This is automatically
restarted by the Analyzer again and again.
Changes in the measured values are there-
fore relatively quickly visible. The disad-
vantage, however, is ahigher power con-
sumption of the device.
Fig. 20b: Example of a multi-frequency mea-
surement the impedance; using plus / minus
buttons the centre frequency of the span
area changes, as indicated by the arrow on
the top left pointing towards the left side.
Fig. 20c: Example of the multi-frequency
measurement the impedance; the real and
imaginary parts are displayed next to the
marker frequency.
Fig. 20d: Example of the multi-frequency
measurement the reflection coefficient, the
result is a small Smith chart; the real and
Imaginary part and other calculated values
are displayed below the marker frequency.

BX-245 • 17© Box 73 Amateurfunkservice GmbH 2018
Fig. 21: Screen display when operating the
FA-VA5 as an RF generator
Fig. 21a: Callsign and time and date dis-
played
Fig. 21b: Display after switching to the USB
mode
nAdditional Operating modes
Frequency Generator
The FA-VA5 operates as a RF generator
with asquare wave output signal at the
BNC socket after selecting the menu item
Frequency generator. Its peak output
voltage is about 1 Vpp to 50 Ω. The actual
signal frequency is displayed (Figure 21).
The frequency setting is made using the
three buttons (choice of decimal point to
be changed with , decrease value
with and increase value with ).
Clock (with Call Sign)
When the menu item Clock is selected, the
set call sign, date and time are shown in
the display (Figure 21a).
USB mode (manual switching)
The menu item USB is also used for man-
ual switching to USB mode (Figure 21b),
see also section Setup.

18 • BX-245 © Box 73 Amateurfunkservice GmbH 201818 • BX-245
Data to and from Memory
Previously saved Screen views and/or
ataset information can be selected here.
All measurement modes allow you to save
ascreen snapshot of the current display
view. To do this, briefly press the left and
right buttons at the same time. In the sub-
sequent screen snapshot menu, one of ten
memory locations (#0 … #9) can be set us-
ing the middle and right-hand
buttons and selected using the left
button. Previously saved views of the se-
lected memory location will be overwrit-
ten. The same is possible on a total of 16
memory locations for ataset records. The
latter can be displayed in the view mode
or transferred to the PC via USB for doc-
umentation purposes (see relevant sec-
tion).
To see these views, select the menu item
Data from Memory →Screen in opera-
ting mo e (Fig. 21c). The corresponding
display memory can be selected with the
and buttons (Figure 22). Un-
used memory locations are displayed emp-
ty. The left button allows you to re-
turn to the previous measuring mode. To
visually distinguish from current measure-
ment results, a saved screen view is dis-
played within a frame (Figure 23).
Fig. 23: A saved screenshot is displayed
within a surrounding frame.
Fig. 21c: Display and delete option for view-
ing or deleting saved Screen and Data infor-
mation
Fig 22: A saved screen display with times-
tamp which can be re-called.