Timewave AntennaSmith TZ-900 User manual

TZ-900
Hardware
Manual
AntennaSmith™
Revision 1.2
© Copyright 2006, Timewave Technology Inc., All Rights Reserved

Table of Contents
1. INTRODUCTION ...................................................................................................... 5
1.1. Power On/Off...................................................................................................... 5
1.2. Automatic Power Off.......................................................................................... 6
1.3. Function Modes .................................................................................................. 6
2. SWEEP MODE........................................................................................................... 7
2.1. SETTING SWEEP START AND STOP FREQUENCIES................................ 7
2.1.1. GRAPHICALLY SETTING SWEEP FREQUENCIES ............................ 8
2.1.2. MANUALLY CREATING A NEW SWEEP RANGE.............................. 8
2.1.3. SWEEPING A STANDARD SCAN RANGE ........................................... 9
2.1.4. SWEEPING THE SAME RANGE AS A REFERENCE MEMORY........ 9
2.2.2. SWR.......................................................................................................... 11
2.3. POLAR GRAPH TYPES.................................................................................. 12
2.3.1. SMITH CHART........................................................................................ 12
2.3.2. REFLECTION COEFFICENT (RHO)..................................................... 13
2.3.3. PHASE SIGN CONSIDERATIONS:....................................................... 13
2.4. MEMORIES ..................................................................................................... 15
2.4.1. SCAN MEMORY USAGE: .................................................................... 15
2.4.2. REFERENCE MEMORY USAGE .......................................................... 16
3. MANUAL MODE .................................................................................................... 20
4. HI-RESOLUTION FREQUENCY SYNTHESIZER MODE .................................. 21
5. SYSTEM SETUP...................................................................................................... 22
5.1. Settings.............................................................................................................. 22
5.1.1. Graphic Settings........................................................................................ 22
5.1.2. Smith SWR ............................................................................................... 23
5.1.3. APO Settings............................................................................................. 23
5.1.4. Level Settings............................................................................................ 23
6. POWER SUPPLY..................................................................................................... 24
7. HOST COMMUNICATIONS .................................................................................. 25
8. SPECIAL SERVICE AND SETUP MODES........................................................... 26
8.1. Restoring default settings.................................................................................. 26
9. APPLICATION NOTES .......................................................................................... 27
9.1. Transmission Lines ........................................................................................... 27
9.2. Antenna measurements on coax........................................................................ 28
9.3. Obtaining the best accuracy.............................................................................. 28
9.4 Using the TZ-900 as a sweep generator............................................................ 28
10. QUICK TRICKS................................................................................................... 30
10.1. Rapidly Analyzing an Antenna..................................................................... 30
10.2. Rapidly zooming to a section of a sweep...................................................... 31
10.3. To rapidly set sweep start and stop frequencies using the knob................... 31
10.4. Rapidly setting a scan of 1.000.000 to 30.000.000....................................... 32
10.5. Doing a detailed analysis of a frequency from a sweep................................ 32
10.6. Rapidly starting and stopping a sweep using the same settings.................... 32
11. AntennaSmith™ Connectors ................................................................................ 33
12. Additional Reading ............................................................................................... 34

13. Troubleshooting .................................................................................................... 35
14. Specifications........................................................................................................ 36
15. Timewave.............................................................................................................. 37
16. Warranty ............................................................................................................... 38
17. Table of Figures .................................................................................................... 39
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1. INTRODUCTION
The Timewave TZ900 AntennaSmith™ is a versatile rugged hand-held color
graphical antenna analyzer.
The analyzer has a number of features required for use in a field application.
These features include:
A color graphic display visible in bright sunlight as well as at night.
Memory storage of measurements for reference and/or later download to a
computer through either a USB 2.0 or RS232 type interface.
Color graphic comparison of previously stored measurements. This can be
used for rapid determination of any changes made to the antenna system or for
comparison of antenna system changes over time.
In addition other features include:
Highly stable and accurate direct digital synthesizer frequency generation.
Through the use of one knob and 4 buttons, a simple user interface is provided
requiring a minimum of user inputs to rapidly acquire all of the data available.
An internal fast battery charger guarantees the instrument will always be
available for use.
A 1 Hz resolution frequency generator mode for bench top signal generation.
Remotely controllable by a RS232 serial or USB 2.0 port.
1.1. Power On/Off
The instrument is powered on by pushing and holding the power button until
the opening screen appears.
The instrument is powered off by pushing and releasing the power button or
by having the “APO” (automatic power off) function turn off the unit (see section
1.2).
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After powering the instrument on, the state of the internal battery charge can
be monitored by the battery bar graph indicator. If the indicator shows less than
about 10% green (90% red), it is advisable to connect the fast charger to the
instrument to initiate a fast charge and also guarantee enough power so the normal
measurement accuracy is maintained.
1.2. Automatic Power Off
The instrument has a battery conserving automatic power off mode. This
mode can be selected from the systems settings screen and has four settings (Off,
5 minutes, 10 minutes (default), and 30 minutes). When the instrument does not
receive a user input (either button, knob, USB, or RS232) for the “APO” time
selected, the instrument will automatically turn off.
1.3. Function Modes
There are three major function modes:
The SWeeP mode is a frequency-sweeping mode that graphs chosen parameters
as the frequency is swept from a start frequency to an end frequency. Graphs can
be X-Y type where the X-axis is frequency or polar types such as the Smith chart
or Reflection coefficient.
The MANual mode is used for analysis at a single frequency. This mode uses
bar graphs to display measurable parameters and numeric output on the bar graphs
when acquisition is stopped.
The Hi-resolution frequency SYNTHesizer mode is used to produce a stable
reference frequency that can be used for a number of bench type ham related
activities.
The instrument is switched between the three major modes using the top
“MODE” (#1) button.
The current MODE the instrument is in can be easily determined from viewing
the top button (#1) text. The current mode is shown in green. Modes are labeled
Swp, Man, and Synth on button #1.
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2. SWEEP MODE
The sweep mode provides the user with the ability to rapidly view selected
parameter(s) as the instrument is linearly swept between two chosen frequencies.
Two distinctly different graphic types of sweep are provided. When displaying
single dependent variable resultants, an X-Y type graph is displayed. Polar graphs
are used when two dependent variable resultants are simultaneously displayed.
Sweep type displays
(Single Variable)
SWR vs frequency
Impedance (Z) vs frequency
Real Impedance (R) vs frequency
Imag. Impedance (jX) vs. frequency
(Polar (Two variable))
Smith chart
Rho chart (Reflection coefficient)
Sweep ranges can be manually set, recalled from scan memory, recalled from
reference memory or manually set and saved to scan memory.
Graphics mode (SWR, Z…), and can be changed instantly using the “GRAPH” (#2)
button. The graphics mode is labeled in green on the button.
Upon stopping a running sweep either by pushing the knob or the “STOP SWP” (#4)
button, the sweep frequency range can be manually entered or recalled from the
SCAN or REFerence memories. If old values are OK, simply pushing the knob
restarts the sweep, however if new sweep frequencies are desired, push “SWP
SETUP” (#4) button and follow on screen directions to manually enter a new sweep
frequency range or select from a pre-saved scan memory location.
2.1. SETTING SWEEP START AND STOP FREQUENCIES
There are four methods that can be used to set the beginning and ending
frequencies required for a sweep type graph.
If the graph is currently sweeping --- pushing the “STOP SWP” (#4) button or
pushing the knob will stop the sweep and allow a new sweep range to be set.
At this point the device under test can be disconnected while still preserving the
display.
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(If it is desired to keep using the current range, simply pushing the knob will
restart the sweep.)
Once the sweep is stopped two options are available.
One option is to graphically set the sweep center frequency and the width of the
sweep. This method is rapid and convenient but limited to sweep frequencies that
are within the range currently being displayed on the graph. To use this method
see section 2.1.1.
The second option allows three different non-graphic manual methods. This
option is preferable if it is desired to manually create a new sweeping range
(Section 2.1.2), sweep standard ranges previously saved (Section 2.1.3), or
compare current measurements with a previously saved reference.
2.1.1. GRAPHICALLY SETTING SWEEP FREQUENCIES
If the sweep has been stopped (by pushing button #4 or the knob), a new
center frequency can be selected using the cursor and the “SET Center”
(#3) button. After selecting the desired center frequency with the cursor,
pushing the “SET Center” (#3) button will select the cursor as the center
frequency and display an additional “start sweep” and “end sweep” light
blue pair of cursors. These cursors can be positioned using knob to
accurately set the range of the sweep frequencies to be analyzed. When
the desired sweep width has been made, then the “SET WIDTH” (#3)
button can be used to initiate a sweep with the newly defined sweep
frequencies.
2.1.2. MANUALLY CREATING A NEW SWEEP RANGE
To set a new range it is first necessary to stop the sweep. This can be
accomplished by pushing the “STOP SWP” (#4) button or pushing the
knob. This mode can be identified, as button #4 will be labeled “SWP
SETUP”. Push this button to start manual sweep setup.
The first frequency that needs to be set is the sweep start frequency.
Rotate the knob to set the starting frequency. Pushing the knob will
sequentially step through the digits to be set and the current digit to be
changed will be temporarily shown in RED. To set a frequency less than
1000 kHz push the button to enter the 100 kHz digit after previously
setting the start frequency to 1000 kHz. When first entering the start
sweep frequency mode rapidly rotating the knob to a lower frequency will
rapidly set the lower limit to 1000 kHz for convenience.
After the desired starting frequency is showing in the window
pushing the “SET START” (#4) button will advance to the end sweep
frequency setting mode.
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Use the same technique as setting the start sweep frequency to set
the end sweep frequency. In this case rapidly rotating the knob to a lower
frequency will set the ending sweep frequency to the previously set
starting sweep frequency for convenience. Then rotate the knob to higher
frequencies to set the ending frequency pushing the knob to change the
selected digit. When the desired end sweep frequency has been set,
pushing the “SET END” (#4) button will start a new sweep over the
desired range.
It is possible to save this sweep range before starting the sweep by
using the “SAVE SCAN” (#3) button to enter the scan memory page. Use
the knob to select the memory location desired. At this point pushing the
“STRT SWP” (#4) button will start the sweep with the new endpoint
frequencies that have been saved for easy recall later (See Section 2.1.3—
Sweeping a standard scan range).
2.1.3. SWEEPING A STANDARD SCAN RANGE
To sweep over a previously saved scan range it is first necessary to
stop the sweep. This can be accomplished by pushing the “STOP SWP”
(#4) button or pushing the knob. This mode can be identified as button #4
will be labeled “SWP SETUP”.
Push button “SWP SETUP” (#4) and then “RCL SCAN” (#2) to
enter the scan memory page.
Use the knob to select the desired scan range previously stored.
Push the “STRT SWP” (#4) button to start sweeping over the scan
memory range.
2.1.4. SWEEPING THE SAME RANGE AS A REFERENCE
MEMORY
It is possible to scan and graphically compare results with a
previously saved set of data.
To choose a reference memory scan range it is first necessary to
stop the sweep. This can be accomplished by pushing the “STOP SWP”
(#4) button or pushing the knob. This mode can be identified as button #4
will be labeled “SWP SETUP”
Push “SWP SETUP” (#4) and then “RCL REF” (#3).
Choose the desired reference memory using the knob followed by
the “LOAD REF” (#4) button.
At this point the reference measurement will be displayed.
Pushing the “COMP SWP” (#3) button or the knob will start the
sweep with a colored graphic comparison of the current measurement and
the reference memory data.
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2.2. VARIABLE VS. FREQUENCY TYPE OF GRAPH
The sweep starting frequency is
shown at the bottom left of the graph
while the ending frequency is shown
at the bottom right of the graph.
Two yellow lines are also shown on
the graph. The vertical line is the
cursor, which can be moved using
the knob. The measured value and
the frequency of the cursor location
are displayed above the graph. The
horizontal line is a reference line
provided to assist the user in quickly
analyzing the results. The
frequencies with measured
parameters above the line are shown in red and those below are shown in green.
The location of this line and the span of the y-axis for each graphic type can be set
by the user (See System Setup Chapter 5).
Figure 1: Sweep
If desired, pushing the “MODE” (#1) button while sweeping will switch modes to
the “Manual mode” while automatically transferring the frequency of the current
cursor location to the manual mode for more detailed analysis (See Manual Mode
Chapter 3).
When in the sweep mode, the three lower buttons (#2, #3, #4) are active and let
the user change the sweeping frequencies and other parameters as required.
Button #2 (GRAPH) allows the user to switch sequentially between the six
different graph types. (SWR, Z, Real(R), Imag(jX), Smith Chart, and Reflection
Coefficient). This button is active when in Sweep mode if the sweep is currently
active or stopped.
Button #3 has two functions when in sweep mode. If the analyzer is currently
sweeping, button #3 allows the user to quickly access the reference memory
screen (see REFERENCE MEMORY USAGE Section 2.3.2) so that the current
measurement may be stored as a reference or a previously stored reference can be
loaded. If the sweep is stopped button #3 allows the user to set the new desired
center frequency.
2.2.1. SINGLE VARIABLE GRAPH TYPES
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2.2.2. SWR
The SWR graph displays SWR from the starting to ending sweep
frequency. The y-axis can be varied from 6,11,20,50,and 100 to 1. The
default setting is 6:1 with the horizontal bar set at 2:1. This gives the user a
quick means to determine the 2:1 SWR bandwidth with frequencies meeting
the criteria shown in green and those not meeting the criteria shown as red.
2.2.3. IMPEDANCE (Z)
The Impedance (Z) graph displays impedance of the device under test
from the starting to ending sweep frequency. The y-axis can be varied from
100,200,400,1000, and 2000 ohms and the horizontal bar can be
conveniently placed at any of 9 levels on the graph, as the user prefers.
Frequencies with values above the bar shown in red and those below the bar
are shown in green for user convenience.
2.2.4. REAL IMPEDANCE (R)
This display is similar to the impedance display except only the real
part of the impedance is displayed. Y-axis scale factors for the horizontal
bar settings are the same as described for the IMPEDANCE (Z) graph.
2.2.5. Imaginary (jX)
The imaginary (reactive) component of the impedance is displayed. The
imaginary component can be negative (capacitive) or positive (inductive)
and so this graph is centered about 0. The sign of the imaginary part is
algorithmically determined during the sweep so it is necessary to properly
set up the sweep frequencies so that the sign of the imaginary impedance
will be correctly displayed (see section 2.2.3). In any event, the magnitude
will always be correct. Y scale factors have the same range of settings as
provided for the Impedance graph.
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2.3. POLAR GRAPH TYPES
Two types of polar graphs are provided.
2.3.1. SMITH CHART
Figure 2: Smith Graph
The Smith chart
conveniently provides the
relationship between
frequency, SWR, real and
imaginary components for
the range of swept
frequencies. It is
important to set the sweep
parameters so that the
instrument’s algorithms
can correctly display the
proper polar graphic
(Section 2.3.3).
The cursor provided consists of a small yellow circle encircling the
point defined by the frequency chosen by the knob. This frequency is
provided in yellow letters at the top of the screen while the measured
impedance parameters (real and imaginary) at this frequency are seen in
yellow at the bottom of the graph.
If enabled, a constant SWR circle is provided on the graph and the
SWR this represents is described in red letters at the lower right hand
corner of the graph. Anything falling inside the red circle has a SWR less
than that of the circle’s value with the center of the chart representing a
perfect 50-ohm match and a SWR of 1:1. Corresponding to the horizontal
bars on the X-Y types of graphic displays, the SWR circle value can be set
by the user. Values available are: (None, 1.5:1, 2:1, 3:1, and 5:1). This
feature, if enabled, (SEE SYSTEM SETUP Section 5.0) is allows the user
to rapidly determine if the SWR is low enough to be usable at a chosen
frequency.
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2.3.2. REFLECTION COEFFICENT (RHO)
Figure 3: Rho Graph
The reflection coefficient
graph is used to
determine the angle and
magnitude of the
reflection coefficient over
the sweep range. The
cursor consists of a
yellow circle encircling
the measured point of the
desired frequency and a
vector to the origin.
Values displayed at the
cursor point consist of
frequency, magnitude of
reflection coefficient (0-
1) and the angle of
reflection coefficient (-
180 deg to +180 deg). It
is important to set the
sweep parameters so that
the instrument’s
algorithms can correctly
display the proper polar
graphic (Section 2.2.3).
2.3.3. PHASE SIGN CONSIDERATIONS:
The Smith Chart, Reflection coefficient chart and the imaginary
impedance graph all depend on the algorithmic determination of the sign of
the phase angle. This determination is accurately made in the case of open
or shorted transmission lines, antenna resonance measured right at the
antenna, and most other cases.
However there are instances where multiple resonances occur at
closely spaced frequencies or antennas are measured at the end of a random
length piece of coax, where the algorithm incorrectly determines the sign of
the complex impedance. Where this occurs, that portion of the graph will
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be on the opposite side of the complex impedance half plane but with the
correct magnitude.
To optimize the instrument for proper complex impedance phase sign
determination, adjust the sweep frequencies such that one major resonance
can be seen on the SWR or Impedance (Z) graph before switching to the
Smith or Reflection coefficient graph. Multiple resonance as seen on the
graph within the sweep range chosen will result in multiple cycles of the
sweep being drawn on the Smith or Complex Impedance chart which can be
sometimes confusing to interpret or not have the desired resolution.
It is not uncommon to measure an antenna at the end of a
transmission line. When doing this it is common to see a periodic range of
impedances as a function of frequency. These are caused by the antenna
looking like a high impedance at frequencies other than it was designed to
operate on. Therefore the impedance graph will resemble that of an open
transmission line. To produce a good Smith chart of this situation, simply
center the sweep frequency on the antenna resonance point (or frequency of
minimum SWR) and make the width of the sweep great enough that a
portion of the transmission line impedance can be seen on either side of the
antenna resonant frequency. If the width of the sweep chosen is two small,
it is possible that the phase sign algorithm will not be able to ascertain which
half of the Smith chart some of the impedance points should be on.
Widening the sweep width will allow the software algorithms to correct for
the phase sign in this case. If the sweep width is set too wide, multiple
circular paths will be seen on the Smith and Rho chart. This often results in
a “busy” graph with the points spaced widely thus sacrificing resolution.
With a little practice, it is possible to obtain the desired polar plot by setting
the proper sweep widths for almost all situations.
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2.4. MEMORIES
Two banks of ten memories are available. The first bank is the “SCAN
MEMORIES”. These are used for storing sweep settings for rapid setup.
The second band is the “REFERENCE MEMORIES”. These memories store the
complete data set of the results of a scanned antenna or other device being tested.
This ”REFERENCE” can be used to compare with a future measurement and any
differences will rapidly be observable. All memories (SCAN and REFERENCE)
can be uploaded and downloaded to a RS232 or USB 2.0 connected device.
2.4.1. SCAN MEMORY USAGE:
Figure 4: Scan Memory
10 User selectable scan
memory locations are
available to store
commonly used sweep
settings.
Each scan memory stores
an 8 character name, a
starting frequency, and an
ending frequency.
These memories are set to
default for the standard
amateur radio bands but can
be edited to be anything
desired by the user. All
data is permanently saved
in flash.
To enter the Scan Memory, it is necessary to stop any active sweep (button
#4) and enter the sweep setup screen (button #4)
Pushing button #2 (RCL SCAN) will then display the 10 scan memory
selections possible and one can be chosen using the knob or the “^” (#2)
or “V” (#3) buttons. After selection, pushing the “STRT SWP”(#4)
button will start the sweep. The graph will have the label of the scan
memory name chosen.
To save new sweep settings to scan memory-----
Stop sweep if running (button #4 = “STOP SWP”).
Use the “Swp SETUP” (#4) button to start the process.
Select the starting frequency or accept the one shown.
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Push the “Set Start” (#4) button.
Select the ending frequency or accept the one shown.
Push the “Save Scan” (#3) button.
Using the knob or the “^” (#2) or “V” (#3) buttons select the desired scan
memory location.
Push the “Sel Mem” (#4) button and the data will be saved.
The name of the scan memory will be changed to ‘USER n’ where n is the
scan memory location.
If desired, names can be edited using the “EDIT NAME” (#1) button.
Select the character using the knob, switch which character is being edited
with the “BACK” or “FWD” button.
When done, push the “SAVE MEM” (#4) button to save the name and exit
the edit name mode.
When finished saving a scan memory use the “STRT SWP” (#4) button to
escape back to the sweep screen and restart sweeping using the current
scan memory sweep values.
2.4.2. REFERENCE MEMORY USAGE
10 User selectable reference memory locations are available to store
reference analysis.
Any of the reference analysis can be compared graphically to the current
analysis being performed.
In addition, the reference memory data can be uploaded to a host computer
at a later time so that a history of an analysis performed may be kept.
When using the reference memory compare function, additional colors are
used on the graphical swept display so that the visual comparison of what
has changed is rapidly understood by the user. A ‘semi-transparent’ with
‘highlighted’ values presentation of the reference data aids in a quick
comparison to the new data.
Each reference memory stores an 8-character name, a starting frequency, and
an ending frequency, and the measured data. All data is permanently saved
in flash.
When entering the Sweep mode, it is possible to select one of the reference
memories by using the “RCL REF” (#3) button after using the “Swp
SETUP” (#4) button. This will then display the 10 reference memory
selections possible and one can be chosen using the knob or the “^” (#2) or
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“V” (#3) buttons. After selection, pushing the “LOAD REF” (#4) button
will display the reference memory graphically.
At this point, everything is set up to do a comparison of the reference
memory to what is currently connected to the analyzer. To start the
comparison, simply push the knob. The reference measurements and the
current measurements will be overlaid and simultaneously displayed.
The graph will have the label of the reference memory name chosen.
To save a current analysis to a reference memory:
First, do at least one full sweep of the graph so there is data available
Figure 5: Scan to be saved as a Reference
Next use the “REF MEM” (#3) button to access the reference memory
screen.
Using the knob or the “^” (#2) or “V” (#3) buttons select the desired
reference memory location.
Push the “SAVE REF” (#2) button and the data will be saved.
The name of the reference memory will be changed to ‘Ref. n’ where n is the
reference memory location.
If desired, names can be edited using the
“EDIT NAME” (#1) button.
Select the character using the knob,
switch which character is being edited
with the “BACK” (#2) or “FWD” (#3)
button.
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When done, push the “SAVE REF” (#2) button to save the name and exit the
edit name mode.
When done saving a reference memory use the “LOAD REF” (#4) button to
escape back to the sweep screen which will display the reference memory
graphically.
The reference memory is shown in blue with
a white outline.
By pushing the knob, the analyzer will start
sweeping through the range set by the saved
reference and compare in real time the two
overlaid graphs.
If the current data of the
device being analyzed is
identical to the saved
reference memory, a
picture similar to above
will be displayed. In this
case all of the blue
reference memory is
overlaid with the current
data. Note that the name
of the reference memory
displayed is shown on the
bottom of the graph and the outline of the reference memory is shown by the
white line following the top of the graph.
This figure shows the results of a comparison of
a reference memory and a current scan where
the results are not the same. Notice that you
can easily see the reference and the current
scan as the colors are transparently overlaid.
This case is for demonstration only. Typically
if analyzing the same antenna over time, or a
small adjustment made to an antenna compared
to the reference, only small areas of color
differences will be evident but readily
discernable.
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19

3. MANUAL MODE
Figure 6: Manual Screen
Data acquisition can be started
and stopped using the “ACQ” (#4)
button.
The backlight can be turned on
and off using the “LITE” (#3)
button.
The knob is used to set the desired
frequency. Pushing the knob
allows the user to change the
tuning step size.
There are two options for the bar graph display. The Data (#2) button lets the
user change between Polar or Rectangular coordinates. The current selection is
displayed in green letters on the Data (#2) button.
When in Polar mode the bar graphs display:
SWR 1:1-1:9
Z x 100 0-5
Deg x 10 0-9
When in Rectangular mode the bar graphs display:
SWR 1:1-1:9
Real x 100 0-5
Imaginary x 100 0-5
When acquisition is stopped using the “ACQ” (#4) button bar graph values are
displayed on the bar graph. As acquisition is stopped in this condition real time
data is not being collected and the data shown represents the state when the
acquisition was stopped
Current state of the battery voltage, input charging voltage, processor temperature,
software version and serial number can be determined by simultaneously pushing
buttons (#1) and (#4) when on the Manual screen with acquisition stopped.
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