SeeedStudio SARK-110 User Manual
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SeeedStudio SARK-110 User Manual

Vector impedance antenna analyzer
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SARK-110
Vector Impedance Antenna Analyzer
User's Manual
Revision 1.2.19
Updated to Firmware Version 0.9.x
This document is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
© Melchor Varela – EA4FRB 2011-2020

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  • Page 1 SARK-110 Vector Impedance Antenna Analyzer User’s Manual Revision 1.2.19 Updated to Firmware Version 0.9.x This document is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. © Melchor Varela – EA4FRB 2011-2020...

  • Page 2: Table Of Contents

    VERVIEW OF UNCTIONS ........................7 RECAUTIONS ..............7 ATTERY AINTENANCE AND AFETY UIDELINES ....................9 EGULATORY OMPLIANCE OPERATING THE SARK-110 ....................10 ........................ 10 CREEN AYOUT ....................11 TATUS YMBOLS EANING ........................ 11 EANS OF NPUT ....................12 HANGING THE REQUENCY ......................
  • Page 3 SARK-110 User’s Manual ....................60 IGNAL ENERATOR ....................64 OMPUTER ONTROL ......................66 SPECIAL FUNCTIONS ......................68 ................... 68 RANSMISSION UBTRACT ....................... 71 IRCUIT ODELS 4.2.1 Loop Antenna/Coil ....................71 4.2.2 Capacitor ........................ 73 4.2.3 Quartz Crystal ......................75 4.2.4 Transmission Line ....................

  • Page 4: Introduction

    As a signal generator it is ideal for receiver calibration, sensitivity tests and signal tracing. The SARK-110 features a Direct Digital Synthesis (DDS) generator with a range of 0.1 to 230 MHz and a frequency resolution of 1 Hz. The instrument has full vector measurement capability and accurately resolves the resistive, capacitive and inductive components of a load.

  • Page 5: Main Features

    SARK-110 User’s Manual Please let us have your suggestions through the website http://www.sark110.com as we are highly motivated to extend this device’s functionality, based on community requests. 1.2 Main Features • Pocket size and lightweight • Solid aluminum case •...

  • Page 6: Overview Of Functions

    110 antenna analyzer, while giving you unobstructed access to all connectors and controls. Being made of rubber, the protective rubber case also helps prevent your SARK-110 from damaging glass or polished surfaces. © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...

  • Page 7: Precautions

    SARK-110 User’s Manual 1.4 Precautions 1. Never connect the unit to an antenna during a lightning storm and windy dry days. Lightning strikes and static discharges can damage the unit and may kill the operator. 2. Static build-up on an antenna may cause damage to the unit when connected. As a...
  • Page 8 SARK-110 User’s Manual Even storing a battery in a hot environment can damage it irreversibly. When using your device in a very cold environment, you may notice a decrease in battery life, but this condition is temporary. Once the battery’s temperature returns to its normal operating range, its performance will return to normal as well.

  • Page 9: Regulatory Compliance

    15 minutes, lifting upper and lower lids, until no evidence of the fluid remains. Seek medical attention. 1.6 Regulatory Compliance SARK-110 is certified for CE compliance under regulations EN61000-4-2 and EN55022. © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...

  • Page 10: Operating The Sark-110

    The following figure shows the screen layout in Scalar Chart mode. It shows diagram areas that are the same for all operating modes of the SARK-110. Screen layouts that show specifics for each operating mode are provided in corresponding sections of this manual.

  • Page 11: Status Symbols Meaning

    Disk write operation in progress 2.3 Means of Input There are four buttons and two navigation keys with push-button function on the SARK-110. Navigator A Navigator A is used to navigate within the main menu (left side of the screen). The active option is highlighted with a green background color.

  • Page 12: Changing The Frequency

    User’s Manual Run/Hold [►||] The Run/Hold button is used to control the operating state of the SARK-110: Working or Paused. In the paused state the signal generator and measurement circuits are inactive. ➢ Note: when loading a stored data file the analyzer is automatically placed in a paused state.

  • Page 13: Changing The Span

    SARK-110 User’s Manual (ii) Use Navigator A to highlight «FREQ» in the main menu on the left side of the display. Then use Navigator B to change the frequency. The frequency will change according to the current frequency multiplier. The frequency multiplier can be changed from the popup dialog, see (i) above.

  • Page 14: Changing The Start And Stop Frequencies

    SARK-110 User’s Manual (ii) Use Navigator A to highlight «SPAN» in the main menu on the left side of the display. Then use Navigator B to change the span. The span will change according to the current span frequency multiplier. The span frequency multiplier can be changed from the popup dialog, see (i) above.

  • Page 15: Frequency Presets

    SARK-110 User’s Manual 2.7 Frequency Presets The analyzer provides predetermined frequency and span settings including the amateur radio bands and other suitable settings. Use Navigator A to highlight «PRESET» in the main menu. Press the Select [■] button to activate the Preset popup submenu. Use Navigator B to highlight the desired preset.

  • Page 16: Using Markers

    User’s Manual 2.8 Using Markers The SARK-110 has two markers that can either be manually positioned by the user or set to operate in automatic tracking mode. The markers indicate the horizontal and vertical position of the point on which they are positioned. The horizontal position of a marker is shown by a dotted vertical line which extends from the top to the bottom of the measurement diagram.
  • Page 17 SARK-110 User’s Manual The automatic tracking feature makes positioning of the markers easier, thus helping the user to speed up measurements. The following tracking modes are available: • Peak Min (p) • Peak Max (P) • Absolute Min (m) •...
  • Page 18 SARK-110 User’s Manual For example, you could set Marker 1 to automatically track the minimum VSWR values in the trace: «MARK 1» «Tracking» «Peak Min» «VSWR»; and Marker 2 to track the crossovers on the 50-ohm impedance value: «MARK 2» «Tracking» «Cross Any» «Z» «50.0».

  • Page 19: Changing The Vertical Axis Parameter

    2.9 Changing the Vertical Axis Parameter In Scalar Chart mode, the SARK-110 can display two traces from any of the available parameters for the vertical axis. Use Navigator A to highlight either «LEFT Y» or «RIGHT Y» in the main menu.

  • Page 20: Saving And Recalling Measurements

    Left Y submenu. 2.10 Saving and Recalling Measurements The SARK-110 has the capability to store measurements to the internal disk and recall them either to review the data later in the analyzer screen or to download the data from the USB disk to a PC for further analysis using SARK Plots or the ZPLOTS Excel application, available from http://www.ac6la.com/zplots.html.
  • Page 21 SARK-110 User’s Manual After selecting the «Save Data File» submenu option, enter the file name. By default, the file name has the format “sark__xx.csv” (or “sark__xx.tdr” for Cable Test mode), where xx is an automatically assigned number. To change the file name, use Navigator B to change the character value and Navigator A to change the character position highlighted in inverse video.
  • Page 22 SARK-110 User’s Manual «Load Data File» To retrieve the stored data, select the «Load Data File» submenu option. A second popup submenu is displayed with a list of available files. Use Navigator B to highlight the desired file. Press the Select [■] button to validate the selection. Press any other button to cancel the operation.
  • Page 23 SARK-110 User’s Manual «Load Bitmap File» Use the «Load Bitmap File» option to display a captured screenshot. Press the Select [■] button to finalize the operation. «Browse Bitmaps» Select the option «Browse Bitmaps» from the «FILE» menu to review the captured screenshots.
  • Page 24 SARK-110 User’s Manual When selecting the «Delete All» option, a confirmation dialog box is activated to prevent an accidental deletion. «Deep Sweep Save» The deep sweep save function provides the capability of saving measurements with higher accuracy and resolution. It permits a higher number of frequency points to increase the frequency resolution to be specified and uses the higher accuracy settings during the sweep scan;...
  • Page 25 SARK-110 User’s Manual Enter the number of frequency points. Minimum value is 258 and maximum value is 10000. Specify optional delay automatic start of the measurements (self-timer function). When a Delay is specified, a countdown will commence. Otherwise, press the appropriate button to continue.

  • Page 26: Taking Screenshots

    SARK-110 User’s Manual After completing the sweep scan, the analyzer will save the results of the sweep scan to the file. Notice that the scan time is much longer than usual due to the higher accuracy setting and the additional number of points.

  • Page 27: Changing The Operating Mode

    SARK-110 User’s Manual 2.12 Changing the Operating Mode Use Navigator A to highlight «MODE» in the main menu. Press the Select [■] button to activate the Mode popup submenu; see the screenshot below: Use Navigator B to highlight the desired submenu mode option. Press the Select [■] button to validate the selection.
  • Page 28 SARK-110 User’s Manual Setup – Rotate Screen The Rotate Screen setup menu option can be used to flip the screen so that the device can be used upside down. Use Navigator B to highlight the Rotate Screen submenu setup option. Press the Select [■] button to flip the screen.
  • Page 29 Setup - Scale The SARK-110 provides three pre-defined scale values: Normal, High and Low as well as automatic scaling. This setting defines the maximum and minimum values for each parameter on the Y axis, see Appendix H:.
  • Page 30 SARK-110 User’s Manual Setup - Automatic Power Off This setup permits the automatic power off delay to be selected from a set of predefined times. After power-off, press the Select [■] button to resume operation. Alternatively, power off and power on the device using the Power Switch.
  • Page 31 SARK-110 User’s Manual shutdown state, so the battery could become completely discharged. This could affect its duration and could even be damaged. Setup - Cable Type The length measurements in the cable test mode and transmission line operations require the proper setting of the cable type.
  • Page 32 SARK-110 User’s Manual The screenshots below show how to configure constant Q-lines set at a value of Q of 1. © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12 , 2020 - 32 -...
  • Page 33 SARK-110 User’s Manual Circles can be disabled by selecting «None». Setup – Color Theme This setup permits a choice of two color themes: «Black» or «White». The screenshots below shows graphs with color themes set to «White» and «Black»: © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...
  • Page 34 SARK-110 User’s Manual Setup – Plot Thickness This setup allows a choice of thickness of the diagram’s traces from two options: «Thick» and «Thin». This option is unavailable in the Field Mode graph, where traces are always set to thick.
  • Page 35 SARK-110 User’s Manual Setup – Filter This setup offers the choice of one of two noise reduction filters or none for the Scalar Chart, Smith Chart, Field and Multi-band modes. The «Average» filter minimizes the noise but at the expense of reducing the measurement speed.
  • Page 36 SARK-110 User’s Manual The «Smoothing» filter is a moving average calculation for each measurement point of the unweighted mean of the previous measurement points. The measurement speed is not affected but there could be a loss of accuracy. ➢ The magnitude of the peak or valley of a rapidly changing parameter may be affected.
  • Page 37 SARK-110 User’s Manual Setup – Backlight This setup allows adjustment of the display’s backlight intensity. The range is from 1 to 10, where the higher value corresponds to the higher brightness. Setup – Units This setup allows configuration of distance units either in meters or feet.
  • Page 38 SARK-110 User’s Manual Setup – Stubs This setup allows configuration of the fraction of wavelength and velocity factor for the tuning stubs feature; see section 4.3. Setup – Reset to Factory Defaults This setup permits resetting the analyzer to its default settings.
  • Page 39 SARK-110 User’s Manual The internal disk drive can be optionally formatted. Press the Select [■] button to format the disk or any other button if only a reset to factory defaults is required. It is recommended that the disk contents are backed up to a PC as most of the files will be lost during the format.
  • Page 40 SARK-110 User’s Manual Setup – About The About screen displays copyright information, firmware release number, disk size and free space. © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12 , 2020 - 40 -...

  • Page 41: Operating Modes

    SARK-110 User’s Manual 3 Operating Modes 3.1 Scalar Chart Mode Diagram Frequency and span settings Traces Transmission Line length setting Markers Reference impedance setting Vertical axis labeling Loaded data file name Frequency axis labeling Disk write operation in progress Highlighted menu option...
  • Page 42 SARK-110 User’s Manual selected or automatically tracked. They are also useful for indicating characteristic points in the plot. Use Navigator A to highlight «MODE» in the main menu. Press the Select [■] button to activate the Mode popup submenu and use Navigator B to highlight «Scalar Chart» submenu mode option.

  • Page 43: Smith Chart Mode

    SARK-110 User’s Manual 3.2 Smith Chart Mode Diagram Frequency and span settings Trace Transmission Line length setting Markers Reference impedance setting Constant impedance circle Loaded data file name Frequency start and end Disk write operation in progress Main menu Calibration status...
  • Page 44 SARK-110 User’s Manual The analyzer performs measurements and updates the plot continuously if the Run Mode in the «SETUP» menu is set to Continuous. The sweep can be stopped at any time by pressing the Run/Hold [►||] button. If the Run Mode in the «SETUP» menu is set to Single Shot, the sweep automatically stops on completion.
  • Page 45 SARK-110 User’s Manual © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12 , 2020 - 45 -...

  • Page 46: Single Frequency Mode

    SARK-110 User’s Manual 3.3 Single Frequency Mode VSWR bar Detailed measurements Series impedance complex form Detailed measurements extended Circuit equivalent series Frequency setting Series resistance and equivalent Transmission Line length setting inductance (or capacitance) values Parallel impedance complex form Reference impedance setting...
  • Page 47 SARK-110 User’s Manual Use Navigator A to highlight «MODE» in the main menu. Press the Select [■] button to activate the Mode popup submenu and use Navigator B to highlight «Single Frequency» submenu mode option. Finally press the Select [■] button to enter into Single Frequency mode.
  • Page 48 SARK-110 User’s Manual Select «DISP» «Graphic» for the graphic presentation. Select «DISP» «Big VSWR» for a presentation mode where the VSWR readings are displayed with a big font for easy viewing. © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...
  • Page 49 The stored data in log files includes the index, the relative time in milliseconds, the frequency and the fundamental parameters: -- SARK-110 Data Log -- Z0:50.000000, TL Len:0.000000 ** Start of Log ** ©...
  • Page 50 SARK-110 User’s Manual Index,Time,Freq,VSWR,Rs,Xs,Rp,Xp,|Zs|,<Zs,RL,CL,|Rh|,<Rh,%Rp,Q,Cs,Ls,Cp,Lp 0,26615,13.550000,1.145281,57.027576,-1.778061,57.083015,-1830.818115,57.055290,- 1.785845,-23.385521,11.692760,0.067721,-13.246773,0.458615,0.031179,6605.933594,- 0.020885,6.415576,-21.504335 1,27615,13.550000,1.145240,57.034416,-1.744661,57.087784,-1866.247437,57.061092,- 1.752109,-23.387812,11.693906,0.067703,-12.995469,0.458373,0.030590,6732.399902,- 0.020492,6.293781,-21.920479 2,28615,13.550000,1.144766,57.006538,-1.757563,57.060726,-1850.764648,57.033627,- 1.765921,-23.414286,11.707143,0.067497,-13.140868,0.455587,0.030831,6682.978516,- 0.020644,6.346432,-21.738623 ** End of Log ** © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12 , 2020 - 50 -...

  • Page 51: Cable Test Mode (Tdr)

    Cable Test or Time Domain Reflectometer (TDR) mode is intended to identify potential coaxial cable faults that could disrupt signal transmission. Unlike native TDR test equipment, the method of measurement in the SARK-110 is based on the theory of Frequency Domain Reflectometry (FDR).
  • Page 52 SARK-110 User’s Manual information about the location and the nature of any fault. The impulse response trace (green trace) gives an indication of the fault location. The step response trace (red trace) provides an indication of the nature of the fault.
  • Page 53 SARK-110 User’s Manual Figures below illustrate the responses of known discontinuities: © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12 , 2020 - 53 -...
  • Page 54 SARK-110 User’s Manual Element Impulse Response Step Response Display Open Unity reflection Unity reflection Short Unity reflection, -180º Unity reflection, -180º Resistance R > Z Positive peak Positive level shift Resistance R < Z Negative peak Negative level shift Inductance...

  • Page 55: Field Mode

    SARK-110 User’s Manual 3.5 Field Mode Diagram Frequency and span settings Trace Transmission Line length setting Vertical axis labeling Reference impedance setting Frequency axis labeling Loaded data file name Reading (value and Z) at the center Disk write operation in progress...
  • Page 56 SARK-110 User’s Manual Use Navigator A to highlight «MODE» in the main menu. Press the Select [■] button to activate the Mode popup submenu and use Navigator B to highlight «Field» submenu mode option. Finally press the Select [■] button to enter into Field mode.

  • Page 57: Multi-Band Mode

    The Multiband mode is a unique feature of the SARK-110 to display the plot of an impedance parameter in four scalar charts simultaneously. This feature is ideal for tuning multiband antennas. Additionally, it can be used to display different views of the same band, as a kind of zoom feature.
  • Page 58 SARK-110 User’s Manual Operation is similar to the scalar chart mode but with some limitations such as unavailability of markers and a single trace only. The main menu «BAND» option permits selecting the active band. The selected band is highlighted in the frequency axis of the band graph. Frequency and span settings are applied to the selected band.
  • Page 59 SARK-110 User’s Manual The «Save Data File» function operates in the same way as in other modes. The data for each band of the enabled charts is stored sequentially in individual files. The «Load Data File» loads the data from a file to the selected band only.

  • Page 60: Signal Generator Mode

    User’s Manual 3.7 Signal Generator Mode The SARK-110 can be used as a programmable RF signal source in Signal Generator Mode. It outputs a sinusoidal RF signal at a frequency programmable from 1 kHz to 230 MHz with eight user selectable amplitude levels ranging from -73 dBm to -10 dBm. In addition, frequency sweeps can be programmed with linear, bi-linear, logarithmic, or bi-logarithmic functions.
  • Page 61 SARK-110 User’s Manual The signal generator outputs continuously unless it is paused by pressing the Run/Hold [►||] button. In the Hold state the level graph and power level indicators change to red. Signal generation can be resumed at any time by pressing the Run/Hold [►||] button again.
  • Page 62 SARK-110 User’s Manual The following parameters should be supplied: • Sweep: None Continuous frequency mode Frequency Sweep frequency mode • Repeat: Continuous Continuous signal generation Single Signal generator stops after a single sweep Count: Signal generator stops when number of sweeps reach count ▪...
  • Page 63 SARK-110 User’s Manual All the sweep parameters are shown on the screen as seen in the screenshot below: In Amplitude Modulation mode the signal is 50% modulated with a 1 kHz tone. In Frequency Modulation mode the tone frequency is 1 kHz and the frequency deviation is 2.5 kHz.

  • Page 64: Computer Control Mode

    User’s Manual 3.8 Computer Control Mode The SARK-110 can be operated from a personal computer using SARK Plots client software for Windows, further enhancing the capabilities of the instrument. There is no need to install a dedicated driver since communication is implemented using the standard USB HID interface.
  • Page 65 SARK-110 User’s Manual The command interface specification is open for anyone wishing to develop client software. Source code examples of the communication interface are available for different operating systems. This information is available at the following link: http://www.sark110.com/commands-interface © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...

  • Page 66: Band Scan Mode

    USB/Battery status Highlighted menu option The SARK-110 can be used as a rudimentary Spectrum Analyzer in Band Scan Mode. It can be used to scan for nearby signals that may interfere with the measurements or to measure the power of the spectrum of signals in a lab environment.
  • Page 67 SARK-110 User’s Manual The SARK-110 was not designed as a Spectrum Analyzer so there are a number of limitations when used for this function, such as: • The power level is not calibrated so the measured power levels are not necessarily accurate.

  • Page 68: Special Functions

    4 Special Functions 4.1 Transmission Line Add/Subtract The SARK-110 provides the capability of subtracting a length of transmission line (transpose to load) or adding a length of transmission line (transpose to input). Use the subtraction feature to discount the effect of the feed line so the measurements will be as if the analyzer were connected at the antenna feed point.
  • Page 69 As a precondition the cable must be unterminated at the far end. Set the SARK-110 to Smith Chart mode and select «PRESET» «Full HF». The Smith Chart will show a spiral from infinite impedance and going towards the center. When setting negative length values, this spiral will be progressively unrolled and transposed to the infinite impedance point when the exact length will be set.
  • Page 70 SARK-110 User’s Manual © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12 , 2020 - 70 -...

  • Page 71: Circuit Models

    User’s Manual 4.2 Circuit Models The SARK-110 provides advanced analysis features, including the automatic determination of the circuit models of small loop antennas or coils, capacitors and quartz crystals. It is also capable of automatically determining different parameters having to do with transmission lines.
  • Page 72 SARK-110 User’s Manual Select the file name and press [●] or select [▲] when the results are not to be saved in a file Enter the desired operating frequency After some seconds the results are shown on the screen. A screenshot can be captured by selecting [●]...

  • Page 73: Capacitor

    SARK-110 User’s Manual Self-resonant frequency of the antenna Z(Fop) Z at operating frequency Z(Fra) Z at resonant frequency Equivalent resistance at F = 1 MHz Equivalent inductance at F = 1 MHz Equivalent resistance at the self-resonant frequency The antenna capacitance is calculated with the following equation: ...
  • Page 74 SARK-110 User’s Manual Select the file name and press [●] or select [▲] when the results are not to be saved in a file Enter the operating frequency After some seconds the results are shown on the screen. A screenshot can be captured by selecting [●]...

  • Page 75: Quartz Crystal

    SARK-110 User’s Manual Self-resonant frequency of the capacitor Z(Fop) Z at operating frequency Z(Fra) Z at resonance frequency Equivalent capacitance at F = 1 MHz Equivalent resistance at the self-resonant frequency The capacitor’s parasitic inductance is calculated with the following equation: ...
  • Page 76 SARK-110 User’s Manual Enter the estimated crystal bandwidth value After some seconds the results are shown on the screen. A screenshot can be captured by selecting [●] The figure below describes the measured parameters: The process starts by searching for the series and parallel resonant frequencies. The start scan frequency is taken from the specified frequency value.

  • Page 77: Transmission Line

    SARK-110 User’s Manual     −     The value of the series inductance (Ls) is given by:     Finally, the quality factor of the crystal (Q) is calculated by:  4.2.4 Transmission Line...
  • Page 78 SARK-110 User’s Manual Enter the stop frequency Enter the transmission line length Connect the transmission line terminated with an open circuit. Press the appropriate button to continue, or to exit. Connect the transmission line terminated with a short circuit. Press the appropriate button to continue, or to exit.

  • Page 79: Tuning Stubs

    4.3 Tuning Stubs The SARK-110 facilitates making ¼-, ½ - and other coaxial stubs with the help of Markers Info feature. Markers Info dialog box provides information about the electrical length of the line. Let’s illustrate the tuning procedure with an example. In this case we are going to make a ¼-...
  • Page 80 SARK-110 User’s Manual From the Scalar Chart mode, select start frequency of 1 MHz and stop frequency above the desired frequency –in this case it is set to 30 MHz. Move Marker 2 to the frequency closed to the desired frequency (20 MHz) and select «MARK 2»...
  • Page 81 SARK-110 User’s Manual Cut a piece slightly longer than this value and connect to the analyzer. Move the Marker 1 to the point where <Zs (or Xs) crosses zero. In this case this frequency point is at 16.399 MHz. Select «MARK 1» «Info». The readings show a length of 3.016m and a length difference (M1- M2) of 0.543m, which is the excess length of the piece of coax cable.

  • Page 82: Appendix A: Theory Of Operation

    The block diagram below illustrates the main functional blocks of the SARK-110 Antenna Analyzer: The SARK-110 comprises four main sections: a signal generator used as an active source, a bridge to provide signal separation, two tuned receivers that downconvert and detect the signals and a microcontroller and display for calculating and reviewing the results.
  • Page 83 SARK-110 User’s Manual The output of each of the DDS channels is differential and is amplified by a dual high speed current feedback amplifier working in differential input mode and with output in single ended mode. Most DDS designs use a broadband balun transformer to convert to single end mode but because of the restricted height available in the SARK110 enclosure a silicon-based solution was chosen.

  • Page 84: Appendix B: Fundamental Parameters

    SARK-110 User’s Manual Appendix B: Fundamental Parameters Abbreviation Parameter Description Series resistance Resistive value of a series impedance Series reactance Reactance value of a series impedance Parallel resistance Resistive value of a parallel impedance Parallel reactance Reactance value of a parallel impedance...
  • Page 85 SARK-110 User’s Manual Abbreviation Parameter Description <Rho Reflection It is a measure of the phase angle of the ratio of the Coefficient Angle amplitude of the reflected wave to the amplitude of the (S11 Angle) incident wave.   RhoI ...

  • Page 86: Appendix C: Upgrading The Firmware

    SARK-110 User’s Manual Appendix C: Upgrading the firmware The SARK-110’s firmware may be upgraded via USB as described in the following steps. This procedure assumes have downloaded appropriate update file from: http://www.sark110.com/files/firmware The downloaded file has the following format: SARK110-APP-x.y.z.dfu.zip Where x.y.z is the incremental version number.

  • Page 87: Appendix D: Osl Calibration

    Appendix D: OSL Calibration The SARK-110 provides a calibration procedure to compensate for the stray capacitance and impedance of the external test fixture, e.g. the extension cable. This should be performed every time the external test fixture is changed as well as periodically.
  • Page 88 SARK-110 User’s Manual After selecting the calibration profile, the profile characteristics are shown in a popup dialog. Once the calibration profile has been selected, choose «SETUP» «Calibration» «OSL Calibration» to start the OSL calibration procedure. © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...
  • Page 89 SARK-110 User’s Manual The calibration procedure is as follows: Enter the start frequency (default is the lower frequency limit) Enter the stop frequency (default is the upper frequency limit) Enter an optional name for the profile © Melchor Varela – EA4FRB 2011-2020 Rev 1.2.19 January 12...
  • Page 90 SARK-110 User’s Manual Connect the open load. Load status is indicated by the color of the |Rh| indicator. Green denotes load good status. Press the appropriate button to continue, or to exit. The calibration progress will be shown in the display bar.
  • Page 91 SARK-110 User’s Manual Connect the reference load. Load status is indicated by the color of the |Rh| indicator. Green denotes load good status. Press the appropriate button to continue, or to exit. The calibration progress will be shown in the display bar.

  • Page 92: Appendix E: Frequency Calibration

    SARK-110 User’s Manual Appendix E: Frequency Calibration This setup permits the frequency synthesizer to be calibrated to 1 Hz. The calibration operation is available at «SETUP» «Calibration» «Frequency Calibration». To calibrate the synthesizer, select «Frequency Calibration» from the «Calibration» submenu and adjust the frequency while measuring it with an accurate frequency counter or, alternatively, zero-beat it against WWV.

  • Page 93: Appendix F: Detector Calibration

    Appendix F: Detector Calibration This procedure performs alignment of the SARK-110’s internal measurement circuits. This operation is done once at the factory and it is not necessary for the user to repeat it, but the procedure is detailed for completeness. This procedure comprises a calibration phase and an optional detector-test phase to check the detector circuits.
  • Page 94 SARK-110 User’s Manual The calibration procedure is as follows: Connect the short load. Load status is indicated by the color of the voltage and current detector indicators. Green denotes a load good status. Press the appropriate button to continue, or to exit.
  • Page 95 SARK-110 User’s Manual firmware version v0.9.4 completion screen is slightly different. Press the appropriate button to go to the optional Detector Test, or to exit. Connect the 0-ohm load. Load status is indicated by the color of the voltage and current detector indicators.
  • Page 96 SARK-110 User’s Manual Connect the 100-ohm load. Load status is indicated by the color of the voltage and current detector indicators. Green denotes a load good status. Press the appropriate button to continue, or to exit. Connect the 200-ohm load.

  • Page 97: Appendix G: Frequency Presets File

    SARK-110 User’s Manual Appendix G: Frequency Presets File Default frequency presets can be modified by the user by supplying a special text file stored on the analyzer’s disk. The file name must be “presets.txt” and the format for each band entry in...

  • Page 98: Appendix H: Scale Presets

    SARK-110 User’s Manual Appendix H: Scale Presets The following tables show the default scale presets: Normal Scale High Scale 1000 5000 -500 Linear -2500 2500 Linear 1000 5000 -500 Linear -2500 2500 Linear |Zs| 1000 |Zs| 5000 <Zs -100 Linear <Zs...
  • Page 99 SARK-110 User’s Manual Default scale presets can be modified by the user by supplying special text files stored on the analyzer’s disk. The file names for each of the scales have to be the following: • «Scale» «Normal» → “scal_def.txt”...

  • Page 100: Appendix I: Custom Cable Settings

    Appendix I: Custom Cable Settings The SARK-110 allows the user to specify three custom cable settings by supplying a special text file stored on the analyzer’s disk. The file name must be “custcab.txt” and the format for each cable entry in the file is as follows:...

  • Page 101: Appendix J: Specifications

    SARK-110 User’s Manual Appendix J: Specifications Feature SARK-110 3” Color 400 x 200 pixels Frequency range 0.1 – 230 MHz 1-Hz resolution +- 30-ppm stability Output signal shape Sinusoidal Output power ≈ -12 dBm (measurements) Output power (signal Programmable from -73 dBm to -10 dBm...
  • Page 102 Dimensions 98 * 60 * 14.5 (mm) Weight: 120-g Package contents • SARK-110 x 1 with built-in battery • MCX to SMA female connector adapter x 1 • SMA plug to SMA female 20-cm (8 inches) cable adapter x 1 ©...

  • Page 103: Appendix K: Acknowledgments

    SARK-110 User’s Manual Appendix K: Acknowledgments • I would like to offer a special thanks to the Seeed Studio team for making this product a reality. • The analyzer schematics and layout have been developed using the DesignSpark PCB tool.

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