Vaisala RT20A User Manual
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Vaisala RT20A User Manual

Vaisala RT20A User Manual

Radiotheodolite and digicora
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USER'S GUIDE
Radiotheodolite RT20A and
DigiCORA®
M010117EN-H

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Summary of Contents for Vaisala RT20A

  • Page 1 USER'S GUIDE Radiotheodolite RT20A and DigiCORA® M010117EN-H...
  • Page 2 The contents are subject to change without prior notice. Please observe that this manual does not create any legally binding obligations for Vaisala towards the customer or end user. All legally binding commitments and agreements are included exclusively in the applicable supply contract or Conditions of Sale.

  • Page 3: Table Of Contents

    Standard RT20A Sounding Procedure ....... 12 Step 1: Powering Up the System .......... 12 Setting Station Position ............13 Step 2: Aligning the RT20A ........... 15 Step 3: Starting a New Sounding.......... 15 Step 4: Preparing the Balloon ..........15 Steps 5 and 6: Entering Calibration Coefficients....
  • Page 4 USER'S GUIDE____________________________________________________________________ Automatic Termination ............35 Manual Termination.............38 CHAPTER 4 HAND TERMINAL RTH21................41 General Information.............41 Angle and Phase Display Modes ........43 Tune Display Mode..............44 Command Display Mode .............45 Additional Commands of the Angle and Phase Modes..46 Antenna Home Position Command......46 Monitoring Tilt Angles..........47 Setting the Display Back Light ........48 Monitor PTU Command Display........48 Setting the Keyboard Light........49...

  • Page 5: Chapter 1 General Information

    RS80 Radiosonde User's Guide M210487EN DigiCORA® Installation Manual M210488EN DigiCORA® User's Guide M210489EN DigiCORA® Technical Reference M210583EN Maintenance Documentation M210540EN Metgraph for DigiCORA® User's Guide M210551EN STANAG Messages DigiCORA® User's Guide M210987EN Vaisala Radiosonde RS92-D User's Guide VAISALA ________________________________________________________________________ 5...

  • Page 6: Feedback

    USER'S GUIDE____________________________________________________________________ Feedback Vaisala Customer Documentation Team welcomes your comments and suggestions on the quality and usefulness of this publication. If you find errors or have other suggestions for improvement, please indicate the chapter, section, and page number. You can send comments to us by e- mail: manuals@vaisala.com...

  • Page 7: License Agreement

    Chapter 1 ________________________________________________________ General Information License Agreement All rights to any software are held by Vaisala or third parties. The customer is allowed to use the software only to the extent that is provided by the applicable supply contract or Software License Agreement.
  • Page 8 USER'S GUIDE____________________________________________________________________ This page intentionally left blank. 8 ___________________________________________________________________ M010117EN-H...

  • Page 9: Chapter 2 Product Overview

    This chapter introduces the product features. Introduction to DigiCORA and RT20A The basic RDF (Radio Direction Finding) wind finding system consists of the - radiotheodolite RT20A (with hand terminal RTH21 and elevation unit RTE21) - sounding workstation (DigiCORA) - power distribution unit (RPC)
  • Page 10 USER'S GUIDE____________________________________________________________________ This page intentionally left blank. 10 __________________________________________________________________ M010117EN-H...

  • Page 11: Chapter 3 Operation

    Getting Started NOTE These operation instructions apply only to soundings in RDF mode, that is, performing a sounding with radiotheodolite RT20A. When using GPS or Loran-C mode, refer to the instructions in the DigiCORA User's Guide. These instructions presume that:...

  • Page 12: Standard Rt20A Sounding Procedure

    RT20A. Detailed operating instructions are given in the same order in the sections below. NOTE Note that the numbered list introduces the standard sounding procedure tasks usually performed with RT20A. The tasks vary according to the sounding system configuration. Power up the system.

  • Page 13: Setting Station Position

    Station Position dialog, presented in Figure 2 on page 14. If you choose to enter the default station position values manually, you will automatically be asked to enter the default station position values when you start the first sounding. VAISALA _______________________________________________________________________ 13...
  • Page 14 USER'S GUIDE____________________________________________________________________ To manually enter Station Position settings: Select Tools - Station Position – RT20 to open the Station Position dialog. 0203-121 Figure 2 Station Position Dialog If the MWG or MRG card is not available, clear the selection from the Autom.

  • Page 15: Step 2: Aligning The Rt20A

    Chapter 3 ________________________________________________________________ Operation NOTE Check the leveling of the antenna. If the RT20A has been installed on soft or uneven ground, the ground may yield under the antenna legs and the leveling must be corrected. Step 2: Aligning the RT20A...

  • Page 16: Steps 5 And 6: Entering Calibration Coefficients

    USER'S GUIDE____________________________________________________________________ Steps 5 and 6: Entering Calibration Coefficients The procedures for entering calibration coefficients for radiosonde RS92- D and RS80-67 are described below. RS92-D When entering calibration coeffients for radiosonde RS92-D with a radiosonde cable, it is also possible to recondition the radiosonde, or to perform a ground check (when reading coefficients via Ground Check Set GC25) after reading the coefficients.
  • Page 17 Set the frequency by typing it into the Frequency box or by dragging the slider with the mouse, or with the left and right arrow keys on the keyboard. Click Next to proceed. VAISALA _______________________________________________________________________ 17...
  • Page 18 USER'S GUIDE____________________________________________________________________ Radiosonde reconditioning (optional): If the radiosonde is connected to the workstation via cable, it is now possible to recondition the radiosonde. Radiosonde reconditioning is optional, see DigiCORA User’s Guide for details. The reconditioning lasts for 3 minutes. If you do not recondition the radiosonde, click Next to proceed. The sounding system is initialized and a request to perform a ground check appears.

  • Page 19: Radio

    - The Find signal button locates the strongest signal in the frequency band and sets the radio to that frequency. The radio frequency can also be set using the Radio view. VAISALA _______________________________________________________________________ 19...
  • Page 20 USER'S GUIDE____________________________________________________________________ 0312-154 Figure 7 Reading Coefficients via Radio Once the radio is set to radiosonde frequency, the coefficients are read via telemetry. 0312-155 Figure 8 Coefficients Read Successfully via Radio The coefficients have been read successfully. Click Next. 20 __________________________________________________________________ M010117EN-H...

  • Page 21: Rs80-67

    Select the radiosonde type of the radiosonde whose calibration data was read in, or, if you want to use another radiosonde, select Back and read in the red tape of the other radiosonde. Click Next. 0408-008 Figure 9 Radiosonde Selection VAISALA _______________________________________________________________________ 21...
  • Page 22 USER'S GUIDE____________________________________________________________________ When using an analog radiosonde, set radio frequency using the Radio view at this point. The Radiosonde properties window presented in Figure 10 opens. Click Next. 0408-009 Figure 10 Radiosonde Properties Power up the radiosonde. 22 __________________________________________________________________ M010117EN-H...

  • Page 23: Step 7: Selecting Triggering Profiles

    Select the triggering profiles for the sounding (see Figure 11) . By default, the options VoiceNotifications and WMOmessages are selected. To disable message spooling for this sounding, select the Disable Spooling check box. 0301-014 Figure 11 Profiles Window VAISALA _______________________________________________________________________ 23...

  • Page 24: Step 8: Entering Station Data And Front Direction Angle

    USER'S GUIDE____________________________________________________________________ Step 8: Entering Station Data and Front Direction Angle Before the sounding is started, the system needs to know its position. The Sounding Station Position window is used for inputting this data. The default values shown in this window are read from a database. To change the Station position settings select Tools - Station position –...
  • Page 25 For example, if the angle is 355°30', key in 355.50. 0203-081 Figure 13 RDF Front Direction Angle After entering the station data or angle, the program asks you to select the starting mode for the sounding. See Figure 14. VAISALA _______________________________________________________________________ 25...
  • Page 26 - Automatic: DigiCORA detects the launch automatically from the change in the measured pressure. - Manual: The launch is keyed in at the launch time. With RT20A, check Manual and start the sounding by clicking Manual Start on the hand terminal.

  • Page 27: Steps 9 And 10: Tuning The Receiver And Setting Rt20A In Auto Tracking Mode

    Chapter 3 ________________________________________________________________ Operation Steps 9 and 10: Tuning the Receiver and Setting RT20A in AUTO Tracking Mode NOTE Tuning the receiver is for RS80-67 only. The receiver can be tuned either with the sounding workstation or the Hand Terminal RTH21. Usually the receiver is automatically tuned with the sounding workstation, but if you need to tune the receiver manually just before the launch, the hand terminal can be useful.
  • Page 28 Step 11: Releasing the Balloonon page 32. NOTE It is recommended to use the Track mode in the beginning of the sounding with RT20A. The AFC mode should be selected about 10 minutes after the release, especially if the signal is weak. 28 __________________________________________________________________ M010117EN-H...

  • Page 29: Sounding Status Displays

    The PTU field shows the raw PTU values sent by the radiosonde. In Figure 18, for example, the pressure is 1003.6 mbar, temperature is 21.4 °C, and relative humidity is 19.7 %. 0203-086 Figure 18 PTU Status Display VAISALA _______________________________________________________________________ 29...

  • Page 30: Rdf Status

    The RT20A tracking is based on the phase offset values. The RT20A periodically turns to the radiosonde’s direction to keep the values around zero.
  • Page 31 Chapter 3 ________________________________________________________________ Operation The values in the Tilt frame show the inclination angle (alignment difference from the vertical) of the RT20A pole. Both readings are in degrees. The N/S reading is the inclination in north-south direction, and the E/W reading is the inclination in east-west direction. During the operation the inclination values should be less than 8 degrees.

  • Page 32: Step 11: Releasing The Balloon

    USER'S GUIDE____________________________________________________________________ Step 11: Releasing the Balloon After the receiver has been tuned, DigiCORA sounds an alarm and the text "Ready for sonde release!" can be seen on the display. To enter the surface observation values before the launch, click Surf. obs. 0312-171 Figure 20 Ready for Release...
  • Page 33 Enter the surface observation values and click Next to proceed. 0210-050 Figure 21 Surface Observation Values If necessary, enter the cloud group information and additional surface observation values and click Next. 0312-173 Figure 22 Additional Surface Observation Values VAISALA _______________________________________________________________________ 33...
  • Page 34 USER'S GUIDE____________________________________________________________________ Check that the RT20Aantenna follows the radiosonde. The antenna moves stepwise. After each elevation and/or azimuth correction, the radiosonde should be visible through the optical telescope. If the antenna tracks but the radiosonde is not visible through the optical telescope: - Point the antenna manually to the radiosonde using the direction keys on the Hand Terminal RHT21.

  • Page 35: Step 12: Tasks During Flight

    Automatic Termination Sounding observations end automatically when the balloon bursts and the program detects an increase in pressure as the radiosonde falls. EDT calculation is finished, raw data is still received. Click Next to stop the sounding. VAISALA _______________________________________________________________________ 35...
  • Page 36 USER'S GUIDE____________________________________________________________________ 0203-096 Figure 23 Automatic Termination You will receive a request to add the sounding to the Climat statistics, see Figure 24 below. Click Next to perform Climat. 0203-125 Figure 24 Request to Climat You will receive a request to archive the sounding. Click Next to archive. 36 __________________________________________________________________ M010117EN-H...
  • Page 37 If you click Cancel in 30 seconds, your session will be left open and you can use graphical tools to analyze the archived data. Otherwise the program closes. Click Next to close the program manually. 0203-098 Figure 26 Closing the Sounding VAISALA _______________________________________________________________________ 37...

  • Page 38: Manual Termination

    Closing the UCP is not the same thing as stopping the sounding manually. When terminating the sounding, set the RT20A to manual tracking mode: Press the MANUAL key on the hand terminal. Press the ENTER key ( ) on the hand terminal.
  • Page 39 Chapter 3 ________________________________________________________________ Operation If the RT20A is left in the same location for a longer period of time without being dismantled, turn the antenna's elevation angle to approximately 90° in order to decrease the wind resistance. If the antenna...
  • Page 40 USER'S GUIDE____________________________________________________________________ This page intentionally left blank. 40 __________________________________________________________________ M010117EN-H...

  • Page 41: Chapter 4 Hand Terminal Rth21

    Connection to the antenna pedestal is made through a shielded spiral cable. The terminal communicates with other units via Arcnet Local Area Network (LAN). The dimensions of the unit are 96 x 160 x 35 mm. VAISALA _______________________________________________________________________ 41...
  • Page 42 HAND TERMINAL RTH21 Figure 28 Hand Terminal RTH21 The hand terminal has two interfaces to the RT20A, the display and the keypad. With the keypad you can monitor and command the RT20A in the following three modes: - ANGLE mode. The terminal displays the mechanical angles of the RT20A.

  • Page 43: Angle And Phase Display Modes

    With the phase display, use the direction keys on the hand terminal to manually control the antenna. When the RT20A is in manual mode you can drive the antenna in azimuth and elevation directions with the direction keys in all...

  • Page 44: Tune Display Mode

    USER'S GUIDE____________________________________________________________________ three modes, that is, Angle, Phase, and Telem. mode. The default speed of the antenna is about 15 deg/sec. You can change the speed using the additional command Speed (see section Monitor PTU Command Display on page 48). You can slow down the antenna movement by pressing the direction and SLOW SPEED keys simultaneously.

  • Page 45: Command Display Mode

    When the MORE command is reached, the flashing point moves back to the starting point (Home) only with the key. When MORE has been selected and there are no more submenus, the main menu will be displayed again. VAISALA _______________________________________________________________________ 45...

  • Page 46: Additional Commands Of The Angle And Phase Modes

    With the Home command you can drive the antenna to home position, which has been stored previously in the non-volatile memory of the RT20A. When the Home command is selected, the RTH21 displays a confirmation menu for the actual driving. The default selection is No.

  • Page 47: Monitoring Tilt Angles

    (antenna side) and left (from back view) produce negative readings and tilt directions towards back and right produce positive readings. If the RT20A is not equipped with optional tilt sensors, Tilt monitoring shows near zero readings for both values. NOTE Use the Angle, Phase or Telem.

  • Page 48: Setting The Display Back Light

    USER'S GUIDE____________________________________________________________________ Setting the Display Back Light With the BL command you can change the intensity of the keyboard back light. Use the cursor keys to increase or decrease the light intensity. Accept the desired setting by pressing the ENTER ( ) key. Use the CLR key to return without changing the setting.

  • Page 49: Setting The Keyboard Light

    Use the cursor keys to enable (Yes) or to disable (No) the keyboard beep. The selected beep setting is accepted and stored by pressing the ENTER ( ) key. Use the CLR key to return. VAISALA _______________________________________________________________________ 49...

  • Page 50: Manual Driving Speed Command

    USER'S GUIDE____________________________________________________________________ Figure 47 Beep Command Submenu Manual Driving Speed Command Change the speed of the antenna by selecting the Speed command when the antenna is controlled with the hand terminal. The display flashes the current speed which can be changed with the keys.

  • Page 51: Calibration Command

    When you select Calibrate the following submenu appears. You can now calibrate either the elevation synchro or the phase measurement system. Each RT20A has been calibrated at the factory before delivery, so there is normally no need for calibration. When and how the calibrations will be carried out is explained in the RT20A Service Manual.

  • Page 52: Sethome Position Command

    When the elevation angle has been keyed in and entered with the key, the antenna immediately turns to the desired position. NOTE The Pos.Selection command is allowed only when the RT20A is in manual mode. Figure 52 RTH21 Requests Azimuth Direction Position...

  • Page 53: Set Zero Azimuth (Setzeroaz) Command

    Set Zero Azimuth (SetZeroAz) Command With the SetZeroAz command you can store the desired antenna azimuth direction as zero in the non-volatile memory of the RT20A. To set the zero azimuth direction, drive the antenna to the desired azimuth direction and select SetZeroAz from the command menu. The RTH21 displays a confirmation menu for the actual saving.

  • Page 54: Set Receiver Frequency Command Display Mode

    USER'S GUIDE____________________________________________________________________ from ON to OFF state or vice versa with the keys. The current selection is sent to the receiver processor by pressing the ENTER key Now the new AFC mode is selected and the display returns to normal mode.

  • Page 55: Keypad

    In this mode the DOWN ( ) key serves as the ENTER key. Display Keys Display keys such as ANGLE, PHASE, and TELEM., change the mode of the display. The function of the CMD key is determined by the current display mode. Receiver (TELEM.) keys, TRACK, SCAN, TUNE UP VAISALA _______________________________________________________________________ 55...

  • Page 56: Manual Start Key

    USER'S GUIDE____________________________________________________________________ and TUNE DOWN keys, are active only when the Telem. display mode is selected. - TRACK key sets the Track mode to ON or OFF state. NOTE: When the track mode is set OFF, the receiver automatically sets the AFC - SCAN.

  • Page 57: Auto/Manual Key

    Phase mode is selected. For details, see section Angle and Phase Display Modes on page 43. Figure 62 RTH21 Waiting Operator Action (Press Enter) CLR (Clear) Key The CLR key’s function is determined by the current display. VAISALA _______________________________________________________________________ 57...
  • Page 58 USER'S GUIDE____________________________________________________________________ 58 __________________________________________________________________ M010117EN-H...
  • Page 59 www.vaisala.com...

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