SRX_400 TELEMETRY RECEIVER USER'S MANUAL Version 4.xx LOTEK Wireless Inc. Newmarket, Ontario, Canada E00033 Rev.A Rev B, ECO 302, 31 Mar 2001 Deleted: 3.
Rev B TABLE OF CONTENTS SRX_400 TELEMETRY RECEIVER ........................................................................................................1 USER'S MANUAL VERSION 4.XX ..........................................................................................................1 INTRODUCTION .............................................................................................................3 SRX_400 FUNCTION GUIDE........................................................................
Rev B INTRODUCTION The SRX_400 is a data logging, tracking and telecommunicating receiver designed for a wide range of applications. All of its internal functions are controlled by a dedicated microcomputer with 64k bytes of program memory (EPROM) and 64K bytes of data memory (non-volatile static RAM). Besides its regular housekeeping duties, which are automatic and invisible, the microcomputer provides a number of basic and advanced operations which are accessed through function keys and menus.
Rev B SRX_400 FUNCTION GUIDE Power Supply and Accessories ANT CHG EAR OFF/VOL - RF jack for antenna connection (whip antenna, ASP_8 connection) - Battery charger connection - Headphones connection - On/Off switch, volume control knob POWER - External DC power cable connection ASP_8 - ASP_8 antenna switching unit connection - 15 pin SERIAL I - serial port used for RS232 communications (dumps, terminal control, DSP) - 9 pin SERIAL II- serial port used for DSP_500 interface in versions supporting both DSP
Rev B SRX_400 receivers produced after April 1994 (look for an “A” in the serial number) are equipped with a new power management system which provides true "fast-charging” of batteries, independence of charge and external power functions and a bicolor charge status indicator.
Rev B port (PORT 2), to accommodate special applications (e.g., GPS or DSP_500 interfaces). A 15-pin (DE-15P) connector is also provided for antenna switching using Lotek’s ASP_8 controller. See the figures above for locations of front and rear panel connectors. Maintenance and storage The SRX_400 should be protected from dust and moisture. If cleaning is required, the housing and front panel can be cleaned using a soft cloth. You may need to use cleaning solution.
Rev B new environment (e.g., frequency scan or signal measurement) in which keys may be reassigned and functions redefined. Navigation is guided by interactive menus and the ESCape key. PROM initialization Operating system software is contained in one (SRX_400 ‘A’ models) or two (earlier models) programmable read only memories (PROMs). The SRX_400 can run a variety of different software versions which are specialized for particular applications.
Rev B ENTER GAIN (00-99) > or, in versions supporting individual antenna or channel gains, MASTER GAIN (XX) > (where XX is the current value) and then waits until it receives two numeric inputs from the keypad. Shifted or non-numeric keys (except ESC) are ignored. The system gain is then set according to the received two-digit value. Pressing the ESC (escape) key causes the function to abort without updating. On exit, the command display (frequency and gain) is restored.
Rev B SET ∆ ESC The ESC key is the general "return" operator. Most commonly it returns you to the main program, restoring the command display on line one. Sometimes it provides a return from a subprogram to the menu from which it was called. Sometimes it is used to terminate data entry (of lists or table values) from the keyboard. The SET ∆ ("set delta") key is used to set incremental values of frequency, gain or time for use by the increment and decrement functions (arrow keys).
Rev B The Range function requests a beginning and ending frequency for the search and then scans this range. This function may be used to find the frequency of an unknown transmitter or to check for the presence of any of a known group of signals. The Neighbourhood function searches a range of frequencies from 8KHz below to 8KHz above the current selected frequency.
Rev B SHIFT + SET F, SHIFT + SET G assigns the arrow keys to increment/decrement frequency and gain. The delta status position (see Figure 1) shows an "F" or a "G". F0 (without SHIFT) toggles audio noise blanking (a new function available in SRX_400 ‘A’ receivers) which uses the automatic signal detection features of the SRX_400 to enhance audio performance, especially in aircraft or other high-noise environments.
Rev B SIGNAL/Interval routine (see above). When the signal measurement option is turned off, the signal strobe character (signal status position) is replaced by a small square. The SHIFT + SIGNAL key sequence also assigns the arrow keys to the job of closing (DOWNARROW) and opening (UPARROW) the pulse interval window, and SHIFT + TIME switches back and forth between pulse interval (in milliseconds) and pulse rate (in beats per minute) display formats.
Rev B SHIFT + CODE Digital code recognition Toggle audio noise blanking Scratchpad F0 SHIFT + F2 FTABLE 8 The FTABLE key accesses five functions. The menu is: 1)ADD 2)DELETE 3)COPY 4)PARTITION 5)SIZE Partition allows you to select one of sixteen separate tables (numbered 00 to 15) as the "active partition". Size displays a count of all frequencies currently in memory in all tables, including those which have been deleted but not restored during SCAN.
Rev B Because one or more partitions are specified for each frequency, the file is essentially a master list (all frequencies, all partitions). Once it has been sent to the receiver it may be modified by adding or deleting frequencies as described above, but when a new table is uploaded it will completely replace the existing one. If a partition is not specified for a particular frequency, partition 0 will be assigned by default.
Rev B Baud = baud rate from 110 to 19,200 Parity = odd, even, or no parity Format = number of data bits (7 or 8) and stop bits (1 or 2) Flow = XON/XOFF or other flow control protocol (version dependent) Interchar (Delay) = intercharacter delay, to allow interfacing with slow peripheral devices. Modem = provides some special modem options for cellular telephone links (version specific). The Default selection sets the default values of the configuration parameters.
Rev B feature with caution! In software versions which support coded transmitters, the CODE key also allows code set selection from the command environment and controls the code discrimination option in SCAN and SIGNAL routines. Finally, the CODE key is used to set I.D. codes for identification of records from individual receivers in automatic data logging situations F0-F3 0 -3 The top row of keys is reserved for application software and user-specified macros.
Rev B SRX_400 OPERATIONS AND EXERCISES Preface to the Examples The following exercises are designed to enhance familiarity with SRX_400 functions and operating modes . They are modeled as faithfully as possible on real applications and include a basic radio tracking session, an optimization procedure and an automatic monitoring system installation. Deleted: ¶ ¶ Example 1: Tracking You are studying caribou populations on a group of islands off the Labrador coast.
Rev B other frequencies, review the frequencies you have just entered (using the delete option), or press ESC to leave the menu of FTABLE. If you run into trouble, press the ESC key repeatedly until you are back to the main menu (frequency and gain display), and then start over. When you have created your frequency tables you will set the scan (or dwell) time. This is the amount of time the receiver will stay at each frequency in the scan table before proceeding to the next frequency.
Rev B If a signal is present, the bottom line of the display will show the pulse interval (repetition period) in milliseconds, relative signal strength and two status characters. These are an expanding "strobe" which follows the signal pulses and a letter (G or F) which gives the status of the arrow keys (control of gain or frequency). You may use the arrow keys to increment/decrement gain or frequency while the Interval routine is running.
Rev B AVAILABLE MEMORY 49746 1)INITIALIZE 2)CONTINUE The available memory belongs to the scratchpad, and the reported size will vary depending on the software version and on the current status of memory use by other programs. Initializing the scratchpad will erase current scratchpad data only. If you choose to continue, new scratchpad data will be appended to the existing record. The program will begin scanning the current active partition (active table).
Rev B ENTER FIELD COORDINATES > then enter two numbers, up to nine digits each, terminating each one with the UPARROW key. If you make an error, you can use the DOWNARROW key to delete it. After entering latitude/longitude values in the scratchpad, you are no longer interested in the transmitter you have identified, and you would rather do without the overhead of continuing to look for it. Press SHIFT F TABLE and then DOWNARROW to remove the frequency from the table.
Rev B from your computer keyboard. HOST wakes up ready to receive data. Now from the SRX_400 command environment press SHIFT F0 Depending on the particular software version you are using you will either see the Dump menu immediately or you will be given the option of selecting it. From the Dump menu, select the Pad option. The scratchpad data will appear in HOST's dump window on your computer screen. When all the data has been transferred, HOST will ask you for a file name.
Rev B subject to similar constraints! Thus the first line of defense against noise is to reduce the receiver gain. Some forms of noise are naturally "bursty", like mobile voiceband messages or satellite transmissions. Here the best remedy is for the receiver to attempt to reject signals with inappropriate time "signatures". This is the function of the pulse interval window (see below).
Rev B the display. Event_Log, running in frequency priority mode, only scans the auxiliary antennas when a valid signal is detected on the associated master, so the presence or absence of entries for A1, A2, A4 and A5 signify the success or failure of the program to acquire signals on M0 and M1. The test sequence consisted of 12 scan cycles with antennas attached followed by 13 cycles (shaded rows) with the antennas disconnected. 149.
Rev B (A Sample Session) This is a transcript of a real experiment. Four transmitters were used, having the following characteristics: Frequency 151.450 151.138 151.149 151.158 Period (rate) 936ms (64bpm) 622ms (96bpm) 973ms 1106ms Repetition Code Interval N.A. N.A. 2 pulses at 348ms 3 pulses at 339 ms These frequencies were installed in FTABLE partition 0, along with a "dummy" frequency, 151.666.
Rev B Here the system response is slower, and detectability of repetition coded transmitters (with their obligatory longer group size) is especially poor. What is happening is that so many noise events are being interpreted as impulses (i.e., ignored) that the local gain reduction algorithm has failed to reduce the gain sufficiently to clear away the other (non-impulsive) noise components.
Rev B after settling. Using a global noise threshold of 2, the gain settled to the desired value of 56, with the following result: 10/11/89 15:40:08 151.158*3R*109 10/11/89 15:41:09 151.158*3R*140 10/11/89 15:42:01 10/11/89 15:43:02 10/11/89 15:44:20 151.158*3R*127 10/11/89 15:45:47 151.158*3R*116 10/11/89 15:46:13 151.138*96*104 151.450*64*110 151.138*96*97 151.149*2R*188 151.450*64*92 151.138*96*91 151.149*2R*194 151.450*64*90 151.138*96*113 151.149*2R*195 151.138*94*86 151.149*2R*195 151.450*64*90 151.
Rev B to set up telephone links from the dam sites, where the density of data will be highest, and public phone lines are available. Each receiver will have its own modem and its own dedicated line and will operate in "auto-answer" mode, so that you may call it at any time from your computer and observe real-time performance, modify system parameters or download data.
Rev B APPENDIX A: RS232 Port Connector and Null Modem Cable Receiver Back Panel Connector (DE-9P) NAME Terminal or Computer Serial Port (DB-25P) PIN PIN NAME DCD 1 8 DCD RXD 2 2 TXD TXD 3 3 RXD DTR 4 20 DTR GND 5 7 GND DSR 6 6 DSR RTS 7 4 RTS CTS 8 5 CTS 29
Rev B APPENDIX B: Antenna Switch Control Port Pins 1-8 : ASP_8 current switch or 5V active high logic levels A7 (1) A6 A5 A4 A0 o o o o o (9) o o o o A1 o o A2 o o o (8) o (15) Pins 9-15 are at logic ground 30 A3
Rev B APPENDIX C: PROM Installation and Initialization The instructions described below are for reference purposes only and are not intended as a general recommendation or endorsement by the manufacturer for independent firmware installation by the user. To avoid the potential for degrading receiver performance or of inadvertent receiver damage, it is recommended that any firmware installation be performed by the manufacturer 1.
Rev B synthesizer count value recorded on the label. If the synthesizer count values do not match then perform the remainder of this procedure up to step 14 then repeat this procedure beginning at step 6. In the event that the values still do not match contact LOTEK Engineering Inc. for assistance. 12. The message ‘Set decode threshold?’ will be displayed. If the label containing the LO and IF information also contains a 2 digit threshold variable, answer yes, then enter the 2 digit number.
Rev B recorded on the label there are two possibilities for the discrepancy. The greatest possibility is that the ‘new PROM’ routine data has not been entered correctly. There is also a small possibility that there is an electrical fault in the receiver. The actual receiver frequency will differ from the selected frequency if the synthesizer count value is not correct. 19.
Rev B Appendix D: Additional Information This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.
Rev B INDEX active antenna, 16 adaptive gain control, 22, 23 Add FTABLE function, 13 antenna, 5, 6, 8, 16, 22, 25, 27 antenna switching, 6, 16, 27, 30 arrow keys in SCAN and SIGNAL functions, 12 auto-answer, 15 batteries, 5, 6, 7, 21 fast charging of, 5 memory backup, 6 baud rate, 14, 27, 28 Boundaries of pulse interval window, 11 channel frequency assignments, 13 channel number, 10, 13 code access, 15, 16 for receiver identification, 16 transmitter, 10, 15, 27 Code_Log, 12, 15, 16, 22, 27 command environm
Rev B terminal mode, 15, 28 time time and date function, 14 typographic conventions, 3 window for pulse interval, 7, 10, 11, 12, 19, 20, 22, 23 XON/XOFF, 15 36
