1. David C. Leader Vice President HydroLynx Systems, Inc.
8/8/2018 7:39 AM
Tips and tricks to simplify your flood warning system upgrade to the ALERT2 protocol
David C. Leader
Vice President
HydroLynx Systems, Inc.
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. ALERT2 Advantages Data rate increase from 300 to 4800 baud
Data error detection and correction
Data collision avoidance using TDMA
Data resolution increase from
Data calibration in engineering units
Data time stamp at transmitter using GPS
Data repeat controlled by hop limit
Data packet counter for lost packet detection
Station ID range expanded
Test mode sets flag for test data transmit

3. ALERT2 Backbone Advantages
ALERT data repeat to other agencies longer needed.
Large unmanageable ALERT1 radio network divided into smaller ALERT2 networks
ALERT2 networks have separate frequencies
No longer troubled by other agency malfunctioning transmitters that are on different frequencies.
Coordinate TDMA and repeater use with local agencies sharing frequency
Exchange data through internet
Export SHEF data to NWS
Import SHEF data from other ALERT users

4. ALERT2 Migration Plan ALERT2 radio frequency selection
Use same frequency as ALERT1
Submit FCC application for new frequency
ALERT2 source addresses
Choose site ID (source address) range
Assign individual station source address
ALERT2 TDMA plan
Determine station frame length
Assign station TDMA slot assignments
ALERT2 system registration
Register ALERT2 station information with SAMS or local agency

5. ALERT2 Radio Frequency Radio frequency
Best to use a new radio frequency for ALERT2
Many new frequencies are available at Mhz spacing
Repeaters can receive ALERT1 on old frequency
Transmit ALERT1 on old frequency
Transmit ALERT2 on new frequency
Mixing ALERT1 and ALERT2 on the same frequency will result in data collisions
ALERT1 data loss and errors
ALERT2 data loss but errors are rejected

6. ALERT2 Source Address Station ID numbers (source address)
10/16/2014
ALERT2 Source Address
Station ID numbers (source address)
Station ID number must be regionally unique
Sensor ID numbers now range from 0 – 254
Data collection software will translate new station ID to store data report in database
Coordinate ALERT2 station IDs regionally
Most agencies start with station IDs above and with 1000 spacing between agencies
Station ID ranges may be assigned by agency
Register station ID in NHWC ALERT2 SAMS

7. ALERT2 TDMA Plan TDMA frame length TDMA slot length TDMA slot offset
Minimum time between station transmissions
A frame length of 1 minute allows each station to transmit data every minute if needed
TDMA slot length
Number of milliseconds limit for a station transmit
Most stations have 500 millisecond slot lengths
Weather station may use 1000 millisecond slot lengths
TDMA slot offset
Start time for station transmit in milliseconds from start of frame
A station with a 5000 millisecond slot offset transmits 5 seconds after start of minute for a one minute frame

8. ALERT2 TDMA Frame Length
10/16/2014
ALERT2 TDMA Frame Length
All stations and repeaters on the same transmit frequency use the same TDMA plan
One minute frame allows
120 stations with 500 milliseconds slot lengths.
4 repeater 5000 milliseconds slot lengths every 15 seconds and 80 station 500 milliseconds slot lengths.
Two minute frame allows
240 stations with 500 milliseconds slot lengths.
8 repeater 5000 milliseconds slot lengths every 15 seconds and 160 station 500 milliseconds slot lengths.
When planning frame length, leave room for system expansion

9. ALERT2 TDMA Slot Length Minimum slot length is 500 milliseconds
10/16/2014
ALERT2 TDMA Slot Length
Minimum slot length is 500 milliseconds
Most stations can transmit all sensor data within a 500 millisecond slot length
Weather stations may need a longer 1000 millisecond slot length
Repeaters use longer slot lengths

10. TDMA Slot Offset Assignment Tips
10/16/2014
TDMA Slot Offset Assignment Tips
Start with repeater slots
Position rain only stations near start of frame
No delay for sensor samples
Position water level and weather station slots after 30 seconds
Allows time for SDI sample or sensor power on time
Position repeater slots after stations repeated

11. TDMA drift when GPS time sync lost
10/16/2014
TDMA drift when GPS time sync lost
ALERT2 encoder loses GPS lock
GPS time sync state set to drift (2)
Change to random transmit time within frame
Collisions can occur with stations that have GPS lock
Greatest chance of collision for timed reports
ALERT2 transmitter can will hold off timed transmission by one frame to reduce chance of collision
Rain gauge TBR reports do not use hold off

12. ALERT2 TDMA 1 Minute Frame
ALERT2 transmitters only
1 Minute Frame
Minimum slot length 500ms
Maximum slot length 1000ms
ms slots available
No repeater slots assigned
10/16/2014

13. ALERT2 TDMA 1 Minute Mixed
ALERT2 transmitter and repeater slots
1 Minute Frame
Repeater slot length 5000ms
Station slot length 500 or 1000ms
4 Repeater slots
80 Station slots
20 Stations repeated per repeater slot < 5 seconds
10/16/2014

14. ALERT2 Upgrade Plan Update base station software to receive ALERT2
Test software with ALERT2 receiver benchmark data
Replace ALERT1 receiver decoder with combined ALERT1/ALERT2 receiver decoder.
Serial and network connection available
Replace ALERT1 repeater with ALERT2 repeater
ALERT1 transmitters repeated as ALERT2
Upgrade remote transmitters to ALERT2
Remote transmitter data repeated and received as ALERT2
Exchange ALERT2 data through internet
Export and import SHEF data from other agencies

15. Upgrade ALERT1 receiver to ALERT2
Replace ALERT1 receiver with 5052RD-K ALERT2 receiver/decoder
Add ALERT1 receiver/decoder option to collect legacy ALERT1 date during upgrade transition
Rack mount installation recommended
Desktop installation possible
Use AC power adapter
Connect to battery backup power system
Stand alone battery with charger no longer used
Antenna splitter uses same receiver antenna for ALERT1 and ALERT2

16. ALERT1 Receiver to be replaced

17. ALERT2 Receiver/Decoder with ALERT1 receive option

18. ALERT2 Receiver/Decoder/Repeater with ALERT2 transmit option

19. 5052RD-K ALERT2 Receiver/Decoder
ALERT1 and ALERT2
ALERT1 Transmitter
AC Power
Polyphaser
ALERT1 Receiver
Battery Backup
Antenna Splitter
Battery with charger
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder

20. Antenna Splitter and Filters
Install powered preamp after polyphaser
Increases received signal to offset splitter and filter insertion losses
Install antenna splitter after preamp
Antenna splitters have small insertion loss
Install cavity or crystal filters after splitter
Separate filters required for ALERT1 and ALERT2 receiver frequencies
Crystal filters have the best performance as filters
Very compact size and inline installation
7dB insertion loss requires preamp for signal boost
8 week delivery so order in advance

21. ALERT2 Receiver Splitter and Filters
Receiver Antenna
ALERT1 Receive
ALERT2 Receive
Splitter
PreAmp
AC Power Supply

22. Antenna Splitter and Filters
ALERT1
ALERT1 and ALERT2
ALERT1 Transmitter
AC Power
Polyphaser
ALERT1 Receiver
Battery Backup
Antenna Splitter
Battery with charger
Crystal Filter
Crystal Filter
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder

23. Program ALERT2 Receiver/Decoder
Set network IP address, netmask, gateway
Set private time server if no internet connection
Set client IP addresses to forward data packets
Change login password
Change SSH port

24. Make receiver network connections
Connect network cables to ALERT1 and ALERT2 network ports
ALERT2 receiver time sync through network
Base station computers can make IP connections to receiver for data collection
Network connection types
Listen on TCP port for connections from multiple base station servers
Port 4200 to stream ALERT2 ASCII
Port 4201 to stream ALERT2 Binary
Make a connection to a client base station server
Define clients in /etc/default/alert2client

25. ALERT2 Receiver Network Output
ALERT1 and ALERT2
ALERT1 Transmitter X
ALERT Base Station
Battery Backup
Polyphaser
ALERT1 Receiver
ALERT1 Decoder
Audio
Serial
AC Power
Antenna Splitter
Battery with charger
Crystal Filter
Crystal Filter
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
Network

26. ALERT2 Receiver Network Output

27. Make receiver serial connections
Connect serial cables to ALERT1 and ALERT2 serial ports
Serial cable to portserver
Base station computers can make IP connections to portserver for data collection
Network connection required for ALERT2 receiver for time sync

28. ALERT2 Receiver Serial Output
ALERT1 and ALERT2
ALERT1 Transmitter X
ALERT Base Station
Battery Backup
Polyphaser
ALERT1 Receiver
ALERT1 Decoder
Audio
Serial
AC Power
Antenna Splitter
Battery with charger
Crystal Filter
Crystal Filter
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
Serial PortServer
Network
Serial
Network time sync

29. Multiple Receiver Network
Use multiple receivers instead of repeaters
Eliminates radio traffic from receiver to base station
Receive ALERT1 and ALERT2
Stream received data through network to base station
Base station connects to multiple receivers

30. Multiple ALERT2 receivers
ALERT1 Transmitter
ALERT2 Transmitter
ALERT2
ALERT1 Transmitter
ALERT1
ALERT2
ALERT2 Transmitter
Antenna Splitter
ALERT2 Base Station
ALERT1 Transmitter
ALERT1
Crystal Filter
Crystal Filter
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
ALERT2
Network
ALERT2 Transmitter
Antenna Splitter
Network
Antenna Splitter
Crystal Filter
Crystal Filter
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
Crystal Filter
Crystal Filter
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
Network
Network

31. Lessons learned from installations
Check type and gender of antenna cable connectors
Polyphasers, splitters, crystal filters connect to N male cable connector
ALERT2 receiver connects to a BNC male connector
Connecting cable from polyphaser to splitter
Check length of cable required
Remove existing polyphaser from ALERT1 receiver?
Preamp increase in signal level for ALERT1 may require a higher squelch level in radio receiver
-104 dB instead of -113 dB

32. ALERT2 Rack Repeater with Rain Gauge Input

33. ALERT2 NEMA Repeater

34. ALERT2 CAN Repeater

35. ALERT2 Repeater Upgrade Phases
Phase 1 converts ALERT1 repeaters into ALERT2 concentrators
Receive ALERT1, transmit ALERT2
Single or dual antenna installations
Dual antenna recommended
Phase 2 converts ALERT2 concentrators into ALERT2 repeaters
Receive ALERT1 and ALERT2, transmit ALERT2
Antenna splitter and filter use same receive antenna for ALERT1 and ALERT2
Recommendation: Skip Phase 1, deploy Phase 2

36. Phase 1 converts ALERT1 repeaters into ALERT2 concentrators
ALERT1 Transmitter
ALERT2
ALERT2 Base Station
ALERT2 Transmitter
ALERT1 Receive
ALERT2 Transmit
ALERT2 Concentrator
ALERT1
Network
ALERT2
Antenna Splitter
ALERT1
ALERT1 Transmitter
Crystal Filter
Crystal Filter
ALERT1 Transmitter
ALERT1 Receive
ALERT2 Transmit
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
ALERT2 Concentrator
Network

37. Phase 2 converts ALERT2 concentrators into ALERT2 repeaters
ALERT1 Transmitter
ALERT2
ALERT2
ALERT2 Receive
ALERT2 Base Station
ALERT2 Transmitter
ALERT1 Receive
ALERT2 Transmit
ALERT2 Transmitter
ALERT2 Repeater
ALERT1
Network
ALERT2
Antenna Splitter
ALERT1
ALERT1 Transmitter
Crystal Filter
Crystal Filter
ALERT1 Transmitter
ALERT2
ALERT2 Receive
ALERT1 Receive
ALERT2 Transmit
ALERT2 Receiver Decoder
ALERT1 Receiver Decoder
ALERT2 Repeater
ALERT2 Transmitter
Network

38. ALERT2 Repeater Splitter and Filters AC Power
Receiver Antenna
ALERT1 Receive
ALERT2 Receive
Splitter
PreAmp
AC Power Supply

39. ALERT2 Repeater Splitter and Filters Solar Power
ALERT1 Receive
Repeater Antenna
ALERT2 Receive
Splitter
PreAmp
Battery

40. ALERT2 Repeater Upgrade Single Antenna
OLD: ALERT1 receive, ALERT1 transmit, 1 antenna, 1 radio
ALERT1 Antenna
ALERT1 Receive
ALERT1 Modem
50386 Repeater
ALERT1 RX/TX Radio
ALERT1 Transmit
Polyphaser
UPGRADE: ALERT1, ALERT2 receive, ALERT1, ALERT2 transmit, 1 antenna, 2 radios
ALERT1,2Antenna
ALERT1 RX Radio
ALERT1 Modem
ALERT2 RX/TX Radio
ALERT2 Demod
ALERT2 Decoder
50386 Repeater
Antenna Splitter
Polyphaser
ALERT1 Transmit
GPS Antenna
Polyphaser
ALERT2 Transmit
ALERT2 Encoder

41. ALERT2 Repeater Upgrade Dual Antenna
OLD: ALERT1 receive, ALERT1 transmit, 2 antennas, 2 radios
ALERT1 Receive Antenna
ALERT1 RX Radio
ALERT1 Modem
50386 Repeater
Polyphaser
ALERT1 Transmit Antenna
ALERT1 TX Radio
ALERT1 Transmit
Polyphaser
UPGRADE: ALERT1,2 receive with splitter, crystal filters, ALERT1, ALERT2 transmit, 2 antennas, 3 radios
ALERT1,2 Receive Antenna
Crystal Filter
ALERT1 RX Radio
ALERT1 Modem
Antenna Splitter
Polyphaser
Crystal Filter
ALERT2 RX Radio
ALERT2 Demod
ALERT2 Decoder
50386 Repeater
ALERT2 Transmit Antenna
Polyphaser
ALERT1,2 TX Radio
ALERT1 Transmit
GPS Antenna
Polyphaser
ALERT2 Transmit
ALERT2 Encoder

42. ALERT2 Repeater Desired Features
ALERT2 repeater supports ALERT1 and ALERT2 receive pass/block
User interface supports ALERT1 and ALERT2 pass/block list download through standard interface.
ALERT2 repeater will not transmit past its TDMA slot length.
Overflow packets are buffered then transmitted on the next frame (1 to 2 minutes); first in first out.

43. ALERT2 Transmitter Upgrades
ALERT2 transmitter upgrade kits include:
ALERT2 encoder PCB
Mounting hardware
Power harness and programming cable
GPS antenna
Mounting bracket, polyphaser, cables, strain relief, ties
SMA antenna bulkhead connector and internal harness
Maxon radio hardware
ALERT2 radio harness and
Firmware update

44. ALERT2 Transmitter Site Upgrade Recommendations
Solar Panels
Rain and level stations
5 Watt solar panel
Weather or wireless link stations
10 Watt solar panel
Battery
New 22 Amp-hr gel cell battery

45. ALERT2 Transmitter New Features
10/16/2014
ALERT2 Transmitter New Features
ALERT2 station ID is unique
Sensor IDs are from 0 to 254.
ALERT2 report types
GSR, TBR, MSR, MMR, Concentrator
ALERT2 sensor calibration
Transmit finished and data with decimal point
Trim analog data values outside of range
Transmitter time sync with ALERT2 GPS
Transmit GPS time status as sensor data
Test mode transmit ALERT2 test flag
Base station software flags test data
Timed transmit holdoff on GPS time drift
Holdoff timed transmit for one frame length

46. ALERT2 Sensor ID ALERT2 station ID is unique Sensor ID ranges
Sensor IDs are from 0 to 254
ALERT2 uses the station ID and sensor ID together to identify a sensor data value
Sensor ID ranges
0 to 8 are pre-defined
9 and 10 are defined by HydroLynx transmitters
11 to 254 can be used in your system as needed
255 is reserved for time stamp ID
Sensor
Rain gauge 1
Air temperature 2
Relative humidity 3
Barometric pressure 4
Wind speed 5
Wind direction 6
Wind peak 7
Water level 8
Battery 9
Digital status 10
GPS sync state
05/06/2014

47. ALERT2 General Sensor Report GSR
Common report type supports all sensors, data type, decimal precision
Sensor ID range: 0 – 254
Data types:
Unsigned integer
Signed integer
Floating point
Decimal precision set by transmitter
05/06/2014

48. ALERT2 Tipping Bucket Report TBR
05/06/2014
ALERT2 Tipping Bucket Report TBR
The tipping bucket report compresses several rain gauge tip reports into one packet.
Sensor ID is usually 0
Timing of rain gauge tips stored to nearest second.
Base station software will file each rain gauge tip at the time it occurred.
Data receive delays due to TDMA do not effect rainfall data analysis.
Recommend transmitter report use:
General Sensor Report for rain gauge timed reports
Tipping Bucket Report for rain gauge tip events

49. ALERT2 Multi-Sensor Report MSR
MSR compresses sensor data in an efficient packet
An MSR containing 8 sensor readings uses 12 bytes
The equivalent GSR for eight sensors uses 36 bytes
MSR limitations
English units for sensors are pre-defined
Wind speed and battery resolution are limited
Water level range limit is to feet ID
Sensor
Bytes
Format
Resolution
Units 1
Air temperature 2
Signed
0.1
deg F
Relative humidity
Unsigned % 3
Barometric pressure mb 4
Wind speed
mph 5
Wind direction
deg 6
Wind peak 7
Water level
0.01 ft 8
Battery V

50. ALERT2 Multi-Sensor Report MMR
MMR compresses sensor data in an efficient packet
An MMR containing 8 sensor readings uses 12 bytes
The equivalent GSR for eight sensors uses 36 bytes
MMR limitations
Metric units for sensors are pre-defined
Wind speed and battery resolution are limited
Water level range limit is to feet ID
Sensor
Bytes
Format
Resolution
Units 1
Air temperature 2
Signed
0.1
deg C
Relative humidity
Unsigned % 3
Barometric pressure mb 4
Wind speed
kph 5
Wind direction
deg 6
Wind peak 7
Water level
0.001 m 8
Battery V

51. ALERT2 Hop Limit Hop limit is number of times packet is repeated
Hop limit is set at transmitter
0 = No repeat
1 – 6 = Repeat 1 to 6 times
7 = Unlimited repeats
When a packet is repeated, the hop limit count is decremented (unless hop limit is 7)
When count reaches 0, no more repeats
Repeater hop limit
Does not affect repeat of packets received
Limits repeats of local sensor data
Limits repeats of ALERT1 data concentrator packets

52. Questions?