Kestrel 5500FW Fire Weather Pro

© Brooke Clarke 2018

Kestrel 5500FW
                  Fire Weather Pro

    Blue Tooth
    Data Port
    Probability of Ignition
    Setting Altitude
    Battery Life


I've had an interest in weather for many decades.  As part of my interest in preventing wild land fires where I live weather is a key factor in how easy it is for a fire to start.  For example most big wild land fires occur in October after a long drought and when there are winds.  That's to say when the kindling is very dry and the Probability of Ignition (PIG) and Fine Dead Fuel Moisture (FDFM) are in the danger zone.  The idea is to be able to monitor the fire weather condition at my location.

The first thing to check is the effect of a sprinkler on the fire weather.  I'm hoping that the humidity can be raised lowering the PIG.  I expect that the amount of water needed will vary with the temperature and humidity already present.

Nielsen Kellerman Inc is the parent company of Kestrel.  They started out making equipment for rowing shells.


The 5500FW is part of the Kestrel line of hand held weather instruments.  This version includes the weather vane and LiNK Bluetooth option.  The Kestrel LiNK app for my cell phone works.
UPC: 7 30650 00333 4
p/n: 0855FWLVORA


There are a few ways to operate the 5500FW.  Manually, using the LiNK Blue Tooth app or by means of the optical data port.


This option adds a vane and pivot so that the whole instrument turns so it's back faces the incoming wind.  That way the wind direction reads where the wind comes from. The impeller is very sensitive and so is the pivot bearing, but a bubble level would be good on the 1/4-20 mounting screw to get the most direction sensitivity.


The 5500FW continues to log even when the LCD has turned off.  This is controlled by the Auto Store On/Off setting.


I've discovered a couple of ways of using the meter manually.
If the Options/Exit button in the upper left is pressed there is a menu of settings you can access.
  • Bluetooth - On/Off/Connect
  • Data Port - On/Off
  • Memory Options - Clear Log/Auto Store/Store Rate/Overwrite
  • Graph Scale
  • Display - Auto Shutdown/Contrast/Backlight
  • System - Time & Date/Compass Cal/Measurements/Units/Language/Battery/Factory Restore
  • About - Version/Legal
After pressing the top center "take reading bar" then the scroll up/down arrows select the screen for each type of measurement.  When a measurement is displayed then pressing the center navigation button (<Select> opens the setting menu for that measurement. When the left or right scroll buttons are pressed different display options are shown for that measurement: Digital value -> Min/Average/Max -> Graph <Select> graph of individual Data Points

Blue Tooth

This only works when the LCD screen is on.  Once the instrument times out the Blue Tooth radio is off and so you can not connect to if from a phone.  You must press the "on" button on the 5500FW to activate the Blue Tooth radio.

Smart Phone

Using the LiNK app you can connect to an Android or iPhone and both change settings, view current readings, view log data, or export log data.  The Android version does not (25 April 2018) allow updating the 5500FW firmware, but the iPhone version does do firmware updates.

A product improvement would be to allow the smart phone running LiNK to act as a data shuttle. 
1. in field connect phone to 5500FW which I think automatically loads the log data.
2. in field disconnect from 5500FW (just walk away)
3. when in cell phone range email data to yourself or someone else
4. connect phone to desktop or laptop computer using standard USB data cable (not Kestrel cable) (when phone is not connected to 5500FW & 5500FW is still in field) and transfer log file to computer. Or maybe works if 5500FW is near desktop even though outside?  The phone app does work that way. Maybe a 10 foot range through walls/front door.

Manual for phone app -


This custom USB dongle allows connecting to a laptop or desktop WIN or Apple computer.  On order, but it's supposed to allow updating 5500FW firmware from a WIN desktop computer.  Also will allow getting data from 5500FW into computer, but it requires physically bringing 5500FW from the field to the computer.

What is Kestrel LiNK for Windows? - 2018 April 30: kestrel_link_setup_1.04.03_4.exe
Note there is a separate program for WIN to update 5500FW firmware.

Kestrel LiNK for WIN running, no dongle, no cables
after restarting the desk top computer:
Connected to dongle in a few seconds,
but still searching for cables.....
moving 5500FW from 10 ' to 3' allows software to find it.
                        LiNK for WIN running, no dongle
About screen 30 April 2018 
Kestrel LiNK for WIN running, no dongle
Bluegiga BLED112 Bluetooth® Low Energy Dongle -
BLED112 - KE-0786
K5 LiNK for Windows Bluegiga Dongle Help   (Size: 5 MB) - contains the WIN drivers.

                        Low Energy Dongle KE-0786
Bluegiga Low Energy Dongle in Devices and Printers
General: This device is working properly.
Port Settings: 9600-8-N-1-N
Driver: Bluegiga 11/15/2009, Ver: 5.1.2600.0
Bluegiga Low
                        Energy Dongle

In the above windrv folder \ dfu.inf file the date is Date = "01/28/2010"
Following the procedure in the Dongle help pdf leads to:
                      BLED112 update
My 5500FW is version 1.21 which is current as of 30 April 2018
Restarting WIN7 and bringing the 5500FW within a few feet of the dongle seems to allow connection.
Now Connected to dongle and searching for cables, but found 5500FW!
Options when Manage is clicked after selecting the device in left window.
                        dongle managed from WIN7 desktop
Clinking on Download log does that.
Now WIN7 program shows data log info
Kestrel WIN LiNK with data downloaded
Now how to find that data?
How to control 5500FW, like when using the phone app?
It appears that even when the WIN7 program is closed the dongle maintains a connection to the 5500FW preventing the phone app from connecting.
                        WIN LiNK with data downloaded

Battery Life

When the On/Off button is pressed and the screen turns off (along with the Bluetooth) the data logging continues.  In this mode a lot less power is needed than when the screen is being updated and the radio is on.

I think it was on 2018 Nov 16 that I put in a new L91 battery and today I transferred the data log (30 minute interval).  Today 2019 March 18 it took 15 to 30 minutes to (1) move the data from the 5500FW to my phone and (2) format the data into a spreadsheet in order to email it.  The data file has 5,739 lines with columns from A to Q.
The Zetex ZTS battery tester shows the battery I just removed at blinking red (i.e. dead).  Yet the data file has an entry for 2019-03-15 2:00 (am).  The next entry is for today at 10:00 am which is during the time I was downloading the data file.  So this battery worked until a few days ago.

So . .  4 months life from the LS91 AA cell.  Excellent performance.
Now I'm using the "dead" battery as a way to test some AA flashlights  . . . Back Up Emergency Lighting

2020 Sep 9 - swapped the L91 battery for a new one where time between batteries was a second or so and did not turn on the unit prior to the swap.  The idea was to retain the data.  But it turns out that the 5500FW stopped recording data on 2020 April 8 yet after installing the new battery I was able to extract the data, meaning the data storage does not depend on the AA battery.

The data spans 3/21/19 to 4/8/20, i.e. just over a year.  The recording interval was 30 minutes. 
Cases where the PIG was 50%: July 25 4:00 & 6:30 pm; May 10 5:30 to 6:00pm, October 27 12:30 to 4:00 pm.  I have never seen the PIG above 50% since I've had the 5500FW, except for the first day just after power up (see photo at top of page).

Data Port

This is an IR optical system with seperate paths for transmit and receive, similar to the one on smart electric meters or the OnSet G-Pendant.

Probability of Ignition (PIG)

See the Fire Weather paragraph on my Home Fire Protection web page.
The Univ. of Montana - Making an Impact in Wildland Fire - has done a lot of research on this issue.
It's not clear to me how the 5500FW makes the computation for Probability of Ignition or Fine Dead Fuel Moisture and how long it takes to converge.
Yesterday I powered up the 5500FW and initially it showed a PIG of 80%, but after sitting outside overnight, by noon it's displaying 10 or 20%. See Fig 9 below
Unit 10: Fuel Moisture - on line course for wildland firefighters

Setting Altitude

Going on line to get the barometric pressure from the local airport/radio station. 29.94" Hg.
On the altitude screen press return to get to settings.  The default units are " Hg so scroll down to the pressure.
By pressing and holding down the scroll left or right button you can make large charges by waiting to bigger steps.  Then use fine presses to get the actual value.  When set the altitude shows 858'.

Now go to the altitude screen and press return for settings and set the altitude to 858 feet.
I zeroed the log and will see how it does in the future after the settings. 5:30 PM 5/5/2018.


Fig 1 Caution label on box for a single L91 AA battery.
                    5500FW Fire Weather Pro

Fig 2 Comes with carry case
                    5500FW Fire Weather Pro

Fig 3 Case holds both meter & vane.
                    5500FW Fire Weather Pro
Fig 4 The battery compartment release is on the bottom.
Uses a single L91 (recommended for cold) AA battery.
Two transparent windows in battery cover are for data port.
                    5500FW Fire Weather Pro
Fig 5 Kestrel LiNK app on Google Play
                    5500FW Fire Weather Pro
Fig 6  Wrist strap is not used when vane is used.
Mounted on Tiltall tripod in forest.  I wasn't expecting to see a wind speed indication, but even at 2 MPH it reads speed AND the vane points it into the wind. Impressive.
The magnetic compass captures the direction from which the wind blows.
                      5500FW Fire Weather Pro
Fig 7
                      5500FW Fire Weather Pro
Fig 8 Kestrel LiNK app on LG G6 showing  some of the readings, scrolling needed to see them all.
                      5500FW Fire Weather Pro
Fig 9 Log showing PIG
First turn on
Kestrel 5500FW Fire Weather Pro
after a day Auto Store=On
Kestrel 5500FW Fire Weather Pro


5099689 Apparatus for determining the effective force applied by an oarsman, John H. McGinn, Nielsen Kellerman Inc, 1990-11-19 - rowing shells
5357794 Faraday effect small boat speed transducer and waterproof connection for same, Paul Nielsen, Nielsen Kellerman Inc, 1992-06-12 - rowing shells between about 0.5 and 10 m/sec.
5783753 Vane anemometer having a modular impeller assembly , Richard Kellerman, Nielsen Kellerman Inc, 1997-04-17 -
5939645 Vane anemometer having a modular impeller assembly, Richard Kellerman, 1998-06-23 - wound temp. sensor leads for thermal isolation
6257074 Vane anemometer with thermally isolated sensors, Richard Kellerman, Nielsen Kellerman Inc, 1999-05-27 - Classic wind speed & Temperature
D461421 Vane anemometer, Richard Kellerman, Alix James Kocher, Michael T. Naughton, Brad Juchno, Craig Hidalgo, Rory McDonnell, 2001-03-30 - Classic Kestrel unit
7059170 Method and apparatus for measuring relative humidity of a mixture, Richard Kellerman, Paul H. Nielsen, 2004-02-27 - better compensation for temperature
D547679 Watch, Leslie Juhng, Mathieu Turpault, Nielsen Kellerman Inc, 2006-04-24 - waterproof case
D642155 Megaphone,
Thomas Dooley, Mathieu Zastawny, 2010-12-10 - eelectronic, easy to handle in rowing shell
Electronic data device, Michael T. Naughton, Alix Anita James, Yohann L. Rigogne, 2013-07-03 - "Drop" series of weather loggers
Electronic data device ,Michael T. Naughton, Alix Anita James, Yohann L. Rigogne, 2013-07-03 - "Drop" series of weather loggers
Method and apparatus for measuring relative humidity of a mixture, Richard Kellerman, Paul H. Nielsen, 2006-06-07 - 


Home Fire Protection
Smith Indian - Fedco Fire Pump
Wallace & Tiernan FA 181 Altimeter


Univ. of Montana - Making an Impact in Wildland Fire -
Bird Precision - maker of jewel bearings (like used for anemometer assembly) - company video mentions Pyrex Glass bearings (balls?) have "very low breakaway friction", just the thing for a wind vane that is specified to start "at 2 feet per minute of air"

YouTube: Kestrel Weather Meter vs. Sling Psychrometer - U of Mont. Fire related.
YouTube: Barometric Pressure vs Station Pressure -


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