The weather station consists of a Rainwise MK III Weather Station and a webcam connected to a local web server.  The html web pages are located on a remote web server which provides access using domain name.  The remote html web page calls weather data images from the local web server.  There are also standalone weather displays.

Return to the Oak Ridge Weather Data Page.

CONTENTS -

Known Issues - Problems & shortcomings
Location - Where it is and what's around it
Units - How you read the numbers
Equipment - Description w/ source links
Future - Things I may still do to the station
Random Notes - Miscellanies
Conclusions - What I think of it all
Maps - More of where it is

KNOWN ISSUES -

• Wind data accuracy is compromised by nearby trees and buildings.

• The rain gauge is not heated and its data may be inaccurate during freezing weather.

• VWS occasionally allocates ordinate (time) lines for graphs in a non-linear manner.

• The VWS rain display graphic ordinate (time) lines are sometimes displayed in error.

• Windows occasionally returns a null file (0 bytes) instead of the webcam image.  Under certain lighting condition, the webcam continually changes image brightness.

LOCATION -

• Sensor assembly is at 340 ft (104 meters) AMSL,
  38º 54' 16.1" N,  77º 07' 11.0" W   (38.90447º, -77.11972º)
  Lee Heights, Arlington, Virginia, USA
  See maps below.

• At 13 feet above ground level, the sensor assembly is wind shaded to the southwest by the roof of the house whose peak is 7 feet higher than the top of the sensors.  The roof peak is about 30 feet from the sensor assembly.  There is a 40 foot tall evergreen tree located 35 feet to the northeast.  There are 50 to 75 foot tall distichous trees over 50 feet away in various directions.  The sky is open above and to the West and SSE.

• The webcam is located 36 feet WSW of the sensor assembly and faces WSW.  It provides a view of the road in front of the house.  The camera looks out of a window though a hole in a black paper mask which is used to reduce sun reflections in the window's double glazing.  The cam is always active.  At night, the image is black except for a street light on the left and occasionally a neighbor's yard light or passing car lights.

• METAR Weather Station, KDCA, at Washington National Airport is located N130.1ºE and 6.02 miles from the Oak Ridge Weather Station.  KDCA reports are used for elevation pressure offset adjustment and general weather comparison.  Precipitation at Oak Ridge is generally observed to be greater than at KDCA.
  

UNITS -

• Time:  local  Eastern Time  (EST or EDT)
  UT = EST + 5     |      UT = EDT + 4
• Temperature:  degrees Fahrenheit
• Pressure:  inches of mercury  (adjusted to sea level)
• Humidity:  relative humidity expressed in %
• Wind speed:  miles per hour
• Wind direction:  the 16 cardinal points of the compass (NESW)   &  N degrees E
• Rain:  inches
  

EQUIPMENT -

• Sensor Assembly

The Rainwise MK III Weather Station with wired rain gauge is equipped to measure:

Temperature
Humidity
Barometric pressure
Wind direction
Wind speed
Precipitation

The MK III is powered by a solar panel which charges a 6V lead acid battery for operation during sunless periods.  Weather sensors are sampled every 2 seconds and the data is stored.   Every 30 seconds the stored data is transmitted at 418.0 MHz.  The Computer Interface and the LED Displays receive the data and display it as if in real time, albeit 30 seconds late.

At this time, the rain gauge is not heated.  Freezing weather may cause delays and/or errors in precipitation readings.  The gauge uses a tipping bucket sensor.  See the Nation Weather Service's Heated Tipping Bucket Page for more information.

• Computer Hardware, Software & Web Pages

Two weather station programs were supplied by Rainwise with the MK III:

• Weather View 32, Version 6.0.0062, Rainwise WS-2000 Edition (WV32), and

• Virtual Weather Station, Version 12.07, Base Edition (VWS).

I like the configurability and appearance of the WV32 but the version supplied does not support the saving of weather data images.

The Rainwise Computer Interface consist of a radio receiver, logger / data formatter and serial port interface.  An LED on the interface normally blinks every two seconds when it outputs data to the VWS software via its serial port.  Data of about one second duration is received every thirty seconds from the sensor assembly's radio transmitter.  The LED illuminates for the full one second that data is being received.  If the interface does not receive data from the sensor assembly or if it is corrupted, the LED will not blink until valid data is received.

If the LED on your Computer Interface does not blink when the weather station is setup for proper operation, you can use a radio receiver tuned to 418.0 MHz to determine if the sensor assembly is transmitting.  Using AM, narrow band FM or SSB, you should hear a one second "fart" every thirty seconds.  Note:  You will not be able to hear the transmission using a receiver set for wide band FM, such as used for broadcast FM or TV audio.

ConquerCam is an inexpensive ($10 USD) and easy to use webcam manager.  Unfortunately, it is a major cpu hog.

The webcam is a Logitech QuickCam Express Camera.  Don't expect much from it.  At $40 USD list, it is Logitech's lowest end camera.

The weather server is a Dell Optiplex GX1, 550 MHz, 256 MB computer running Windows 98 SE.   VWS, using the Rainwise Computer Interface on serial port 2, is set to create and save weather image files once per minute.  ConquerCam saves a picture once per second from the QuickCam on a USB port.  Personal Web Server (PWS) provides the images, when requested, to the remote web server via an aDSL with a 384 Kbps upload.

The weather html pages are located on a remote web server where I park my domains.  Those remote pages get their weather and cam images from the dedicated weather server here at Oak Ridge.  The weather and cam images are only reloaded when you click Reload/Refresh. 

• Displays

The Rainwise Oracle MK III Multi-Display is a standalone radio receiver and display with LED readouts for:

Temperature:
     outside, inside**, windchill* & dew point*
Humidity:
     relative humidity & temp-humidity index*
Barometric pressure
Wind direction
Wind speed
Precipitation:  current* & accumulated*
Clock:  time and date

Minimum, maximum and average readings for most parameters are available.

*  Computed from current and/or stored readings.
** Temperature sensor in display.

FUTURE -

• Possibly increase the elevation of the sensor assembly by 10 feet to get it above the peak of the house. I'm not sure it's worth the effort since there are so many trees in the area.

• Possibly heat the rain gauge. Snow often results in errors. The snow overflows the gauge and may not finish melting for several days. If I do heat the gauge, I may have to move it so that the heat does not false the temperature sensor.

• Maybe get a better quality camera.  Or more than one.
  

RANDOM NOTES -

• Weather data on this site is for general reference only.  No liability is assumed by the use of information on this site.
• The term Weather Station is used herein to refer to the system as a whole. 
• The term sensor assembly is used to refer specifically to the outdoor, mast mounted, sensor assembly.
  

CONCLUSIONS -

Overall I'm pleased with the Rainwise Weather Station.  The equipment appears to be well built and was very easy to install.  As near as I can tell, it appears to be accurate.  

Even though my maximum Tx-Rx distance is only about 50 feet through a few walls, I have encountered occasional RF coverage problems where one of the displays shows all dashes, "--" (except the clock), .  It is likely that urban and government RF may sometimes interfere.  At 418 MHz, the sensor assembly transmits in the 406-420 MHz government band.  Distance to the Pentagon is only 4.0 miles ESE and to the CIA is only 3.5 miles NNW.  Many other gov agencies are even closer.   Moving the receiver/antenna a few inches usually restores operation.  The Computer Interface, with a Tx-Rx distance of 32 feet through one wall, appears to have reliable reception.

My primary reason for choosing the Rainwise Weather Station over its competitors was the good recommendation by a local Rainwise station owner and that it has a comprehensive display panel with large LED numbers which can be easily seen in the dark.  See Displays above.  What good is a display if you can't read the data?

I now wish that I had ordered the RF gauge for $100 more, instead of the wired rain gauge.  I'm seriously considering heating the gauge and will probably need to relocate it.

I have mixed feelings about the Rainwise Computer Interface.   It's date does not handle years and the leap year date, 29 February 2004, cause problems with the VWS software.  I had to reset the Computer Interface's date using HyperTerminal.  The VWS graphs were corrupted and  took a week to recover.  Also the 9600 baud serial interface takes many minutes to download a full data log before VWS will begin operation when started.  Rainwise should have provided for a higher data rate or used a USB interface.

Unfortunately, the third party software supplied with the Rainwise Computer Interface is the lowest level for each product.  Many features are disabled.   Upgrades range from $50 to $500 depending on what features you want enabled.   It does not appear that the base version of WV32 can be used for web pages.   Having to work around the many disabled features in the base version of VWS made configuration more difficult and limits options. 

ConquerCam,  WV32 and VWS are MAJOR cpu hogs.  Originally, they all ran on my primary workstation and caused objectionable performance problems.  I was forced to setup a dedicated weather server to handle just weather and webcams.

MAPS -

Update:  20040822
Created: 20031227