Updated 3/27/2007


Davis Vantage Pro Plus Weather Station

WeatherLink for windows version 5.7 (from Davis) Purchase of the software includes the Data Logger hardware.


Weather Station

Integrated Sensor Suite (ISS)
Vantage Pro Plus 

Feb 2004, Chandler AZ 


My Weather Station History; Soil moisture; Fertigation; Frost Prevention

Reverse Order of Chronology

Calibration 3/17/2007
I used a mercury thermometer (accurate to 0.15 F)to calibrate the Vantage Pro Weather Station.  The temperature at the time of calibration was 98 Deg F.  The calibration indicated that I was previously reading ~0.4 F too low.  I picked an overcast day to minimize solar impact.  I also used a calibrated syringe to check the rain bucket accuracy.
Console location 3/10/2007
I moved one of my consoles (RS-232 interface) closer to the irrigation control.  I'm planning on adding an Alarm Output Module to control items around the yard and I need the console closer to the irrigation controls.
Temperature Sensor 2/27/2007
I moved the extra temperature sensor back to the Weather Cam which is on my patio.  The temp sensor seems to indicate a 15 deg F temp rise for the Weather Cam.  The Weather Cam is a Dlink DCS 6620G internet camera. 
Frost Sensitivity 2/6/2007

Jan 14th and 15th brought temperatures in the 23-24 Deg F range here in Chandler Arizona.
 There are approximately 50 trees in my yard (counting palms).  The most frost sensitive being the
FicusNitida_25F (Dave's Garden)  FicusNitida_32F (McKeown)  FicusNitida_20-30F (Monrovia) FicusNitida_25F (ASU)
My own experience indicates frost damage occurs between 27F and 25F for mature Ficus Nitida trees.
Dalbergia Sissoo_10F(Dave's Garden)  Dalbergia Sissoo_30-40F (McKeown)  Dalbergia Sissoo_28F(ASU)
I have young Sissoo trees (1 to 4 years planted) all show frost damage between 28F and 25F.  The sissoo all lost leaves but recovered very quickly; after ~1 month they all had new growth on all parts of the tree.
Thevetia_30F(Dave's Garden)  Thevetia_28F (McKeown)  Thevetia_25F (ASU)
I have 8 Thevetia in my Yard and although I provided no protection (for the Thevetia)  from the 23F temperatures they showed only slight damage to the highest growth.

The trees that are not sensitive to this level of cold.
QueenPalm_20F(Sun Palms)  QueenPalm_10F(Dave's Garden) QueenPalm_25F (ASU)  QueenPalm_20F(About)
I saw no indication regarding damage to the Queen Palms.  My Co-workers claimed a different experience and after some searching (see ASU link above) I found some indication that Queen Palms may need some frost protection.
AustrailianBottle 20F (McKeown)  QueenslandBottle Tree_20F(Dave's Garden) AustrailianBottle Tree (Tolerant) (ASU)
ChineseElm 10-25F (McKeown) ChineseElm_(Hardy) (ASU) ChineseElm_-20F(Dave's Garden)
Brazilian_Pepper_Tree_20F (Dave's Garden) Braz_Pep_26F (McKeown) Braz_Pep_tolerant(ASU) Braz_Pep_20-30F (Zipcodezoo)
Even though the Brazilian Pepper data indicates that it is 2 deg F (Only!) hardier than the Ficus; the nurseries that I visited (after the Jan cold snap) had no issues with Brazilian Pepper trees while the Ficus trees were dieing.  My experience is similar; I believe the Brazilian Pepper is significantly hardier than a Ficus tree.
Shamel_Ash_20F (Monrovia)   Shamel_Ash_22F (McKeown)
Tipu_25F (McKeown) Tipu_25F (ASU)

Pindo Palm Hardy (Sun Palm Trees)
California Fan Palm_15F (Sun Palm Trees)
Canary Island Date Palm_15F (Sun Palm Trees)
Shoestring_Acacia_20F(AridZone Trees)
Oleander_20F (ASU)
Katie Ruellia 28F(McKeown)
Useful Links for plant information.
ASU_cmartin     McKeown   Dave's Garden   Sun Palm Trees   Arid Zone Trees  Monrovia
 USDA Plant Hardiness Zone Map

Frost Protection   2/5/2007
My Ficus trees are too large to cover effectively (> 20 feet ). I had prepared for this event by placing 40W light bulbs in the Frost sensitive trees in my yard. The bulbs were colored ceramic red which results in limited light but it produces warmth. The intent is to provide a small amount of warmth and possibly keep the temperature 1 or 2 degrees warmer. I have a frost alarm that signals when the temperature reaches 30 Degrees F and I enable the warming lamps. The warming lamps can be enabled remotely via the internet or telephone.

A temperature sensor is mounted in a sissoo tree near the trunk about 2 feet from the top approximately 7 feet off the ground.  This plot shows the warming lamp alone can provide up to 1-3 degrees warming.  Notice the coldest temperature occurs just after sunrise at approximately 7:30 am.

Frost Protection: 
In addition to the warming lamps; I utilize frost water. Basically, my frost sensitive plants are all on one drip line (valve) and I enable the valve when the temperature drops below 28 degrees F. The soil temperature at a 1 foot depth was 51 degrees F at this time (per my sensors) and 52 Degrees F at a 2 foot depth. This allows the water to radiate heat into the air starting approximately 20 to 30 degrees warmer than the air temperature.
This plot shows the warming lamp and frost water combination.  The sub 24 degrees are warmed to approximately 27 degrees.  The lowest temperature again occurs just after sunrise at 8 am.
Frost Protection:
The final and most aggressive frost prevention method is propane cooking stoves. I have propane cooking stoves that utilize the 16.4 oz bottles. These stoves are advertised (on the box) to last 5 hours; however my experience would indicate 4 to 4.5 hours from the bottles.
The plot above shows lamps, frost water and propane stove. Note the stove duration is less than 5 hours. This is key because the coldest point usually occurs just after sunrise.
Frost Prevention:
Another technique is a spray that helps prevent freezing damage.  There are several brand names here are some of the available products.
Cloud_Cover    Wilt_Pruf
These products seem to provide some plant protection; however; depending on the time duration of the freezing temperature.  I spoke to several nurseries in my area and they used the Cloud Cover product during the Jan 14/15 Cold snap.  The nurseries had had similar results that indicated 22 or 23 degrees F is too cold for the Cloud Cover product to be completely effective.
1/13/2007  I managed to get the Temperature station to work again.  I'm using it to measure the Frost sensitive tree temperatures in the yard to see if my Anti Frost Techniques are working..
12/26/2006 The temperature station has been behaving erratically for quite some time. I cannot purchase a replacement; I may need to begain upgrading to the Vantage Pro2.     
10/12/2006 I decided to move the attic temperature monitor into the yard.
I had hopes to monitor the webcam temperature. The unit begain to behave erratically.
9/18/2005 Weather Cam
I purchased an Internet camera a Dlink DCS 6620G .  The unit is wireless (except for the power) and I intend to make the camera viewable from the Weather Recording Page. 
6/21/2005 Calibration.  I purchased a mercury thermometer that is accurate to 0.15 Deg F.  I used the mercury thermometer to calibrate the Vantage Pro Weather Station.  The temperature at the time of calibration was 104 Deg F.  I had spent considerable time prior to the calibration comparing my readings to other sites and thermometers.  The calibration indicated that I was previously reading ~0.5 F too high.
5/14/2005   I painted Rain Bucket from black to a flat white color.
 This was in an attempt to minimize the solar "heating" caused
by the intense sun in the Phoenix desert.
Look here: http://ecatalog.campbellsci.com .
You then need to add a CS data logger like the CR210 which sells for about $610 (ouch).  I found the watermark soil moisture sensors at http://www.frostproof.com/catalog/t200s.html for a low price (lower than Davis).
1/17/2005 I decided to add a Fertigator (brand name) to my irrigation system.  The Fertigator is a system for injecting liquid fertilizer into the irrigation or drip line water.  The concept (or sales pitch) is that it is better to add a small amount of fertilizer during every watering cycle than to have big doses 2 or 3 times per year.  I will comment that this spring the Shammel Ash trees and the Australian Bottle trees looked very lush and healthy.
1/14/2005 I added three additional soil moisture sensors with temperature probes.  I used a 1 foot depth as the standard.  I implemented sensors in each "zone".  I have one in the palm tree  and shrubs "zone" which is also a tropical plant zone.  I have a sensor in the Australian bottle tree or sub-tropical zone.  I have 2 sensors in the Shammel Ash tree zone also a tropical zone; one at 1 foot depth and 2nd at ~2foot depth.  I soaked the sensors in water over night and then "planted" them just before a watering cycle.  I used a precisely sized pipe to "core out" the soil leaving a hole that was a snug fit to the sensor.  I attached a piece of PVC to the sensor and that PVC is visible above ground in the above photo.  I found that the 1 foot depth sensors are more representative of the requirements during the summer months when water is critical to plant life here in the desert.
1/1/2005  Davis instruments announced their new line of weather stations the Vantage Pro2.  The Pro2 series was incompatible with the Pro series.  This obsoletes the Vantage Pro series and Davis began a clearance sale on the station and accessories.
I "planted" the soil moisture sensor next to a tree well (Southwest side) in by back yard.  I positioned the moisture and temp sensor about 22 inches deep  about 4 inches outside the tree well.  After seeing the moisture and temp sensors operate for several hours, I began my irrigation cycle. After four hours of irrigating the tree well the soil moisture sensor indicated "submersion".  The typical rule of thumb is the water penetrates at a rate of 1ft per hour and slower in clay soils.  It seems the penetration is about half this rate.  The Davis information indicates that two irrigation cycles are required for accurate data from the moisture probe.
I added a soil moisture sensor to my installation.  The soil moisture sensor has significant "break in" period.  For example, wet for 30 min, let dry overnight, wet for 30 min, let dry all day, wet for 30 min, let dry all night, soak for 24 hours.  And then plant in a very specific manner.  I eventually added a number of soil moisture sensors; see 1/14/2005.  The unit shown here will support 4 soil moisture sensors each requiring a soil temperature probe.  I shortened the break in period significantly.  See Below.
I added a wireless repeater to my installation.  I moved the ISS weather station to a more distant location where it would be in direct sunlight most of the day.  Also, a more accurate wind speed calculation.  The actual distance from ISS to console is not that large ~70ft, however, I need to go "through" a bathroom wall with plumbing. The temp station is still ~20ft away through one wall.  The repeater is set for just the ISS station.
I added a fan-aspirated radiation shield to the Weather station today.  I discovered the sun intensity in Arizona is such that it makes acquiring accurate data difficult.  A simple delta offset causes an error on either the high or low temperature.  The fan seems to keep the max temperature ~2 degrees cooler.  I also tried adding tree wrap with Styrofoam spacers to keep the direct sun off of the unit.  The wrap and foam eventually become deteriorated by the weather.  I have now tried painting the black rain bucket a flat white color.  See 5/14/2005


I added a text only web page data.htx using weather tags.  This allowed me to generate a text only page that updates just like the graphical page.  I am now able to view current weather using my Web Enable cell phone.

3/15/2004  Overlay plots
I asked Davis if there is any way to overlay plots.  For example, inside temperature and outside temperature and generate a gif file (similar to Reception % above).  I pulled this data into Excel to generate the plot to the right.   I was told this is not possible within the Davis Station software.


Reception %

I have two wireless stations, the ISS is outside
and the Wireless Temp Station (Temp) is located in a separate room in my house. The distance between the console and the ISS is 50 ft. with the console placed on the inside of a window sill. The 50 ft. distance is line of sight through a glass window. The Wireless Temp Station is 30ft away from the console with the RF path being through 1 wall.

This plot shows the reception percentage with both wireless transmitters operating. 

I discovered that my 900MHz cordless phone effectively jams the console receiver if Im using the phone within ~10ft of the console. I made certain not to use the phone when these plots were generated.
The proximity of my 1GHz computer to the console also seemed to be integral to the problem.  The problem seemed to be the result of two interactions  1) Keep 900MHz phones ~20feet away from console and 2) Keep console about 6feet away from 1GHz computer.  These two items seem to result in good ISS reception.

The ISS is outside; ~50feet through 1 wall.  The Temp station is about ~20feet through 1 wall.

Reception %
I communicated my reception problems to Davis via several emails.  I emailed tech support several times sending gif plots and explaining my reception data.  I ran several experiments moving the transmitters around.  I've included the Davis tech response below.  After 5 emails with no traction on solving the problem, I gave up.  I guess that was the point.

I did view the two gif files and did see the difference. I simply can't explain that. You might want to recreate the experiment. It shouldn't make much difference.


The replacement ISS (Integrated Sensor Suite) board arrived (at home. See 2/18 ) today. I replaced the board in the ISS. The ISS reception immediately dropped. After 12 hours the ISS reception is averaging about 55%.
I recorded rainfall with the weather station for the first time today. A whopping 0.01 inch of rain.


I mounted the ISS onto a tripod mount in the back yard. I utilized a long mounting pole placing the Anemometer about 12feet high and the Temp, Rain, Humid, Solar and UV sensors at 7 feet.

ISS Reception %:
I noticed after about 12 hours worth of data that the ISS Reception % dropped to zero for some intervals of time.

No ISS signal:

I called the Davis Tech Support number and technician answered my call at 7am PT. After I described my problem, the tech had me repeat some of the Troubleshooting Tips. Then I was instructed to remove a cover panel. Beneath there was some electronic components and a double pin mount. The tech informed me that there should be a jumper on the pins. I looked through the hardware for the missing jumper but could find nothing. The tech informed me that the board could not be properly tested at the factory without the jumper and he would send a new board for the ISS. I then asked the tech to ship the board to my work address instead of my home address. This was where the experience turned unpleasant for me; however, the tech did eventually agree to ship the part to my work address after some unpleasant conversation.  The replacement ISS (Integrated Sensor Suite) board arrived at my home on 2/26.


I received my weather station on the 17th of Feb. I quickly unboxed the Integrated Sensor Suite (ISS) and the Console. I went through the startup procedure and I was immediately disappointed. The console could not locate the signal for the ISS. I then unboxed the Temperature Sensor Station and started the second transmitter. The console was able to find the signal from the Temp Station. I then proceeded to perform the troubleshoot tips listed in the documentation that came with the Davis stations (7 manuals not counting the mounting hardware manuals). The troubleshooting steps were ineffective in locating the ISS signals.

Order Process
I ordered a Davis Vantage Pro Plus weather station from ProVantage. I found ProVantage to be hundreds of dollars less than some of the other online retailers. It was well worth the extra email that you need to send to ProVantage to see their lowest prices. I noticed that shortly after my purchase, other online retailers began a similar process.

I choose the Davis Vantage Pro Plus for several reasons. I especially liked the Solar Radiation and UV Sensors (very useful in a desert climate). The Davis had an excellent RF range for the wireless.

Wireless range is up to 400' (120 m) outdoors, line of sight. Typical range through walls under most conditions is 75' to 150' (23 to 46 m)..

This seems to be very optimistic; see 2/29 for a reception % for a 50' range.