Frequently Asked Questions � WeatherLink

Frequently Asked Questions — WeatherLink WEATHERLINK Do I need to have a dedicated computer? No. The weather station and WeatherLink hardware will operate properly whether your WeatherLink software is running or not. What are the computer requirements for the WeatherLink for Windows? The computer must be running Windows 95/98/NT/ME/XP or 2000 with at least 5-MB free hard disk space. You will also need 4 MB RAM and one free serial port. A mouse is recommended. Do I have to leave my computer on at all times to record data? No. The WeatherLink datalogger will archive data until you are ready to turn your PC on and download the data to your hard drive. How far can I extend the datalogger cable? The maximum distance between the datalogger and the computer is 50 feet. If you need to go further then 50 feet, then you could purchase our Short-Range Modem Pair (# 7875). With the Short-Range Modem Pair, you can transmit up to four miles over 22-gauge cable or seven miles over 19-gauge cable (not available with Vantage Pro systems). How much data can the WeatherLink datalogger store? The number of days the archive can store is dependent on the archive interval you have set. With the Weather Wizard II-S, Weather Wizard III, Weather Monitor II, and Perception II, for every archive interval minute there is a day’s worth of space available. For example: an archive interval of 5 minutes will give you 5 days of storage; an archive interval of 30 minutes will give you 30 days of storage; and so on. With GroWeather, Energy EnviroMonitor and Health EnviroMonitor, each archive interval minute will equal 16 hours of storage space. With Vantage Pro systems, each archive interval minute will equal 1.5 days of storage (e.g. 10 minutes = 15 days). What happens to the data if the archive fills up? The oldest records will be lost as new records are added. How do I clear the archive memory after download? From the main menu select “Setup.” From the setup menu select “Station Config”. In the Download Options select the box that says “Clear Archive Memory after Download,” then select “OK.” In the PC software it said, "downloading "#" records", and appeared to download, yet I can't see any new data. Check the time and date manually at the weather station display console. It is likely that your time and date are off and you have been recording data stamped with the wrong date. The software only writes data to the database that has a time and date after the last record in the database. How do I backup data to a disk with WeatherLink for windows? Put a floppy disk in the drive. In Windows select “Start.” From the Start Menu select “Programs.” From the Program Menu select “ Windows Explorer.” In Windows Explorer open the folder labeled “Weatherlink54.” When you open Weatherlink54, in the window on the right side of Windows Explorer you will see a folder with your weather station’s name. With your mouse “drag” that folder to the A: drive and “drop” it in. Or you can open your weather station folder and “drag” just the data files in it and “drop” those files in the A: drive. The data files have the following format: yyyy-mm.w1k, where yyyy is the year and mm is the month. 01/01/05 Can I add data to my database or edit data that is already there? You cannot add data to your database. You can, however, edit the data that is already there using the edit utility in the WeatherLink software. How do I import WeatherLink data into Excel? The following is step by step instructions for importing Davis WeatherLink data into Excel. 1. Create a .TXT file using the WeatherLink software. See the procedure “Export Records” in the WeatherLink User’s Manual. 2. In Excel, from the File menu, choose "open" to open your .TXT as a text file. 3. This brings up the "Import Wizard" in which you can specify how Excel should parse the text file. There will be 3 dialog boxes of options. 4. In the first dialog, specify that the file is a delimited file. Press the "Next" button to go to the next dialog. 5. In the second dialog, select tab as the delimiting character. Press the "Next" button to go to the next dialog. 6. In the third dialog, you will see a preview of the parsed fields. In order for the date to be parsed correctly, you may need to select the first column from the preview scroller, then select the correct date format in the upper right hand part of the dialog. Press "finished" when you are done with the third dialog. 7. Save the document as an Excel worksheet. Sometimes in the database my wind direction data is only dashes. If there is no wind speed at all during the archive interval, the software will not record a wind direction. When I view the bulletin the barometric pressure graph is only a single dot. In order for the barometric pressure graph to display a line graph, you must download the archive immediately before entering the bulletin. After an auto clear with the bulletin running the bulletin does not clear. If you have WeatherLink for Windows version 4.02 or lower, the Bulletin does not refresh. You must manually close the Bulletin and then re-open it. Versions greater than 4.02 fixed this problem and will automatically refresh. Either download the fix from our website (www.davisnet.com) or call Technical Support at 510-732-7814. The wind chill appears higher then the outside temperature in my plots. If you have not chosen “Like Variable Same Scale” from the Plot menu, the left and right axis may be scaled differently and have the effect of placing a lower value higher on the plot. Can I get growing degree-days data with WeatherLink for Windows? With the WeatherLink software degree-day-reporting feature, you can track the development of crops and/or pests. Our software can calculate degree-days using the average temperatures or by using the high/low method for calculating degree-days. My sunrise/sunset times are really off from February 18th to March 20th, then they are all right again. This happens on 486 SX PC’s or older. These PCs have no floating-point processor or math co-processor. On February 18th it cannot calculate the sunrise/sunset times. On March 20th, which is the Vernal Equinox, WeatherLink zeros everything out and the problem disappears. Sometimes I see my wind speed jump to an extremely high number, like 126 mph. This occurs most often when it’s raining. When this occurs, the first thing you should do is unplug the eight-foot WeatherLink cable from the serial port adapter at your PC or Macintosh. As you do this observe the wind speed. The wind speed should imme01/01/05 diately return to normal. If it does, the erroneous high wind speed was caused by a faulty or bad ground in the PC or at the outlet your PC is plugged into. Consult your local electrical contractor or PC specialist. What is the purpose of the link isolator? The link isolator provides upgraded protection against electrical disturbances caused by ground offsets or static charges by placing an optical connection between the WeatherLink datalogger and your computer. Since electrical disturbances cannot travel across the optical connection, the link isolator will help prevent lockups of the weather station console and possible damage to console, WeatherLink, and computer. The use of the link isolator is also recommended when the weather station console and the computer are not grounded or are connected to two different grounds. Link isolator is not available for Vantage Pro systems. I cannot communicate with the weather station from my PC. The following three steps will help you restore communication: 1. Place the small loopback connector into the WeatherLink PC adapter. The loopback connector is about 2½“ long and has a modular telephone plug on one end and a red rubber boot on the other. Plug the PC adapter into the 9-pin or 25-pin serial port on the PC. The serial port is a male connector on back of the PC. In the WeatherLink software, select “Setup,” then select “serial port.” In the serial port window make sure the baud rate selection matches what the datalogger baud rate is set to. Also, if you have GroWeatherlink software v1.1 make sure the correct link revision is selected (check the MFG. Code on the datalogger for revision). Select “loopback” and the software will run the loopback test. If it finds the loopback connector, the software will tell you what Com Port it is on. If it does find the loopback connector, unplug the loopback connector from the PC adapter, plug the datalogger cable in and proceed to the next step. If the test does not find the loopback, your serial port is either malfunctioning or in conflict with something. At this point you should see a PC specialist or someone to help diagnose your PC problems. 2. Remove and bypass any extra cable you are using between the datalogger and PC serial port. Now, select “test” or “connection test.” If the software tells you that the “connection is OK,” your problem is with the cable you just bypassed. If your connection is not OK, proceed to the next step. 3. Check that the weather station is passing its own self-diagnostics. These diagnostics are run on initial power up. Remove the backup battery if one is installed and unplug the AC adapter from the weather station display console. Wait for about 30 seconds, and then plug the AC power back in. You should hear three beeps. If you do not get these 3 beeps, the weather station or datalogger is faulty. Stop and call Technical Support at 510-732-7814. If you do get three beeps, select “test” or “connection test.” If the software tells you that the “connection is OK,” your problem was resolved by repowering the station. If your connection is not OK, call Technical Support at 510-732-7814. What are CRC errors? CRC stands for Cyclical Redundancy Check. It refers to data verification after a transmission. If a data packet does not pass a CRC checksum, then the data is ignored and an error is generated. The software continuously checks the data packet transmissions. See "Error Message Log" below. I am having problems communicating via modem with my WeatherLink. When attempting remote communications (via modem), there are two important things that you must do. You must use the Davis modem adapter. Its product number is 6533 (for Vantage Pro systems) or 7870 (for classic stations) and is not included with any WeatherLink. You must initialize the remote modem by powering up the weather station. If you are having problems you should proceed with the following steps: 1. Disconnect power from both the weather station and the modem. Do not forget to disconnect both the battery and AC power. 2. Re-power only the weather station and listen for three beeps. You must use the AC adapter on classic stations or the cabled Vantage Pro system. 3. Connect the weather station/WeatherLink to a PCs serial port using either the 9 or 25 pin serial port adapter. Verify that the Davis hardware is working by establishing a direct local connection. 01/01/05 4. Remove power from weather station again. 5. Attach the weather station/WeatherLink to the modem via the modem adapter. 6. Power up the modem first and the weather station last. The third beep issued from the weather station will initialize the modem with four commands (ATS0=4 E0 Q1 &W0). 7. In the serial port setup screen, change the Com Port setting to that of the PC modem, put an X in the modem box, and enter in the phone number of the modem at the weather station. 8. Also in the serial port setup screen, in the box labeled “After Connect Wait,” change the default 2 seconds to 8 to 10 seconds. 9. In your PC modem string, try adding an “ &F “ after the AT and/or try removing the “ &M “. 10. You also can try using the following modem strings: AT &F E Q V X4 S7=60 &N3 AT &F E Q V X4 S7=60 N0 S37=6 11. You should now be able to communicate with the weather station via the modem. Can you use WeatherLink in a network? The WeatherLink software does not allow you to directly control the weather station from any PC. You can, however, specify that when the PC connected directly to the weather station downloads data it writes the data to a shared network drive. Then, any PC on the network with WeatherLink installed (Extra User License Kit # 7862X for classic stations, # 6510X for Vantage Pro Extra User License Kit) can plot graph, print the data. Can I put my WeatherLink data on a website? Yes. WeatherLink 5.4 has full internet and FTP upload capabilities. Visit our website (www.davisnet.com/links) and see what other users have done. I want to write my own software that will integrate with a Davis weather station. On our website (www.davisnet.com) select "Support" and then select “Download Software." You will find a file called "The Programmers Reference Library." This file contains the protocol, addresses, command dictionary, a DLL, examples, etc. necessary to write your own code to communicate with the weather station through the WeatherLink datalogger (RS-232 interface). What requirements must the Mac have to use WeatherLink? For WeatherLink version 5.1: Mac OS X 10.1 or above and a USB-to-Serial port adapter. For older versions of WeatherLink: Mac OX up to 9 and one free modem port or printer port. ERROR MESSAGE LOG What are CRC errors? CRC stands for Cyclical Redundancy Check. It refers to data verification after a transmission. If a data packet does not pass a CRC checksum, then the data is ignored and an error is generated. The software continuously checks the data packet transmissions. What do the error messages that I get on screen and see in the “view log” mean? The following explains the most common error messages that are written in the log file. Generally these errors happen during unattended operation (i.e. auto-download, auto-clear, strip chart or bulletin). In addition all unsuccessful connection tests are also logged. Some of these messages will also appear on the screen. 01/01/05 Comm Error Messages The following are “Comm Error Messages” because they indicate a problem communicating with the WeatherLink. These messages can appear by themselves or as part of another message. Some messages use the “Comm Error Number” instead of the full text of message. Serial Port Error -1 This error message is used if Windows has an error with your serial port. Make sure your hardware and drives are installed correctly and try again. Computer gave up waiting for response from station. -2 This is a timeout error. For some reason, the software was expecting more data from the WeatherLink, but it did not arrive. The computer gave up waiting to transmit a command to the station. CTS low -3 The RS-232 CTS (clear to send) line can be used to tell the PC when it is OK to send data to the modem or Radio. If the CTS line is low for to long, this error will result. It can be caused by improperly setting the modem or radio or by having nothing connected to the serial port. Note: With Davis Serial Adapters this signal is always high. We did not receive an acknowledge to our last command. Please try again. -6 The PC received a wrong acknowledgement character. This is caused, on a Rev D link, by bit errors or missing bytes in the command sent to the WeatherLink, or by incorrectly selecting a Rev E link in the Serial Port Dialog Box. On a Rev E link, the command string passed its CRC, but the WeatherLink did not recognize the command. The last command sent to the station failed its CRC check -7 The PC received the wrong character signal. This error only occurs on Rev E link. It indicates that there were errors in the transmission of a command from the PC to the Weather Link. It can also result if the Rev d link is selected in error in the Serial Port Dialog Box. We are getting garbage from the station (instead of ACK) -8 The PC did not receive a recognizable character signal after sending a command: Either the response character is missing and we are reading the following data, we are not connected to a WeatherLink, or there is interference that is adding characters into the communication channel. Data received from the station failed its CRC check -9 On a Rev E link, all data received from the WeatherLink also includes a CRC code to verify the accuracy of the transmission. This error indicates a failed CRC check. Unable to make a connection. This is not officially a “Comm Error Message”. If you are using a phone modem, this error indicates that the phone call could not be completed. If you are using a radio, it indicates that the PC was unable to program the base radio to connect to the desired remote radio. Check your Connection Type Setting, the physical connection and make sure the modem initialization string is correct, or that the base radio was properly configured. You are connected to the wrong type of station: a instead of a GroWeather. This is also not officially a “Comm Error Message”. In fact the connection is perfectly good, but to the wrong station model. This is a safety feature in case you are using a serial port selection switch or have multiple phone connections available to different station models. Serious errors could result if the software tried to read or set values on a different station model than the one it is intended for. 01/01/05 Connection Test Responses The following messages appear as Connection Test Responses. Generally they correspond to one of the errors listed above, but are worded differently since the software assumes that the serial settings are being tested, whereas the above listed error messages assume that the serial port settings are correct and the error is in the WeatherLink or communication channel. If there is an error, a message appears both on screen, and is recorded in the log file. Both messages are given below if they are different. The screen version is listed first, and the log file version is listed second. The errors not listed below will generate the same messages listed above. Serial port test: This phrase is inserted into the log file before every Connection Test Error Message. Station not answering. (timeout) This corresponds to error number (-2) listed above. Station did not understand. You are possibly using the wrong link revision. Bad connection. (NAK) This corresponds to error number (-6) listed above. The command sent to the station failed its CRC check. You are probably using the wrong link revision. Bad connection. (CAN) This corresponds to error number (-7) listed above. Not connected to a station. (Command not acknowledged) This corresponds to error number (-8) listed above. The serial port is connected to a station. This program will not work with this station. This corresponds to the “You are connected to the wrong type of station” message listed above. Bulletin Window Messages The following messages are generated if there are errors while the bulletin, Strip Chart, Summary or Status Windows are active. Collectively these are all Bulletin Windows. The word “Bulletin” in any of these error messages refers to any of these windows that are open. Valid loop packet received. Whenever an error occurs in the bulletin, the next valid packet received will generate this message. This will let you know if valid packets arrived during a time period with multiple errors. Could not start bulletin will retry. (, ) This error is generated whenever there is a communication error in the command the PC uses to request Bulletin data from the WeatherLink (the “LOOP” command). See error messages listed above for the meaning of the “Comm Error Number”. The software will continually re-send the command until all the Bulletin Windows are closed. Header error in Bulletin. The first byte of the bulletin data packet must be a ‘01’. If it is not this error is generated. CRC Error detected in Bulletin. If the data packet does not pass a CRC checksum, then the data is ignored and this error is generated. 15 second timeout waiting for a sensor image. If more than 15 seconds elapse since the receipt of the last data packet, this error is generated. The software will attempt to request more data packets from the WeatherLink. 01/01/05 Strip Chart Messages The following messages are generated by the Strip Chart. Missed archive point. Will retry. If there is a communication error when the Strip Chart reads a newly created archive record, this error is generated. The software will continue to retry until the record is read correctly. You may want to verify the data was retrieved correctly in the database if this message appears more than once. Auto update turned off. Auto update turned on. These messages are generated when you turn on and off Auto Update. While there are several ways to turn Auto Update off: menu selection, scrolling the chart, or click-zooming; only selecting the menu entry will generate the “turned off” message. Download Messages These messages are generated if there is an error during a download. Archive memory is empty. Cannot download because there is no data to download. Timed out trying to download station. A timeout occurred while waiting for the 3 header bytes of a block. Counts as five errors in the retry count. Incomplete block while downloading. A timeout occurred while waiting for the 128 data bytes or 2 CRC bytes. Missed start of header while downloading. The first character of the block header must be a ‘01’. If not this error is generated. Block number error while downloading. Either the block number was transmitted incorrectly, or the block number is not the one the PC was expecting. CRC error while downloading. The data block did not pass its CRC checksum. Gave up download because of to many errors. If there are too many errors (typically greater than 20), The PC will give up the download. Error clearing archive: If you have the “Clear archive memory after download” option selected in the Station Configuration Dialog Box, and there was a communication error while performing this operation, this message is generated. Use the Set Archive Interval command to manually clear the archive. Auto Download Messages The following messages are generated by the Auto Download. Downloaded ok. The Auto Download was successful. Download of was cancelled. The Auto Download was not completed. This can happen either if there are too many errors, or the user hits the cancel button. If there are any errors, they will also appear in the log. 01/01/05 You will get one of the following error messages if you are using a phone modem and there is a modem problem when calling the remote station. OK was not received The modem initialization string was not valid for your modem. Error in command line. The phone line or dial string was not valid. See the online help file, or your modem manual for valid dialing commands. Result code error: There was a communication error while trying to read the modem’s result code after dialing the phone number. Carrier lost or not detected. The remote phone modem is not working, or a modem did not answer. No dial tone. The local phone connection is bad. Line is busy. The remote phone line is busy. No answer. The remote modem did not answer the phone call. Make sure that the modem is initialized correctly by rebooting the WeatherLink and station while the modem is turned on and connected. You should get one beep from the station right away. Another beep about ten seconds later and a third beep about 20 seconds after the second. The phone modem now should answer on the fourth ring. GROWEATHERLINK and ENERGY & HEALTH WEATHERLINKS What are the computer requirements? The computer must be running Windows 3.1/95/98/ME/NT 4.0/2000 or XP with at least 5-MB free hard disk space. You will need 4 MB RAM. You need one free serial port, a Windows compatible display and a mouse is recommended. Most printers are supported. How far can I extend the datalogger cable? The maximum distance between the datalogger and the computer is 50 feet. If you need to go further then 50 feet, then you could purchase our Short-Range Modem Pair (# 7875). With the Short-Range Modem Pair you can transmit up to four miles over 22-gauge cable or seven miles over 19-gauge cable. How much data can the datalogger store? With GroWeather, Energy EnviroMonitor and Health EnviroMonitor, each archive interval minute will equal 16 hours of storage space. What happens to the data if the archive fills up? The oldest records will begin to be lost as new records are added. How do I import data into Excel? See the instructions under "WeatherLink" above. 01/01/05 How do I back up data to a disk? Put a floppy disk in the: drive. In Windows 95 select “Start.” From the Start Menu select “Programs.” From the Program Menu select “Windows Explorer.” In Windows Explorer, open the folder labeled “Grow.” “Health,” or “Energy” (whichever applies). When you open the folder, in the window on the right side of Windows Explorer you will see a folder with your weather station’s name. With your mouse “drag” that folder to the: drive and “drop” it in. Or you can open your weather station folder and “drag” just the data files in it and “drop” those files in the A drive. The data files have the following format: yyyy-mm.xxx, where yyyy is the year, mm is the month and xxx is the file extension. If you have Windows 3.1, open the “File Manager” instead of “Windows Explorer.” When you open “File Manager,” follow the same procedure as above. Can I add data to my database or edit data that is already there? You cannot add data to your database. You can edit the data that is already there. Can you use the link in a network? The software does not allow you to directly control the weather station from any PC. You can, however, specify that when the PC connected directly to the weather station downloads data it writes the data to a shared network drive. Then, any PC on the network with the software installed (Extra User License Kit) can plot graph, print the data. I cannot communicate with the weather station from my PC. See the instructions under "WeatherLink" above. GROWEATHERLINK Can I get crop-specific evapotranspiration calculations? The GroWeatherLink software can calculate crop-specific evapotranspiration (ETo). Crop-specific K-factors allow you to calculate more accurate evapotranspiration amounts by taking into account different transpiration rates of different crops at different stages of development. Where do I get the K-factors for ETo? Any agriculture agency, university Ag extension service, or agricultural consultant should have information on specific K-factors. Can I get degree-day data on individual crops or pests? Yes, you can track degree-day totals for individual crops and pests. In the software you simply enter the name of the crop or pest, the day you want to start tracking, the base development threshold (the temperature at and below which development stops), the temperature at and above which development decreases (optional), and the number of degree-days required for this crop/pest to develop. The software will calculate the degree-days for that specific crop and the degree-days left to go. ENERGY WEATHERLINK How does the software estimate fuel usage? Based on the relationship between fuel used and degree days accumulated, a K-factor is determined. From then on, fuel usage can be estimated using the number of degree-days accumulated. What is the hot-water heater usage box for in the fuel client information window? The software has the ability to factor hot-water heater usage into its fuel estimation calculations. You may turn this box on or off by selecting the check box. You may also enter the number of gallons of hot water per day you want the software to use in making fuel estimates into the text box. 01/01/05 HEALTH WEATHERLINK What is “skin factor”? MED stands for Minimum Erythemal Dose, which is defined as the amount sunlight exposure necessary to induce a barely perceptible redness of the skin within 24 hours after sun exposure. Of course, different skin types burn at different rates, a fact, which is accounted for by the use of skin factors. MEDs may be scaled to take into account skin type. The lower the skin factor, the longer it takes the skin to burn. How do you know what your skin factor is? You can find your skin type from the following table: Skin Type I II III IV V VI Skin Factor Range 1.2 to 1.4 0.9 to 1.1 0.7 or 0.8 0.5 or 0.6 0.4 or 0.5 0.3 or 0.4 History of Sunburning &Tanning Always burns easily, never tans Always burns easily, tans minimally Burns moderately, tans gradually & uniformly Burns minimally, always tans well Rarely burns, tans profusely Never burns, deeply pigmented Warning: Be aware that skin types are only related to the sun burning effects of UV. Other UV-related health problems such as cataracts and immune-system suppression are unrelated to skin type. Therefore, changing skin factors may cause the Health EnviroMonitor to under-represent the danger of UV exposure. MODEM COMMUNICATIONS I am having problems communicating via modem with my WeatherLink. See "WeatherLink" above. SHORT RANGE MODEMS How far a distance can you communicate with short-range modems? Short- Range Modems may be used for distances up to four miles over 22-gauge cable or up to seven miles over 19-gauge cable. There is no communication using short-range modems with my Weather Wizard III or Weather Monitor II. Short-Range Modems need to be powered from the weather station datalogger. Revision D dataloggers and higher have been modified to do this. All GroWeatherLinks, Health WeatherLinks, and Energy WeatherLinks use revision D or higher dataloggers. If you intend to use Short Range Modems with the Perception, Weather Wizard II-S or III, or Weather Monitor II, you need to be sure you have a Rev. D or higher Data Logger. If the MFG. Code on the datalogger begins with L, LB, or LC, contact Davis Technical Support for information on swapping your datalogger for the latest revision. If you order WeatherLink and intend to use Short Range Modems, be sure to order part # 7862SR. There is no communication to my WeatherLink using Short-Range Modems. Be careful when connecting wires to the Short-Range Modem Pairs. Typically, if you purchase the cable from us, it comes with four wires and a bare ground wire. The color of these wires is red and black for one pair and white and black for the other. You want to make sure the XMT + and XMT - on one end goes to the 01/01/05 RCV + and RCV - on the opposite end. Since the black wires look the same it is easy to connect them to the wrong terminal (basically reverse them). If that happens an XMT will be wired to an XMT and an RCV will be wired to an RCV and there will be no communication. If you think this might have happened simply reverse the black wires at one end. WIRELESS COMMUNICATIONS The following tables summarize our wireless communication capabilities. RADIO Young Designs Spread Spectrum Radio # ZDAV2100 RF Neulink 9600 UHF Radio # 9600 FREQ. 2.4 GHz MAX DISTANCE 10 miles PROS No license required. Can be used as repeater . CONS Shorter range than UHF. Requires strict line of sight. 450-470 MHz 25 miles Longer range than Spread Spectrum. Line of sight not as strict. FCC License required. Airdesk Cellular Phone Modem # Air BCTM 9600 806-896 MHz Unlimited Range unlimited. Charge per call. Requires cellular reception. TX /RX DISTANCES WITH ANTENNA COMBINATIONS Omni To Omni Omni To Yagi Young Designs Spread Spectrum Radio # ZDAV2100 RF Neulink 9600 UHF Radio # 9600 Yagi To Yagi 1 mile 5 miles 10 miles 4.5 miles 10 miles 25 miles What are the ranges for radio communication? With Spread Spectrum the range is limited up to 10 miles. With the UHF radios the range is up to 25 miles. These ranges depend on the antenna combination you use and the conditions of the area they are being used in. The cellular has no range limitation if the areas have cellular coverage. Do I need a license for radio communications? The UHF radios require an FCC License. For the Spread-Spectrum radios and cellular modems there is no license required. Does Davis supply all equipment that is needed for wireless communication? No. Equipment must be purchased from a third party supplier. The Spread Spectrum Radio Modems can be purchased from YDI (phone # 888-233-1728). Order model # ZDAV2100. The UHF Radio Modem will need to be purchased from RF Neulink (800-233-1728). Order model # 9600 from RF Neulink. The Cellular 01/01/05 Phone Modem will need to be purchased from Airdesk (phone # 800-247-3375). Order Air BCTM 9600. All the above model numbers are the only models that have been tested by Davis and are known to work. What is the difference between a Yagi antenna and an Omni antenna? The Yagi Antenna is a directional antenna, which maximizes transmission distances. The Omni Antenna is multi-directional. Being multi-directional it is essential for use on a repeater or network base station. Is it possible to use cellular communications? Yes, with the Cellular Modem, model number Air BCTM 9600 from Airdesk. This modem is a specially designed modem with intelligent cellular interface functions built into a 3-watt cellular transceiver. Within the cellular service area, there is virtually unlimited range and no license is required. Can you use a battery to power the stations and the radio modems? Yes, you can. Our Solar Power Kit, item # 7708, with regulator and 6.5 amp hour 12-volt DC battery, item # 7711, will power the weather station and radio or cellular modems. However, when a radio modem or cellular phone modem is operated on solar power and battery, you will need to use a timer to regulate the time that the radio modems are turned on. The timer minimizes the power drain by turning the modems on and off to transmit data at user determined times. Do the antennas have to be in "line of sight"? The Spread Spectrum Antennas need to be in line of sight. The UHF Antennas should be in line of sight as much as possible but UHF Antennas line of sight is not as strict as Spread Spectrum. How high do the antennas have to be? Since the Earth’s surface is curved, antennas must be elevated above the ground if they are to communicate at a significant distance. One formula for estimating required antenna height above level ground is as follows: H = D (squared) / 2 where D = Distance in miles and H = height in feet. So if the distance was 5 miles, 5 squared = 25 which is then divided by 2 to come up with 12.5 feet. The antenna would have to be at least 12.5 feet high from level ground. Can I use wireless communications with all weather stations? Yes, you can use wireless communications with all the weather stations we manufacture. However, only the GroWeather software (and therefore the GroWeather system) has been optimized for use with wireless communications and can handle multiple weather station sites. Can I have one base station and multiple remote field stations? The GroWeather Station with the GroWeather software is the only system that will allow one base station to communicate with multiple remote field stations. 01/01/05