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GroNet FAQ

GroNet FAQ –

How does it work?


Moisture monitoring probes installed in the ground are connected to a GroNet datalogger cellular modem. Readings are taken at regular intervals – generally half hourly although we can make it more frequently-  and stored in the datalogger, and transmitted every 2-3 hours via cellular network to our GroNet server.

You, the client, then log onto our website via your Internet browser and enter your personalised login and password. From there a map will appear showing your site (s) and you click on each site to bring up its most recently downloaded information.



What equipment is used?


The probes are GroNet TDT probes which measure a very large volume of soil, approximately 12 litres, and which are buried to each measure 30cm of vertical profile. Most installations will have probes buried to measure 0-30 cm, 30-60 cm and 60-90 cm below the surface.

These probes have a 3m cable, which is attached to GroNet’s proprietary datalogger cellular modem via a waterproof connector. This unit is powered by a battery which is charged from a solar panel which is also attached to the logger, and contains both a datalogger and a cellular modem and aerial.

Each site installation consists of three probes, the datalogger cell modem, and a solar panel.


What’s the difference between TDT and TDR?


Very little. TDT is just a more simple and cheaper form of the same technology. Both work on the principle of measuring the time an electromagnetic signal takes to travel down a transmission line (in our case the probe), which is only affected by the amount of moisture in the soil. TDT starts and stops in the same place and is relatively easy to measure, whereas TDR requires a short or reflection and is much harder to interpret, which is why we previously needed a high-tech piece of equipment to provide a reading using the MoisturePoint TDR system and Access Tube probe. Our TDT probes are accurate to +/- 1% volumetric soil moisture.



 How long have TDT probes been in use?


L’Eau Below have used GroPoint TDT since 2001, originally in Hawkes Bay and the Wairarapa for clients who were growing in highly marginal soils with very little margin for error and who needed more than the once or twice a week readings that were standard at that time.. This involved using probes and dataloggers, which then needed to be manually downloaded onto PC, and the use of specific software.

L’Eau Below’s clients who used this system were very happy with its accuracy, reliability, robustness, performance and ease of use at the time, so when we switched to the GroNet service they were the best option to go forward with.. In addition at that time GroPoint TDTwas used by Opus and Fulton Hogan for monitoring moisture in roadbeds, and by the Auckland Regional Council in a study on water runoff on Waiheke Island.

L’Eau Below recently re-sited some of the original GroPoint TDT probes in Hawkes Bay which involved digging them up after 13 years in the ground. They still looked brand new and as soon as they were re-installed and connected to a GroNet logger they continued to work perfectly, which was a great example of their high quality manufacture and robustness.


What do I need on site?


All that is required is that the site has cellular coverage – preferably via the Vodafone network. Even if handheld cellphone coverage is not available or patchy most sites can get coverage using either the small aerial attached to the GroNet datalogger, or with an external aerial extension approx. 2m long.



How do I access my site(s) data?


We provide you with a client login and password. You will then need to access our website

Your unique login brings up a map of your sites, where you can click on each site to bring up its graph of readings.

Different logins will have different levels of access if required. Eg. If you have a number of sites on different properties your map will show them all. If you have a manager on a particular property, his or her login will only give access to that property.


What will I see on the screen?


Once you have logged in and the map of your sites appears, you can click on any site to bring up its graph of readings. All three probes are displayed on the one graph, which as standard shows the last 7 days readings. You can then zoom in or out to view whatever period of readings you wish to see.

Current numerical readings are also displayed on the screen showing the latest reading transmitted to the server.

You also have access to a % of FWC graph which will show you how close to ‘full’ your root zone is if you have entered the FWC under ‘Settings’.



Can other info be entered onto the graph?


Yes. You can either enter rainfall and irrigation data manually so it shows on the graph, or you can attach environmental monitoring equipment to the soil moisture installation and it will be shown automatically.

You can also enter FWC lines and % of FWC onto the graph for each segment if you wish.



Can I save and print my graphs or text data?


Yes. The graphs and/or CSV text can be saved to your hard drive and/or printed direct from the website using right mouse click and the ‘print’ or ‘save’ command.

This can then be used in Excel or any other spreadsheet based software.


How much will the GroNet service cost?


GroNet will cost $900 + GST per site for a full years access. GroNet will own all equipment and install it in your property free of charge.


What are the payment options?


GroNet can be paid for annually in either a lump sum in advance ($900 + GST) or monthly via automatic payment. If paid monthly the cost will be $90 + GST per month per site for twelve months. GroNet is a twelve-month of the year accessible service.


Do I have to sign anything or commit to anything?


Because GroNet owns the equipment, you will need to sign an agreement which acknowledges this, and which gives us the right to enter your property for repair or maintenance of the equipment. You also will be responsible for any damage which occurs to the equipment while on site.

In addition, you need to commit to a 2 year minimum term for the free installation. If you cancel the service after 12 months you will be required to pay $350 + GST per site installation cost.


When will the equipment be installed?


L’Eau Below installs the majority of equipment prior to the start of the growing season. The installation process is relatively easy compared to our previous TDR access tubes, and GroNet is live as soon as it is installed and connected. You will be able to access the data as soon as your login and password are set up.