1 Before you begin

In order to connect directly to your SensorStation, you’ll need 2 USB->Ethernet Adapters (we recommend: https://tinyurl.com/yc6llze4), and an Ethernet Cable. If you have a V2 station, you’ll need a Raspberry Pi compatible USB WiFi adapter like this one https://store.celltracktech.com/products/wifi-usb-adapter-add-on-for-sensorstation-v2 if you want to connect via WiFi. If you have a V3 station or later, the WiFi is pre-installed on the board. Make sure to have these on-hand prior to receiving your SensorStation so there is no delay in setup.

3 Note on Version 3.0 and 3.2 SensorStation

As of June 2022 we have released the 3rd version of the SensorStation. V3 SensorStations differ from V2 stations in a few important ways.

  1. All come pre-equipped with a WiFi module built into the board. This means no more worrying about WiFi dongle compatibility; now it just works!
  2. There are 6 instead of 7 USB ports (one port slot was used to mount the WiFi chip mentioned above)
  3. The GPS is BACK to being surface mounted to the board- so no extra GPS board like we had for the later issued V2 boards.
  4. Enhanced security with new SSH login credentials. This is super important if you are SSH’ing into your SensorStation!

4 Note on Version 1 SensorStations vs. Version 2 SensorStations

This User Guide has been redesigned around the new (ca.2020) Version 2 SensorStation (V2) which includes an LCD display. Otherwise, Version 1 stations (ca.2019) are nearly identical to V2 stations. In cases where they differ, we have made note in the manual. If you are setting up a V1 station you may want to begin at the QuickStart Guide in Appendix II. If you find inconsistencies in this manual please email us at as we will be updating the manual regularly.

5 Join us in our Slack User Community

We now have a Slack workspace dedicated to CTT users. Topics range from station logistics to study design, and from data management to current development of novel analytic tool. Come be a part of the discussion and engage with other users as we push the boundaries of remotely sensed telemetry data! Click here to request access to our free and vibrant Slack workspace.

6 Congratulations

If you are reading this document, then you most likely have purchased one of our Internet of Wildlife (IoW) components. Whether you’re doing localized detailed studies of small mammals or songbirds, or you’re setting up SensorStations as part of the global Motus Wildlife Tracking System (motus.org), or you’re doing something in-between, we’ve got you covered, and this document is meant to help you get started quickly and painlessly. If for some reason you get stuck along the way, please don’t hesitate to reach out to us directly either via email () or through our online Help Desk here: https://celltracktech.com/support/.

7 Participating in the Motus Wildlife Tracking System

If you are setting up your SensorStation to participate in the Motus Wildlife Tracking System (motus.org), your station can still be used with CTT Nodes. In general, we recommend Motus stations to include 4 Yagi 10-element antennas pointing in the 4 cardinal directions. A fifth Omni antenna can be installed and dedicated to detecting nodes, or one of the Yagi antennas can be used for nodes while the other three are positioned at 120 degrees for full coverage. You may also add any number of 166MHz antennas by using a Software Defined Radio (SDR), such as a FunCube or RTL-SDR, via any of the USB ports on the SensorStation (SDRs are sold separately via third-party companies). A clear view of the horizon is preferred to get maximum range, so a height as high as possible is also advised. For more information on Motus, see Appendix I.

8 SensorStation Precautions

Treat your SensorStation board like you would any other motherboard, Arduino or Raspberry Pi. All electronics, no matter how robust, can be static sensitive. Take care no metal objects touch the board while it is operating, such as antenna connectors or cellular antennas, as this could cause electrical shorts that will damage the board. It is advised to wear an anti-static bracelet when handling SensorStation.

9 Setting up your CTT IoW System

CTT’s Internet of Wildlife System (IoW) is a complete radio telemetry system that consists of transmitters (radio tags), and receivers. Currently CTT produces radio transmitters that communicate on two frequencies:

9.1 CTT SensorStation

The CTT SensorStation collect data directly from tags and can collect data from a series of Nodes to more precisely locate tags within a study site. The SensorStation stores data and, with an optional cellular data plan, can also send those data directly to the CTT and Motus servers.

9.2 CTT Node

CTT Nodes are essentially mini-base stations: devices with integrated solar panels, a lithium battery, and an antenna to collect data from 434MHz tags (V2 Nodes) or either 434MHz or 2.4GHz tags (V3 Nodes), and send those data to the SensorStation. These data can then be post-processed to localize tags within a grid of nodes over user-defined time steps.

9.3 Understanding Detection Distances

The detection distance from Node to Tag varies for various reasons, including terrain, vegetation, and the behavior of the tagged animals. For instance, a bird flying overhead may be picked up over a kilometer away by a node, but one foraging in dense vegetation may only be detected from a few hundred meters. When using nodes for localization it’s important to note that the accuracy of locations of animals wearing tags can be as little as 30m, but can range widely depending on the density of Nodes. For localizing tag positions, the spacing and placement of nodes must allow for tags to be detected simultaneously by three or more nodes.

The detection distance from SensorStation to Node is also affected by terrain and vegetation, but also antenna height and type (omni-directional vs. directional). Therefore, while there is no hard and fast rule, a good starting point is to keep your farthest node within 1km of the SensorStation. The number of SensorStations needed for each system depends on the size of the study area. For instance, in a 2 KM2 plot, a SensorStation placed at the center of the plot could detect nodes across the entire study area, in most cases with only an omni-directional antenna. Because Nodes are dependent on the SensorStation to receive their data and aggregate it for analysis, it is critical to ensure each node is within the detection radius of at least one SensorStation at all times.

The detection distance from SensorStation to Tag is affected by the same factors as SensorStation to Node, but because many tags are on birds, bats and insects, the relationship between the two objects can change drastically over very short time steps. With line-of-sight, a tag on a bird has been shown to be detectable for dozens of kilometers by a SensorStation. On the other hand, birds foraging in dense vegetation may only be detectable by a station within a few kilometers. Therefore, careful consideration of station position with relation to the biological questions being asked is critical for a successful deployment.

9.4 SensorStation installation example

9.4.1 Materials

  • Compatible Test Tag
  • Nodes (each)
    • 1 x Node box
    • 1 x Antenna
    • 1 x Clamp hardware
    • 1 x ¾” EMT conduit
  • SensorStation
    • 1 x SensorStation
    • 1 x Enclosure
    • 4 x SensorStation Screws: #8-16 X ¼ phillips self tapping screws for plastic:
      https://www.mcmaster.com/99461a330
    • 1 x Power cable
    • 1 x Omni Antenna
    • 1 x Coax cable
  • Mounting hardware
    • 10’ long 1’’ EMT conduit
    • 10’ long 1 ¼’’ EMT conduit
    • 10’ long 1 ½’’ EMT conduit
    • Tripod
    • Clamp for attaching SensorStation to conduit
    • Tap screws
    • zip ties
    • coax tape
  • Optional
    • colored electrical tape for color-coding antenna wire ends

9.4.2 Mounting your Equipment

For both the SensorStation and Nodes we recommend attaching to EMT conduit. We recommend this because it is rigid and easy to set up. This is not what’s commonly referred to as Black Pipe used for water and gas lines, but the galvanized steel pipe used for running electrical wiring inside.

9.4.3 Building a mast for your SensorStation

We don’t recommend PVC because it moves in the wind, becomes brittle, and will snap over time. EMT can be painted if you would like them camouflaged.

The conduit can be attached to a tripod, mounted directly into the ground, or onto a building or other structure. The Nodes and SensorStations are then attached to the conduit. The diameter of the conduit is typically 1” for the top mast section of the SensorStation (the section to which the antennas are attached; light green in the picture below).

For every 7 feet of height the base section will increase in diameter by ¼”. For example, in the picture above, a 15 foot mast will have a 1” section (light green) inserted into a 1 ¼” (orange) and then into a 1 ½” (blue). If the conduit is inserted into the ground, the 1 ½” conduit should be inserted into a 4’ section of 2” pipe (dark green). The pipe in the ground is cut in half, the bottom flattened slightly with sledge hammer to keep soil from entering when it is driven into the ground. A block of wood can be used to pound the pipe into the ground to prevent bending the pipe. If the antenna mast is shorter, the next size up gets driven into the ground (1/ ¼”). Note that standard EMT conduit does eventually rust, however it will remain very strong for 6-10 years.

If desired, stainless conduit can be purchased, however it is much more expensive, but recommended if you are in an area that receives high winds. It is crucial to overlap each section of pipe by at least 2 feet. Self tapping screws are used to hold pipes together, but should not be used within 3-4” of the end of the pipes and/or seams. The chart below should help with what is needed for your setup per SensorStation.

Total Approx Mast Ht. EMT Needed for mast (10’) Ground Section Needed (4’) Coax Length Per Antenna
7’ 1” 1 1/4” min 10ft
15’ 1”,1 ¼” 1 ½” min 20’
23’ 1”, 1 ¼”, 1 ½” 2” min 25’
28’ 1”, 1 ¼”, 1 ½” 2”- Use full 10’ min 30’

Masts higher than 28’ not recommended with standard free-standing EMT conduit. Guy wires and/or scaffold or tripod masts are other options for higher towers.

9.4.4 Mounting Nodes

Nodes are typically attached to the top of a ¾” piece of EMT. The clamps shown below come standard with the nodes and accept ¾ or 1” conduit.

A 7/16” socket is used to tighten the clamp bolts. The EMT is typically driven into the ground approximately 2 feet. The height of the nodes can be changed depending on the project, but for best results should be consistent within a study site. We recommend 8’ for most setups, see below for pictures of the node setup in the field. If you choose an alternate mounting method, care should be taken that they are secure. If they are mounted on anything that sways greatly with the wind, the readings won’t be consistent.

Note: Nodes purchased in 2020 and beyond have a built-in GPS. Prior to 2020 you must take accurate GPS readings and record that data with the Node ID in order to run post-hoc localization analyses.

9.5 Node Placement

Setting up the CTT Nodes is typically done in a grid in your study site. It is not imperative that they are exactly in a grid, but the closer you can set them up in a grid, the more accurate positioning you will get from the tags. In sites where this is not practical, you can simply set them up where you can, 50-200m apart, and record GPS of the Node locations. Even in a grid setup, it is best practice to take GPS coordinates whether or not they differ from the layout. Nodes should be placed above surrounding vegetation (to ensure solar recharging of the internal battery) or at least 2.5 meters above the ground.

9.6 SensorStation Placement

If you are using Nodes, your SensorStation may be placed anywhere within range of the farthest node, which is typically 1km. See the next section on SensorStation Configuration and Antenna Detail for more details on this. It is recommended to place the SensorStation antennas at least 10 meters above the ground level. The higher the antennas, the better range you will get.

Theoretical setup with SensorStation (diamond) in the middle of two node grids (colored circle markers). All nodes are within 1.5km of the SensorStation (black circle)
Theoretical setup with SensorStation (diamond) in the middle of two node grids (colored circle markers). All nodes are within 1.5km of the SensorStation (black circle)

9.7 SensorStation Configuration and Antenna Detail

The standard configuration for the CTT SensorStation allows for receiving data on five 434MHz radio ports simultaneously. These can be configured to either record signals from LifeTags/PowerTags/HybridTags and ES-200 GPS loggers (hereafter “tags”), or to collect data from CTT Nodes. Tags and Nodes cannot be picked up on the same channel simultaneously, and how you configure your station depends on your study goals. The number of channels necessary on a SensorStation depends on the number of Nodes, whether you want to detect tags/transmitters and/or Nodes directly with the SensorStation, and the distance the Nodes are from the SensorStation. There is no hard limit to the number of nodes that can be detected by a single SensorStation, but it’s best to keep that number around 50 or less. Distance to the SensorStation will usually be the limiting factor for the number of nodes detectable by a single SensorStation.

Two types of antennas are commonly used with the SensorStation: Omnidirectional and Yagi. Omnidirectional antennas efficiently receive energy in a horizontal plane 360 degrees around the SensorStation. Omnidirectional antennas typically do not have as great a range as Yagis, but a benefit is the 360 degree detection, and great detection of tags and nodes that are near the station.

Note: Whereas in the past we have recommended specific polarization for omnidirectional antennas picking up Nodes vs. Tags, in our testing we have found the difference negligible and find vertical omni antennas to be much simpler and less expensive for a greater value over horizontally polarized omnis.

Yagis are directional antennas used to detect tags and nodes in a specific direction from the SensorStation. They typically have a 30-60 degree detection range that extends away from the SensorStation. For that reason typically 2-4 antennas are used, one pointed in each cardinal direction, or two pointed in opposite directions and used to make a “fence”. Yagis can also be used to pick up Nodes that are farther away from the SensorStation.

This is another 434MHz-only station with four Yagi antennas for picking up tags and a single verticle omni to pick up the 50 nodes on site. The large white rectangular antenna is a 900MHz antenna used to retrieve data from a custom ES-200 GPS logger tag.
This is another 434MHz-only station with four Yagi antennas for picking up tags and a single verticle omni to pick up the 50 nodes on site. The large white rectangular antenna is a 900MHz antenna used to retrieve data from a custom ES-200 GPS logger tag.

While there are many antennas to choose from, these are a few that we can recommend from experience:

Whatever you choose, make sure you get the proper coaxial end to connect your antenna to your SensorStation!

Here is a dual-mode station in Bermuda, where four 434MHz Yagis are in the top plane, and five 166MHz Yagis are in the bottom plane. Mounting antennas in plane this way means you don’t need to worry about stacking distances. This station is not listening for nodes, so all antennas are set to detect tags.
Here is a dual-mode station in Bermuda, where four 434MHz Yagis are in the top plane, and five 166MHz Yagis are in the bottom plane. Mounting antennas in plane this way means you don’t need to worry about stacking distances. This station is not listening for nodes, so all antennas are set to detect tags.

9.7.1 Connecting antennas to your SensorStation

To connect antennas to your SensorStation you will need coaxial cable (we recommend LMR-400 or better) with the proper ends to connect to the antenna (manufacturer specific) and your SensorStation. If connecting directly to the board, each 434MHz radio has a SMA Female port, so your coaxial will require an SMA Male connector.

If connecting to our NEMA case, your coaxial will need a Type N Male connector.

If connecting an antenna for a different frequency, such as 166MHz, you will need to attach your Software Defined Radio (SDR) to one of the USB ports and your coaxial cable to the SMA connector on the SDR. Note that any 166MHz radios will only show up in the SensorGnome section of the Web Interface (see Sensor Station Web Interface).

9.7.2 Mounting the antennas

Antennas are attached to the EMT conduit with the clamps that come with the antennas. If you have a setup that uses 4 yagis, than you will attach the yagis to a 4 or 5-way mounting “hat” you can purchase via online retailers. Once the antennas are on EMT, attach the coax and wrap the connection with coax tape. Run down the poles to where it will attach to the SensorStation. You can use zip ties to secure the coax to poles where needed.

Example of a 434MHz-only station, with four directional Yagi antennas (programmed to pick up tags), one small “horseshoe omni” (programmed to pick up the 21 nodes on site) barely visible at the very top of the antenna mast, and a little weather station broken out to the side from the top of the mast. Note the drip loop under the station box!
Example of a 434MHz-only station, with four directional Yagi antennas (programmed to pick up tags), one small “horseshoe omni” (programmed to pick up the 21 nodes on site) barely visible at the very top of the antenna mast, and a little weather station broken out to the side from the top of the mast. Note the drip loop under the station box!

Make sure you have enough coax to form a drip loop for each connection.

9.7.3 Adding an optional LTE extender

If you are using our on-board LTE modem for sending data to the cloud and to Motus, and you are finding you have a weak signal at your station site, you can add an optional cellular antenna to increase the range of your station transmission to the cell network. CTT does not sell cell booster antennas, but many are available on Amazon.com. Here is one example, but note that we have not tested this specific device; it’s simply to provide some idea of what might work: https://www.amazon.com/Directional-Universal-Cellphone-Amplifier-Signalbooster/dp/B089VXJV14/ref=sr_1_3?crid=L0H9JNP4DRQF&dib=eyJ2IjoiMSJ9.DwK2pym6t2RcsY6MY5SFAx_HO7CFELHCiEedhErb9Ib08Fv5Z512JpCcNzW5TUtQoA8dZItS8yOJAajf3bikFw.te4gjK0B-7qty7WuY-_NLxslPGjxqqpMRtLonWDJQOI&dib_tag=se&keywords=LTE+yagi+booster&qid=1704994609&sprefix=lte+yagi+boos%2Caps%2C133&sr=8-3

Typically, these cell booster antennas have an SMA male connector that needs to somehow attach to the SensorStation board to communicate with the modem. We have provided a SMA port on the board near the LTE modem, labeled J7. That port is not activated without first jumping the U.FL port on the modem labeled main, to the U.FL port labeled J6 on the SensorStation board. In doing so, you will activate the J7 SMA port on the board which will allow you to attach the SMA connector on the cell booster antenna to said port (see fig below).

Alternatively, you could attach a U.FL to SMA adapter (see fig below) directly to the Main port on the modem, and connect the SMA connector on the booster cable directly to the adapter, bypassing the need to jump to the board and not using the SMA port on the board itself. This option might be preferred if you use a U.FL to SMA bulkhead, which you can mount to the side or bottom of your case, allowing you to create a weatherproof access point to connect an external antenna to the outside of your SensorStation case.

U.FL jumper cable
U.FL jumper cable
U.FL to SMA adapter cable
U.FL to SMA adapter cable
LTE modem with ports identified. Note that in this image the standard patch antenna that ships with the SensorStation is currently connected to the main port on the modem.
LTE modem with ports identified. Note that in this image the standard patch antenna that ships with the SensorStation is currently connected to the main port on the modem.
  • Pink circle: Main U.FL port on LTE modem (currently occupied)
  • Blue rectangle: J6 U.FL port on board
  • Red square: J7 SMA port on board