Station Inspection


Parts description

When to schedule inspections

Inspections should be scheduled to ensure each station operates as expected prior to any critical period for research in your region. For some collaborators, stations are primarily used for personal research projects, but it is still important to maintain station operation throughout the year to spread the benefit to other projects in the network.

Offline stations

Depending on your location, stations that need to have their data downloaded manually should be inspected three to four** ** times per year. This corresponds to spring and fall migratory periods as well as breeding and wintering periods. In northern and southern latitudes, it is common for there to be no tags present during the wintering period so it may not be as important to check stations at that time.

Networked stations

If your station is connected to the internet, data will be sent to our servers automatically. However, this won't tell you whether the station antennas have shifted direction or if the mounting structure is properly secured. For this reason, we recommend networked stations are checked one to two times per year, depending on the frequency of storms and whether the station is in a marine environment.


If an extreme whether event has been forecasted it is important to ensure any vulnerable stations are properly secured prior to the storm's arrival to minimize damage. If damage is expected, stations should also be checked after the storm has passed to fix any issues that may have occurred. This applies to both networked and offline stations.

Protect your stations from wind by keeping your antennas as low to the ground as practical. If you are in a coastal area, we do not recommend mounting antennas higher than 6 meters (20 feet). If you have a telescopic mast, you can lower antennas further than normal during the winter months if you aren't expecting to detect any tags. Also keep in mind that solar panels will act like a sail so they must be properly secured at all times.

Marine environments

Stations close to sea water will deteriorate much faster due to salt and water accelerating oxidation and galvanic corrosion. Salt fog can affect metal structures dozens of kilometers inland so the station does not have to be near the ocean to impacted.

Winterizing stations

In locations that experience higher winds, less sunlight, and sub-zero temperatures in the winter, it may important to winterize stationst during those months. With a telescopic mast you can protect your station from wind damage during the winter by lowering your antennas further than normal. You can also save on power by unplugging some or all radio devices from the receiver or even by unplugging the receiver itself.

Battery Storage

If there is significant snowfall in your region, or if the seasonal temperatures reach below -20 C (-4 F), the battery should be removed entirely and kept on a trickle charge over the winter. A trickle charger can be purchased at most hardware stores, or batteries can often be stored by a local industrial battery retailer.

If you are using a low-capacity battery (e.g.: ~50 Ah), it may get damaged during extended overcast periods in the winter so it should also be stored on a trickle charge.

In the end, usually not necessary to completely dismantle your station at any time of year, unless you are concerned about theft, or if you want to reduce the amount of environmental exposure to your equipment.

What to bring

Below are a few items we recommend you bring on each station visit:

  • Spares, spares, spares! Try to have at least two of everything you might need to replace at a station.

  • If working at heights, appropriate safety equipment (harness, vest, etc.).

  • Bolt cutters, for removing rusted bolts, etc. Very important!

  • Multi-meter: measures both voltage and resistance (to check for shorts and breaks)

  • Gloves

  • Small flat head screwdriver (for rewirign, if needed)

  • Phillips screwdriver

  • Zip ties (to secure cables and wires; close storage bin)

  • SensorGnomes only: spare SD card with software image.

Inspection Safety

When checking on a station that has been left on its own for months or longer, things will likely have shifted over time as it settles in. Corrosion can also occur, weaking supports. It's important to look for signs of weakend supports so they can be addressed before contuing with the inspection.

Snakes, wasps, and hornets are known to take refuge in and around stations so approach stations carefully when these animals are most active (especially in the fall).

What to do

By following a sequence of steps during each station visit it's harder to miss something.

Approaching the station

For safety reasons, it's important to do a proper inspection of the structure before approaching it to ensure it is being properly supported. If there are issues, they can be mitigated safely as long as the everyone is first aware of those issues.

Station structure

In most cases, stations need a structure for mounting the antennas. These take many forms, but they mostly have a central mast (can be telescopic) and a lower structure supporting that mast (typically a metal tripod).

Is the structure still standing straight? Is is properly supported? Is it showing signs of considerable corrosion where metal has been bolted together? Is the mast bent or cracked? Has the mast slid downwards or twisted since the last visit? Many of these features are most easily viewed from afar while walking towards the station.

Guy wires

If guy wires are present at this station, you must check for loose or broken lines and fix them before doing anything else. If any guy wires are frayed they should also be treated as unsafe and be replaced.

Antenna orientation

Are the antennas horizontal? If not, the mast is either bent or the structure has shifted. If you are using a tripod, it's common for them to become uneven if the feet sink into the ground.

If the antenna directions are wrong, either the mast has not been secured or one or more antenna mounts are loose. When mast is loose and there are multiple antennas, the difference between any two antenna directions should still remain the same from when the station was first installed (i.e.; the relative difference should remain the same).

Ants, Bees, Spiders & Wasps

Insect issues at Motus sites are uncommon, but on occasion they do occur. The storage and SensorGnome present attractive nuisances as a refuge for a variety of insects. The SensorGnome case is a sealed and waterproof case that should deter insects. The Action Packer is not sealed and is thus relatively easy for insects to invade. Always be cautious when opening an Action Packer. During autumn as the temperature drops the Action Packer may attract insects looking for a place to overwinter, especially some paper wasps. Ants may be attracted to the Action Packer’s environment as a safe place to incubate eggs or tend larvae and pupae. For a location that has continual insect issues leather gloves may be useful. Ant and wasp infestations may require occasional use of an insecticide.

Some examples of wasp nests include under the handles of the action packer (both at once!) as well as at the tips of antennas if they are not covered.


There is a playful aspect of bored or territorial Black Bears that on occasion causes problems with field equipment. Bears may swat at, push, move or overturn the Action Packer. The 90 pounds of battery in the bottom of the Action Packer provide some resistance, but any bear that seriously wants to move an Action Packer can do so. The batteries are sealed spiral gel cells that will not leak electrolyte, so if an Action Packer is tipped over there should not be any spilled electrolyte inside. Jostling of the Action Packer might cause severed wires, loose connections and/or other problems. Loose or broken wires may require specialized attention by someone capable of repairing electrical connections. Bears might chew on Action Packers. A possible solution to discourage repeated bear chewing is using Tabasco sauce or another product with Cayenne pepper in it on the outside of the Action Packer. If an Action Packer is repeatedly seriously moved by a bear this can be thwarted by strapping the Action Packer to the ground with earth anchors and webbing cinch straps.

Digging Mammals

Digging mammals, primarily woodchucks and foxes, may occasionally cause problems at Motus stations. When holes are dug at guy line anchors the holes can compromise the guy anchors and in a worst case situation risk tower failure in windy conditions if the hole allows a guy anchor to fail. Any and all holes should be filled in. Holes can be filled with soil or rocks. Holes dug underneath the base of a tower also need to be filled. If a serious hole is encountered at a guy anchor, obtain a cell phone picture and contact the PA Motus coordinator.

Inside the storage bin

Receivers are typically kept inside a heavy-duty storage bin which also houses the power supply and further protects the receiver from the elements.

Blown Fuse

The normal current draw of the receiver will not blow the system fuse. Blown fuses are a highly unlikely situation at Motus stations. A blown fuse is an indication of a current surge that exceeded the amperage of the fuse. The only conditions that will blow a fuse are a short circuit or a current surge resulting from a nearby lightning strike. As a first step replace the blown fuse. If it immediately blows upon replacement, then there is a short circuit in the system that must be located and repaired before the receiver can be successfully restarted. Locate the short circuit, repair it and then restart the receiver.


Rodents, from mice, to chipmunks, to squirrels, to porcupines, have gnawing teeth and are good at using them. When inspecting the Motus system check for rodent damage to the various cables leading from the Action Packer to the various external components. If rodents chewing is found on any of the cables and the SensorGnome is still operating then the chewing has probably not damaged the cables. Repair the damage to the cable by wrapping the damaged area with electrical tape to seal out moisture. Cables that are totally severed as a result of mammal chewing will need to be repaired or replaced. Contact the PA Motus coordinator if a cable needs repair or replacement.

Battery voltage

It's always good to get an idea of how much power is in the battery. A typical 12-volt battery that we use will have a voltage of 14.5 v when fully charged and can cycle to as low as 10-11 v. A low battery voltage is indicative of not enough power being stored which can be due to a damaged battery or insufficent power coming from the solar panel. Keep in mind that if you're visiting the station early in the morning, the battery voltage will likely be at a moderate level (~12 v), depending on the capacity of the battery used. During the winter months or after a long overcast period, the voltage may be even lower.

The battery voltage can be measured either by using a volt-meter or some charge controllers will have battery voltage indicators (such as the SunSaver).

Solar charge controller

The charge controller (typically Morningstar SunSaver SS-12v-10L) is a critical component essential to managing battery recharging and power supply to the receiver. Morningstar SunSavers have a good track record of reliable operation over long periods of time. If the charge controller fails the power supply to the SensorGnome will be interrupted. If the failure is due to water damage, it's possible that the batteries will discharge or a fuse will be blown.

Besides monitoring charging and battery voltage level, the indicator lights on the Morningstar SunSaver are also used to indicate error conditions by various flashing patterns other than charging heartbeat or the full battery heartbeat. If the Morningstar SunSaver ever presents unusual indicator flashing light patterns then there is a problem with the charging and power supply to the SensorGnome. In situations where the Morningstar SunSaver is presenting error codes the receiver is not likely to be functioning properly. There is probably no remedy to this other than replacing the charge controller. If you have a replacement charge controller on hand, it can be hooked up immediately and it will charge the battery if the voltage is not too low.

Water & Leaks

Receivers are stored in heavy-duty bins (typically Action Packers) to keep water out and when not modified are pretty good at keeping the interior dry. The most important part of keeping the inside dry is careful routing of the antenna and other cables into the bin when it is closed up after each inspection and data download. Routing the cables into the bin required small modifications to the bin that may allow a small amount of water into the interior of the bin. If there is water accumulating in the bottom of the bin the simplest solution is to drill a 1⁄4 inch hole in one or two of the lowest corners in the bin. If the leaking is more serious, it might be necessary to place foam weather stripping in the area where the bin was modified to route the cables into the bin.

The Receiver

If the station is not connected to the internet, not only does the data need to be downloaded, it should also be checked to make sure it is collecting data correctly. Generally, you will not need to worry about this section if your receiver is networked because all the same information should also be available online.

This section will vary widely based on the type of device being used_._ Select a tab below to view information related to your device:

When checking your station, you want to make sure your station has the following information available:

  1. GPS is working, providing a location and time.

    • Missing GPS may be: poor reception (make sure antenna has view of the sky); chewed GPS cable; broken GPS; bad connection (GPS HAT has corroded; USB GPS is not plugged in correctly).

  2. All connected radio devices are appearing on the web interface as expected

    • Missing devices indicates: loose/broken cable (most likely), USB port (or hub), or radio device is broken.

  3. Data is being collected hourly

    • Missing hourly data indicates power issues.

  4. Some data files are larger than 1 KB and contain lines which begin with "p"

    • All files 1 KB indicate data is not being collected from radios.

  5. Data folders exist for each day

    • Missing folders indicate power issues.

Please refer to the SensorGnome User Guide for more information on how to connect to and access information on these devices.

Cables and wires

Loose Connections/Shorts

While the Motus stations have been well constructed, nothing is perfect. Loose connections, disconnected wires, and/or shorts, are an infrequent gremlin that may be encountered. If something is not working look for loose connections. Solution of the problem can be as simple as identifying where the loose wire belongs and then securely reconnecting it. Sometimes, the solution is often as simple as disconnecting and then reconnecting the suspected loose connections. Shorts are harder to locate and may require additional assistance.

Having a multi-meter on hand can be very handy to trace shorts. By measuring resistance ('ohms' or 'Ω') you can identify whether two points are electrically connected (zero resistance) or not (infinite; sometimes displayed as a '1' on the far left of the screen).

Chewed or cracked insulation

The plastic insulation covering a cable or wire protects it from water ingress. Even tiny cracks can slowly cause issues by increasing electrical resistance, thereby reducing signal transmission and voltage.

To check for damage, run your hands along the length to feel for any disruption in the smooth surface. Critical locations to check are where the cables are fitted into the bin (usually via an elbow pipe joint) and wherever cables are closest to the ground on the outside of the bin.

Tag Test (optional)

If possible, we recommend you keep an activated tag test on your person at all times while visiting any station. This can provide valuable information about the stations operability without much effort. It does not necessarily measure the receptability of all antennas equally, but it's better than nothing. For a more accurate method for measuring station antenna ranges, see below:

Testing Receiver Antenna Ranges Using a Tag

Station Inspection Checklist

A prepared checklist below has been designed for stations in North America and may apply to others.

Below is a Word DOC version of the same checklist which can be modified:

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