Platform Finder – Goniometer: CLS RXG-234

The detection range is very subjective and wholeheartedly dependent on so many factors that it is hard to provide a simple answer. We have seen, on the open ocean with 3-5’ swell, about 2-6 mile range. On land, with a tag on the ground, it has been anywhere between 1 and 5-6 mile range; however, with a flying bird we have collected messages 110 miles away. The major recommendation for increasing distance for any application is to raise the height of the antenna.  

The Goniometer will receive any message regardless of satellite availability. It is often referred to by customers as a “satellite in hand”. (All messages that are transmitted still have the chance of making it to the satellite regardless of whether or not they were received by the Goniometer.).

No, the tag is ignorant to whether or not the messages were received by the Goniometer. They will still try to transmit them to the satellites. 

The Goniometer works with any transmitter sending message respecting Argos modulations on Argos frequency bands ; it does not work with other modulations or frequencies (VHF, for example).

The little black screw in antenna is used to acquire the GPS location of where a message was received. This can become helpful if you want to track your location relative to the location where messages were received as might be the case when actively tracking tagged animals. It can also be used as reference locations of areas that you have checked when trying to recover a downed tag; however, you only see these GPS locations when reviewing the received data (exported from the Goniometer) or Going into the GPS menu. (Note: if this antenna is broken or removed/lost, it is not crucial to the functional of the Goniometer.)

Those handheld radios can work fine at determining whether or not a tag is functioning, and they can even be used to recover tags; however, speaking from direct experience it’s a bit of a nightmare (compared to the Goniometer). The Goniometer is a tool that was developed for a very specific function (to recover tags and to receive messages like a fixed station), and handheld “walkie talkies” or radios have more broad applications and are otherwise inferior.  

The Goniometer is only going to receive messages if a tag transmits a message; therefore, if your programmed tag is not transmitting any message, the Goniometer has nothing to receive. This is why you cannot recover a tag outside of the transmission duty cycle. 

The Goniometer is just like a satellite; it does not modify the message transmitted by the tag. You can download the messages that it received using the provided software, and you can extract the GPS data as well as the sensor data. You have to decode the message just as you would if you downloaded your message through ArgosWeb (check with the manufacturer should you have any decoding issues).

If latitude and longitude are directly accessible in the message (not FastLoc) the Goniometer can be configured to directly display it on the screen and calculate/indicate exact direction and distance.

This is covered in detail in the operator’s manual; please refer to the manual for a detailed explanation. 

If your tag has a GPS that you want the Goniometer to receive and decode please check with the manufacturer to see if they have provided CLS with the decoding scheme for this tag. This is the only way that we can help you to configure and display the GPS data from your tag on the Goniometer.

It only works with the Argos transmissions.

The display is only available on the Goniometer itself. You would use a laptop to download the data (with message content) recorded by the Goniometer, to (pre)program IDs to the Goniometer, or to stream data live from the Goniometer. The Goniometer’s display, currently, is not available on another screen/monitor/software.

All received data from IDs that are listed in the ‘favorite platform’ screen is then stored on the Goniometer (up to 200,000 messages in total). It does not matter which tag you are recovering as long as the ID is stored in the ‘favorite platform’ screen. In regards to how you access that data, please refer to the manual for a detailed explanation. If you want to  record everything regardless of the ID being one of your platform , you can active the AlltoFavorties option in Setup 2/2 screen (with a limitation of 64 Favorites ID automatically added).

If the Argos ID is stored in the ‘favorite platform’ screen, the message will be received and stored (if you are within range). 

You should wait for at least three received messages before moving in the provided direction. Compass direction is indicated after the 1 message reception after the ID was added to Favorite.

You would have to test the tag with the Goniometer prior to deployment at various ranges noting the signal strength and where it shows on the distance bar. Any kind of obstacle between you and the tag will impact the signal strength so it not a really precise indication except at sea without obstacle.

The Goniometer will receive any messages transmitted by a tag as long as it is within range. It does not matter whether or not the tag is still on an animal; therefore, you can actively track animals that are carrying tags in addition to recovering the tags once they have fallen (or popped) of the animal.

As long as the tag is transmitting and you are within range it does not matter; however, it does matter if the messages are not being transmitted due to some environmental circumstance. For example, if a tag is completely buried in the sand, the message may not penetrate far enough to be received. You could test various environmental situations prior to deployment.  

The timer is simply an estimator of when the next message should be received. If there are no issues with receiving the messages, the timer should be a mirror of your repetition rate even if it changes over time. You don’t need to know it beforehand, and you do not need to program that information into the Goniometer. Speaking from personal experience, when recovering a tag it does help to know if your tag is transmitting once every 45 second, 90 seconds, or at a different rate.

Yes; the payload content is exactly as sent by the tag. CLS Group can helps you decoding this content if the manufacturer provide the formatting of the message.

The antenna point is your reference point; it is the “North” on the Goniometer’s display compass.

In situations where grounding is caused by water immersion or being hidden by metallic structures the signal would not be received; however, if the antenna is detuned and the transmission power is lower than expected it is hard to say. In some cases you can still receive those messages from the same distance as you otherwise would if the transmission power was normal (personal experience) and in some cases not at all. Of course, if the Argos satellites receive ANY messages from the tag then you would receive those on the Goniometer. That is, if you are still getting messages coming through but just not many then you would likely use the Goniometer to be able to recover those tags.

We recommend that you hold it by the provided metal support.

There is no impact if those transmitters are not close to the 401Mhz, the Goniometer is only listening 80kHz around the selected Argos frequency.

There is almost no impact. If all of the tagged animals’ IDs are declared favorite in the Goniometer then it will store all those messages on board (exept if 2 tags are transmitting at the exact same time (goniometer will miss one). For recovery function, it will only focus on the signal from the selected tag ID.

Yes, it is possible to use it from an aircraft. As you increase the height of the antenna, generally speaking, you also increase the range. Therefore, if you are in an aircraft tracking a marine animal your range would be greatly increased compared to being in a boat on the water. Radio frequencies do not travel well over water thus you will have a reduced range in a boat (relative to in an aircraft).

We recommend mounting the antenna as high as possible either fixed on the vessel or using the provided mount with a rigid pole. This is why the antenna cable length may seem long (for those not working with marine species).

No, you don’t need to “receive multiple signals from various directions” because the AXG antenna is designed to sens with only 1 reception were the signal is coming from (no needs of triangulation) . But we advise you to wait for the first three messages to be received before attempting to recover the tag; however, thereafter you can follow the direction provided from each transmission.

Everything is IP66 rated which translates to “dust tight and protected against heavy seas or powerful jets of water” so just don’t immerse it and you’ll be okay. We recommend to rinse it in fresh water once you are done and promptly dry it off. If you have canned air or similar rinse and spray out the connectors and if possible invert it to dry (dishwashing rack works well at home, but you could probably just lean it against something in the lab, too).

The AXG Antenna in Gonio mode has a better sensitivity than the small black antenna in direct reception mode. For effects on transmission propagation, please consult Recommendations for using the RXG234 goniometer

The Goniometer will receive any and all messages transmitted by a tag as its primary function is tag recovery. Then you can download the data recorded and decode the content of the message (ie: containing behavior info)  if the manufacturer provides the description.

That is correct. When you connect the Goniometer to a computer it is only for programming the Goniometer, recovering data it has received, or live streaming the data that is being received. You can not use it in recovery mode screen at the same time it’s connected. But you can still get the direction ifnfo from the stream coming into the log_XX.txt file.

The Hyperterminal is used for debugging or advanced usage by CLS Group . for Realtime parsing, You can use the log.txt file that is continuously feed  when USB is connected.

The unit is automatically powered by USB when you connect it. You can output the live stream of messages received as they are automatically write into the log_XX.txt file once you connected to USB and started the software correctly. Description of fields is in the last chapter of the User manual.