🔨Mounting Your Radio

Overview

Properly mounting your radio is an important first step to making sure your robot connects to the field and remains connected throughout a match.

Here are some initial considerations when thinking about where to mount the radio on your robot:

Consideration

Reason

The radio should be mounted against a metal tube or plate.

Heat can build up inside the radio. By mounting the radio against a metal surface, you can conduct heat away.

Do not block the visibility of the status LEDs.

These LEDs are used by field staff to diagnose connectivity problems. Without these LEDs it becomes much harder to troubleshoot why your robot may be having connection issues.

Avoid having objects within 12" of the radio (Not including the back of the radio, opposite the status LEDs).

The antennas inside the radio have a radiation pattern. Having objects pass too close the radio can alter this radiation pattern, and adversely affect how well the radio is able to communicate with the field.

The radio should not be fully enclosed by a case or mounting solution.

This traps heat in the radio and can cause the radio to overheat. When the radio is overheating the latency will increase.

It is recommended that teams mount against a metal tube/plate to act as a heatsink for the radio during extended operation.

Where To Mount Your Radio

Here are some examples of different places you can mount the VH-109 Robot Radio to your robot. These are listed in order from best to worst case scenario.

Example #1

In this configuration the radio is mounted on the outside of the robot's structure, with the status LEDs pointed towards the outside of the robot.

This is the best configuration because it creates the least amount of interference for the radio's antennas. The status LEDs are visible and make it easy for field staff to read them. The radio is mounted relatively high on the robot. There are very few metal obstructions around the antenna.

Final Verdict: Best

Example #2

In this configuration the radio is mounted between the robot's a-frame, with the status LEDs pointed towards the outside of the robot. However, there is a transparent plastic panel covering the status LEDs.

This configuration is not the best but is still acceptable. The robot's a-frame is surrounding the sides of the radio, which will affect antenna performance. However, the plastic panel doesn't impact antenna performance, which allows the radio to create a good link with the field access point (AP).

Final Verdict: Acceptable

Example #3

In this configuration the radio is mounted between the robot's a-frame, with the status LEDs pointed towards the centerline of the robot.

This is not a good mounting location for the radio. First, field staff will have a harder time seeing the status LEDs, which will make it harder for them to help you troubleshoot your robot. More importantly, the radio is broadcasting its signal into the rest of the robot's structure. This configuration has a greater impact on antenna performance, and likely cause the robot to have communication problems with the field access point (AP).

Final Verdict: Not Recommended

Example #4

In this configuration the radio is mounted on a plate with the rest of the robot's electronics. The status LEDs are pointing upwards.

This scenario depends on other factors to determine if it could be satisfactory. In this specific example, the radio is broadcasting into an arm, which is going to negatively impact performance. If there were no obstructions above the radio, then this would be an acceptable configuration.

Final Verdict: Depends

Example #5

In this configuration the radio is mounted on a plate with the rest of the robot's electronics. The status LEDs are pointing downward (towards the ground).

This is one of the worst ways you can mount your radio. In this scenario the radio is broadcasting into the ground, which has a significant impact on performance. In this scenario the field access point (AP) will likely have a hard time maintaining a good connection to the radio throughout the match.

Final Verdict: Not Acceptable

How You Can Mount Your Radio

There are two recommended methods to mount your radio.

Zip Ties

The radio housing has two notches on either side. These notches are sized to fit a 1/4" wide zip tie (McMaster-Carr P/N 70215K57). When zip ties can be run through these notches and around a part of your robot's structure to rigidly mount the radio to the robot.

Removing the radio is easy, just cut the zip ties and unplug the cables.

VHB Tape

Another recommended solution is to use VHB tape. This is a high strength foam tape that can create a rigid mechanical connection between your robot and the radio.

Here are some examples of recommended VHB tape:

Thickness x Width

Supplier / Part Number

0.045" x 0.500"

McMaster-Carr / 8127A51

0.045" x 1"

McMaster-Carr / 8127A53

0.045" x 2"

McMaster-Carr / 8127A61

It's possible to remove the radio when using VHB, but keep in mind that VHB creates a more permanent bond than zip ties. Removing a radio mounted with VHB will require some force. Be careful not to damage your radio in the process of removing it.

Zip tie notches are included in the event that teams opt out of using VHB or another adhesive to attach the radio to their robots.

Custom Mount

Teams are more than welcome to design their own mounting solutions for the radio. However, there are some important considerations teams should make:

Do Not Fully Enclose The Radio

Creating a mount that encases the radio in a 3D printed or plastic housing traps heat. This can cause the radio to overheat during a match, which will cause the radio latency to increase.

What is Latency?

Latency is the amount of time is takes for packets of data to travel from one device to another. In the case of the VH-109 radio, it's the amount of time it takes for packets of data to travel from your driver station to the robot.

In other words, the higher the latency is the more delayed your controls will be. Normally this doesn't become noticeable to a driver until latency reaches around 120ms.

Under normal operating conditions, the latency between the radio and the driver station is no more than 5ms. When the radio gets hot, this latency will increase to around 40ms. While this is still well under the 120ms mentioned above, your radio will not be operating at peak performance.

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Last updated 5 months ago