Bluetooth Radio Signal Optimization in RVs
The RV Whisper Monitor Station (RVM1 or RVM2) collects data from sensors in the RV using Bluetooth radio signals. The RV Whisper Monitor Station must be able to see the Bluetooth radio signal of the sensors that are placed in different areas of the RV in order to work properly. In most RVs, the Bluetooth communications work just fine and there are no problems collecting data from the sensors.
However, after initial setup, some RVs have trouble with the Bluetooth signal between one or two sensors and the RV Whisper Monitor Station. This tends to happen most often in larger and heavier RVs like some Super-C RVs and 40+ foot Class A diesel pushers. Problems have also been known to occur in fifth-wheel trailers, particularly with the battery sensors.
The good news is that issues with these “problem sensors” can usually be resolved by moving the RV Whisper Monitor Station and/or some sensors to get all of the sensors to work reliably in the RV. This document provides information on how you can “tune the location” of your RV Whisper components to achieve reliable sensor readings.
How Does Bluetooth Work?
Bluetooth is a wireless technology that uses low-power, short-range radio signals to allow two devices to communicate with each other. When there is adequate radio signal strength (between the two devices) the devices can see each other’s radio signal. This lets the devices communicate with each other in a reliable way.
What Causes a Poor Bluetooth Signal in RVs?
As we touched on earlier, on the rare occasion that Bluetooth radio signal strength problems prevent a sensor from “working” in an RV, they tend to happen more often in larger and heavier RVs. Bluetooth radio signals have the longest range (up to 400 feet) when there is a direct line of sight with no objects between the two devices. When objects like RV walls, doors, floors, countertops, and cabinets are between any one sensor and the RV Whisper monitor station they all degrade the radio signal strength to some extent. In most RVs, this is not a problem.
Walls, floors, and doors in larger and heavier RVs are usually more solid which impacts the Bluetooth radio signal strength more. These heavier RVs might also have marble or granite countertops, ceramic floor tiles, stainless steel appliances, and solid wood cabinets. Sensor troubles due to low Bluetooth radio signal strength usually occur because multiple objects are between the “problem sensor” and the RV Whisper Monitor Station. Each of the objects between the devices reduces the radio signal strength some amount. When there are more objects in the “line of sight” between a sensor and the RV Whisper Monitor Station, the radio signal strength can be reduced enough to prevent the sensor from connecting with the RV Whisper monitoring station.
Battery Sensor Quick Tip
If you are having trouble with a battery sensor (like the BV2 or BMRV1 sensors), make sure the battery sensor is placed so that the batteries themselves are not in the “line of sight” between the sensor and the Monitor Station. Moving the sensor just a few inches so it is on top of the batteries can have a dramatic effect on improving the Radio Signal Strength for that sensor.
How to Optimize the Bluetooth Radio Signal in Your RV
If you are having trouble with the Bluetooth connections between the RV Whisper monitoring station and one of your sensors, it is usually a very easy fix. Most often, all that is needed to optimize the Bluetooth radio signal is to move the sensor and/or the Monitor Station. In many cases, just moving the sensor or Monitor Station a few inches can eliminate an obstructing object or two and establish a strong Bluetooth connection.
To start with, visualize what’s between the RV Whisper monitoring station and the sensor. Picture the “line of sight” between the two devices and identify all obstructing objects. Then move the sensor in whatever direction needed to establish a clearer line of sight.
Often, you might need to move the Monitor Station to a better location, depending on what is blocking the signal. For example, in larger RVs, the Monitor Station might need to be relocated towards the middle of the vehicle in order to send a strong enough signal to all of the sensors. Or, you may need to move the Monitor Station to be closer to (perhaps directly above) the battery compartment if your battery sensors are having Radio Signal Strength problems.
How Do I Know if I Have an Adequate Bluetooth Connection?
There is excellent data available to you in the RV Whisper application to help you resolve sensor location issues. The RV Whisper Monitor Station looks for Bluetooth sensor data every five minutes and logs the data along with a timestamp. One of the data points that is logged is the Bluetooth Radio Signal Strength Indicator (RSSI). You can see the RSSI values displayed in one of the data graphs for each sensor. The RSSI graphs let you see the impact of moving a sensor or the Monitor Station helping you “fine-tune” the ideal locations to get all sensors working reliably in your RV.
When the RSSI value is at -75 dB or better (e.g., -70 or -65) then you have a very strong Bluetooth radio signal. When the RSSI value is at -95 dB or worse (e.g., -100 dB or as bad as -105 dB), then you have a weak Bluetooth signal and probably have missing data from that sensor. Another possible indicator that the Bluetooth signal is weak is when the monitoring system goes longer than five minutes between logging data points. After changing locations, it is best to wait up to an hour before looking at the RSSI graphs for each sensor. Comparing “before” and “after” RSSI values should help you quickly find the sweet spot for your sensors and Monitor Station.
If you cannot see any data at all from a sensor, then there is a possibility that the sensor might not be working at all. If you believe this might be the case, temporarily move the sensor to a countertop or someplace close to the monitoring station, or temporarily move the Monitor Station to be very close to the sensor. Wait 20 minutes or so to make sure it works and that the monitoring station is picking up sensor data. Then slowly move the sensor to where you want it and monitor the RSSI graphs for that sensor after each placement.
If you are still unable to optimize the Bluetooth radio signal between your RV Whisper monitoring station and one of the sensors even after moving the sensor and/or station to different locations, contact our technical support (support at rvwhisper.com) for further assistance.