When I was looking at designing the Level Up module I wanted to get a sense of any pain points and the reasons that would trigger purchasers to return their products. It didn’t take long before I noticed a common thread. The commenters were clearly frustrated with two aspects, but we are going to focus on the bluetooth connectivity issues in this post.
So in this blog post I wanted to set some realistic expectations on what you can expect from your RV leveling gadgets that use Bluetooth. This advice isn’t just for our Level Up product but for all products that fall under this class of device, regardless of the label on the product. I am not here to single out or bash any particular brand, I just want to improve your success, and reduce frustration with the product that you purchased.
I think part of the problem is the theoretical marketing hype can lead to some unrealistic expectations of what the range of Bluetooth radios are capable of under real world conditions. I see videos online that claim (and I am sure they are true) that they can successfully connect two bluetooth transceiver’s tens of km away. Well sure… but both radios need to be on top of mountains with a clear line of site, use high gain directional antennas, and non-existent throughput (data rate). But hey, they connected. Nice experiment… but not even close to practical for real life.
I am not going to bury the lead any longer. If there is one take away here, it can be summarized as “the closer the better”, and if your thinking well duh, then don’t bother reading any further.
If your still here, I guess you’ve decided to stick around.
Aside from inaccurate or inconsistent levelling, and battery life, I would have to say the most frustrating aspect of this product class is a failure to connect when you need it to. I know that for myself when I was testing Level Up Pro with our trailer and truck, my tolerance for connection failures was zero.
Getting setup in busy campgrounds can be stressful. Your dealing with trying to get the trailer in the perfect spot, close to electrical, water, sewer, avoiding stumps, trees, curbs, fire pits, and potentially blocking off traffic for an extended amount of time. The last thing you want is to do is fight with your electronic devices to get and maintain a connection only to have it disconnect a few seconds later. Personally I knew that unless it reliably connected 10 times out of 10, I would be… what’s the word am I looking for…. lets go with upset. Anything less than that I would abandon it and just level the trailer manually. But hey that’s just me.
Theoretical vs Actual
When Bluetooth radio manufacturers provide specifications they typically give you best case scenarios. After all they have no idea how their product is going to be used in the real world. The perfect scenario is you standing in a open field or parking lot 30 meters (100 ft) from the device with no obstructions. That’s great, but that doesn’t accurately reflect real world usage.
There are all kinds of factors that affect the coverage range of a device. Even the implementation of Bluetooth in you mobile device can negatively impact the coverage range. I am only going to mention a few factors here as I don’t want to get lost in the weeds.
Device Specifications
Not all bluetooth radios are built the same. The radios are typically classified into one of four groups. The main difference in the classifications is transmit power.
Increasing the transmit power of device is helpful, but it only address’s one side of the problem. You can’t change the receiver gain so you end up with a link imbalance (i.e. you can talk-transmit but can’t hear-receive). Yes, a different antenna with more gain will help, but now you have other components that needs to be installed, external antenna, coax cables and connectors.
Propagation Loss
This is the degradation of signal between the transmitter and receiver over distance. Bottom line is the further you are way from the other device the larger the path loss. i.e. weaker the signal. The weaker signal means lower data rates.
My rule of thumb is to take our theoretical maximum for class 1.5 device of 30 meters (100ft) and divide it by 4. Then take the 7.5 (25ft) meter result and cut that in half. You’ll end up with a maximum distance of around 3.75 m (12.5 ft). If you can install the device in your trailer and have your mobile device while in the cab of your tow vehicle be less than 3.75 meters or (12.5ft) you have a excellent shot at success. I am not going to guarantee it, as I don’t know your exact situation. Treat this as a starting point, remember I started this section with this is a rule of thumb. Is there some flexibility… absolutely. We’ll talk about some real world practical things you can do in a bit.
Attenuation
Attenuation is a reduction of signal signal strength (and thus range) due to obstructions and distance. Obstructions in this scenario are your tow vehicle, your trailer, propane tanks, batteries, everything in the back of your truck, etc. Bottom line everything between you and the Bluetooth gadget (including you) attenuates (reduces) the signal.
RF Radio Antenna
Most Bluetooth modules in this class use built in antennas. They are simple, reliable and don’t rely on any installation. These built in antennas are generally “printed” on the circuit board and have low to no gain. They work, but they are less than ideal.
Interference
I will make this an honorable mention. Normally this would make the main list, but because of where you would typically use your leveling product it’s “likely” not an issue. If your leveling your trailer in your driveway or in dense urban locals this could be a factor, but in remote campgrounds this is not likely to be an issue. Still… something to be aware of.
All Bluetooth radios operate in the same band (2.4 GHz ISM) and they share that band with other radio services such as WiFi, Smart Home devices, baby monitors, cordless phones, security cameras, Microwave ovens, etc, etc, etc. Its an unlicensed band and it is a bit like the wild west, it can pretty much be used for whatever (all right I maybe exaggerating a bit).
What You Can Do
When your talking about wireless connections the best thing you can do is maintain line of site (LOS). LOS is exactly like it sounds, I can see the device I am connecting too. Ever wonder why rural cell towers are on top of hills? The problem is we live in the real world and wireless connections are never perfect, and there is likely one or more obstruction in our way. The fewer the obstacles the better more reliable connection you can expect.
To avoid duplicating content, I have included the link from the Level Up manual for Bluetooth Range Expectations. While it is written for Level Up it applies to any product in this category.
For those of you that don’t want to see a single mathematical formula, there is an easy sure fire method of ensuring you have the best chance of connecting your device reliability before installing it.
Measure it.
- Hook up your RV (or at least place the tongue of the trailer over the ball)
- Make sure the Bluetooth module is mounted in the proposed location using double sided tape (not the permanent kind)
- ensure the device is on
- sit in the cab of your truck with the windows up and the doors closed and ensure that you can connect and maintain a connection with the Bluetooth module.
- Disconnect and try an reconnect a few times to ensure that the results are consistent.
If you have the room, try “connecting” the trailer at a sharp angle to maximize the distance and obstructions between the module and your mobile device. Try and connect multiple times to ensure that connection is still reliable.
If that doesn’t work try an alternate location. The bottom line is the closer the device is to the front of the trailer the more reliable the connection becomes and the happier you will be. The last piece of advice is to use the tools available from your manufacturer to help you determine the best installation location. If you use the setup wizard in our oneView application while setting up your Level Up module you will find that on step three it will give you the signal strength in dBm. The closer that number is to zero the better. If the negative number is confusing just pretend the negative sign doesn’t exist and make sure the result is as close to zero as possible. Just know that you will never see anything better than -40 dBm.
Finally, be aware, that most devices in the market including Level Up are not IP-67 rated (i.e. waterproof), so if your tempted to install the device at the front of the trailer near the propane tanks or batteries, you will need to install it in a outdoor rated plastic (ABS) enclosure.
That’s it for today. Cheers!