XinaBox produce several LoRa xChips (the RL01, RL02 and RL03 - referred to collectively as RLxx). We also produce LoRa cores (CR01, CR02 or CR03).
When you buy a kit with a LoRa xChip included it comes with an antenna. But when you buy the xChips loose the antenna is not included and you will need to buy one, or make your own.
This page is designed to help you get the right antenna for your xChip, and includes the following sections:
Please note that antenna engineering is a complex topic - we are just skimming the surface here, enabling you to use your XinaBox LoRa xChips :)
There are a broad range of suitable antenna and all the big electronics retailers stock them. But there are so many options on the market that it can be daunting trying to find the right one! Follow the guidelines below to ensure you get the right antenna for your RLxx:
- You need an antenna that can screw onto the RLxx. Look for one with MOUNT = SMA MALE.
- Check that the MHz range of the antenna includes the range of the specific RLxx xChips that you have (see below). So, an antenna that has a range of 868MHz to 915MHz would be suitable for the RL02 and RL03.
The only difference between the 3 RLxx xChips is the range that they use to transmit:
- RL01 = 434MHz,
- RL02 = 868MHz,
- RL03 = 915MHz
Here is an example of an antenna that is just right for the RL03... choose the SMA connection option.
- There are no other criteria that are important. There is no such thing as a 'LoRa antenna' so be dubious if you hear that phrase.
- XinaBox do not manufacture antenna - we use 3rd party ones and they are usually below 10USD to buy. Shop around if the price is much greater than that.
- Sometimes they are straight, sometimes they are angled, some even pivot. Any of these options is fine.
- Some antennae will advertise a centre frequency (say, 900MHz) and will claim to handle a bandwidth of ± 30MHz, This means it would be suitable for the range of 870-930MHz. This would work well for the RL03 - it might work OK for the RL02, but maybe not.
It is possible, simple even, to make your own antenna. It is also a great way to learn some of the core principles of radio transmission. The process is described below:
- Start with a Male SMA connector and 2 pieces of wire.
- Go to this webpage to calculate how long the pieces of wire need to be. Note - for 868 Mhz you would need 2 wires each 82.17 mm long
- Solder / glue / fix the wires to the SMA connection as shown in the image below.
- Screw the antenna into the RLxx - all being well it should work just fine!
Although building a functioning antenna is quick and easy, the science behind antenna engineering is deep and fascinating. Take a look at the content of this professional course in Antenna Engineering offered by Georgia Tech to get a sense of the depth and complexity of this subject.
There is more info about the antenna in the video below. The full video will give you loads of additional information about LoRa radio:
Wi-Fi and Bluetooth are globally defined technologies. This means that they conform to a standard that is consistent across the world: Wi-Fi in Washington works the same as Wi-Fi in Wuhan, and Bluetooth in Brazil works the same as Bluetooth in Belarus. These global standards include the frequency range on which their signals are allowed to be transmitted.
When using Wi-Fi or Bluetooth we don't need to worry about local legislation that relates to radio transmission. The Bluetooth or Wi-Fi device will comply with the global standard and will therefore not violate any local standards.
For LoRa there is no global standard.
All countries have some restrictions on how citizens are allowed to use radio waves. For example, air traffic control will use a specific frequency, and it is usually highly illegal and always very dangerous to transmit on this restricted bandwidth.
This means that, across the world, there are a range of local laws that apply to how LoRa radio can be used. In particular, the bandwidth that is available to LoRa is different in different parts of the world, and local laws apply to how LoRa radio can be transmitted. For example, in most countries a LoRa radio cannot transmit non-stop. it has to transmit in 'duty cycles'. This discussion forum shines a light on the scope and complexity of some of the issues people have to consider.
Although no global standard has been defined, there are effectively 3 global regions that each have a different 'approach' to LoRa. The ideal LoRa xChip for you depends on the territory / region in which you intend to use it:
- RL01 / CR01 = 434MHz: OK for Region 1
- RL02 / CR02 = 868MHz: OK for Region 1
- RL03 / CR03 = 915MHz: OK for Region 2
- There is no agreed standard across Region 3 so please ensure you check local ordinances and choose your xChip accordingly.
- There will be local ordinances governing how LoRa is used where you live. XinaBox cannot be responsible for xChips being used in ways that are contrary to local laws.
- There are 2 options that are suitable for Region 1. Lower frequency gives greater range.