Table of Contents
Introduction
Recently there has been an announcement of a fairly big technical change in the Australian Helium network. This has to do with what frequencies the network operates on. Today the Helium network in Australia operates in the AU915 band (not to be confused with US915).
However the network will soon be switching to AS-923-1 band. Let’s get into some of the details to understand what this means for the network and for you.
What does Helium frequency mean?
Helium miners transmit and receive signals over the air. Like FM, radio and cell phone transmissions these signals are at specific frequencies. All Helium miners in Australia use a set of frequencies called AU915. This is a different set of frequencies from the USA for instance which uses US915.
How to change the frequency of my Helium Miner?
The frequency of a Helium miner cannot be changed by a user. A helium miner operates on the frequency depending on the region it is operating or asserted in. For instance a miner located and operating in the USA will beacon and witness on frequencies in the US915 list.
What are the frequencies for AU915 ?
The frequency range for AU915 is 916 MHz – 928 MHz. Here is a complete list of AU915 frequencies. A Helium miner will transmit signals at these frequencies. In the transaction below, a beacon is transmitted at 918 MHz which is within this frequency range.
What are the frequencies for AS923-1?
The frequencies for AS923-1 range from 922 MHz to 925 MHz. There are specific center frequencies for the LoRA transmissions within that range. Here is a complete list of AS923-1 frequencies.
What does the switch from AU915 to AS-923-1 mean?
The switch in frequency range means that miners that are currently transmitting beacons in the range of 916 MHz to 928 MHz will begin to transmit over a narrower range of frequencies from 922 MHz to 925 MHz and at a lower power level relative to the current limit.
What are the Pros of the switch to a different frequency plan?
Working with large network operators
Large public operators (NNNCo, Spark, Ventia) and organizations (Sydney Water, Urban Utilities) in Australia use the AS923-1 band and it’s important for devices to work with these networks. There is however one operator that uses the AU915 band (TTN)
Roaming
It is easier for Helium IoT devices to roam from one country to another in the region is easier as most countries around Australia and New Zealand use AS923-1. So you can imagine if your IoT device like an asset tracker were to move from Australia to Malaysia for instance, it would disappear from the network if the frequencies were not the same.
Reduced RF Interference
In Australia, 5G is being rolled out in a number of sub 1 GHz bands. One of them includes the range of frequencies 890 MHz to 915 MHz.
In the above image we have shown 5G bands, AU915 bands and the relatively smaller AS923-1, 2, 3 and 4 bands. AS923-1 is the widest of the AS923 bands and furthest away from the Australian 5G band.
By moving the Helium operating frequencies further away to 922-925 MHz, there’s more opportunities to reduce interference with the use of an RF filter for instance.
What are the Cons of switching to a different frequency plan?
Power limitation and range
Devices operating at the AS923-1 frequency are allowed a maximum power output of +16 dBm or 40 mW. The AU915 band has a max output power of +30 dBm or 1 Watt.
This means that IoT gateway and device transmissions will have to reduce their output power by 14 dB or 96%.
When power is reduced it has direct implications on range. In small city with many Helium miners that’s not an issue, but when you consider the large area of Australia it has significant impact for nationwide Helium network coverage as many more miners will be required.
Practical concerns for devices currently in the field
The most important consideration is that Helium miners in the field should continue to operate as normal. There is uncertainty around some of the miners in the field like the Bobcat 300 – US915 miners did not work in Australia for instance. However our recommended miners for Australia should operate normally.
Wider frequency range = more flexibility
A wider frequency range allows multiple options for transmission and reception of signals. Think of it like a highway. With more lanes more cars can be accommodated. A wider band enables a miner to increase capacity, transfer more data and avoid radio interference. So the switch to a narrower frequency range is very limiting.
What is the frequency of AS923-1?
AS923-1 uses the following center frequencies in the range: 922 MHz – 925 MHz
- 923.2 MHz
- 923.4 MHz
- 922.2 MHz
- 922.4 MHz
- 922.6 MHz
- 922.8 MHz
- 923.0 MHz
- 922.0 MHz
- 923.6 MHz
- 923.8 MHz
- 924.0 MHz
- 924.2 MHz
- 924.4 MHz
- 924.6 MHz
What is the frequency of AU915?
Helium frequency band AU915 in Australia uses the following frequencies in the range 916 MHz to 928 MHz
UPLINK
| Frequency (MHz) |
|---|
| 916.8 |
| 917.0 |
| 917.2 |
| 917.4 |
| 917.6 |
| 917.8 |
| 918.0 |
| 918.2 |
| 917.5 |
DOWNLINK
| Frequency (MHz) |
|---|
| 923.3 |
| 923.9 |
| 924.5 |
| 925.1 |
| 925.7 |
| 926.3 |
| 926.9 |
| 927.5 |
| 923.3 |
Summary
In this post we have discussed the move in Australian Helium frequencies. We anticipate this transition to occur some time in 2022.