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Wireless LAN In Australia

Cable data    Antenna    2.4 GHz     5 GHz    900 MHz    Power limits    IEEE 8011b    Basic info    RF Power Table    802.11 and VK Amateurs    Information for newcomers    UWB

Wireless LAN Links 

For up to date information please check the ACMA database

The information on this page was updated for Australian conditions as of January 21 2006; like all information on the web it may not be completely accurate, please also check other sources.

This page is designed  to help people set up wireless links; home or office wireless networks are covered at other web sites, if you would like this information included in this site please drop me an email.


Wireless LAN on 2.4 GHz

IEEE 802.11b

IEEE 802.11b (Wi-Fi) uses DSSS, using 22 MHz of bandwidth (passband) to transmit data with speeds of up to 11 Mb/sec. A Wi-Fi system can use any of 13 22-MHz-wide sub-channels across the allocated 83.5 MHz of the 2.4 GHz frequency band.

Overview
Standard Transfer Method Frequency Band Data Rates [Mbit/s]
802.11b DSSS, HR-DSSS 2.4 GHz 1, 2, 5.5, 11 Mbit/s

A maximum of three Wi-Fi networks can coexist without interfering with one another.

Countries outside of the United States may support more or fewer than 11 selectable sub-channels.

Most equipment commonly available in Australia is designed for the 11 channel American market.

Australian 2.4 GHz Wi-Fi channels are shown below:

22 MHz wide Direct Sequence Spread Spectrum, 5 MHz channel spacing.
Channel       MHz
1                 2412†
2                 2417†
3                 2422
4                 2427
5                 2432
6                 2437
7                 2442
8                 2447
9                 2452
10               2457
11               2462
12               2467
13               2472

2400 MHz - 2483.5 MHz Not exceeding 4 Watts EIRP

Information for antenna building: 1/2 wavelength is 61mm, and 1/4 wavelength is 30.5mm.

 

IEEE 802.11g

This encoding standard was ratified in June 2003. This standard works in the 2.4 GHz band like 802.11b, but operates at 54 Mbit/s raw or about 24.7 Mbit/s net throughput like 802.11a. It is fully backwards compatible with 802.11b.
The 802.11g standard swept the consumer world of early adopters starting in January 2003, well before ratification. The corporate users held back and Cisco and other big equipment makers waited until ratification. By the end of 2003, announcements were flourishing. Most of the dual-band 802.11a/b products became dual-band/tri-mode, supporting a, b, and g in a single card or access point.

Overview
Standard Transfer Method Frequency Band Data Rates [Mbit/s]
802.11g DSSS, HR-DSSS, OFDM 2.4 GHz 1, 2, 5.5, 11; 6, 9, 12, 18, 24, 36, 48, 54 Mbit/s

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Power Output on 2.4 GHz

In Australia 4watts is the total Radio Frequency (EIRP) power allowed from Channel 1 to 13.
This means that you aren't allowed to transmit in any direction with more power than what a 4Watt transmitter with a 0dBi antenna would transmit in that direction.
Note: 4Watts = 36dBm = 6dBW
Equivalent power output(dBm) = power in (dBm) + antenna gain (dBi)
Equivalent power output(dBW) = power in (dBW) + antenna gain (dBi)

Most "omni-directional" antenna's aren't quite omni (don't transmit straight up very much) and hence are usually about 8dBi.
So this means that you're only allowed to put in 28dBm (631mW) of power into an 8dBi antenna.

If using a 21dBi dish then you're only allowed to put in 15dBm (31mW) into that dish.

ACMA database

RF Power Table

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13 CM Amateur band plan
Complete Amateur Radio Band Plans

Amateur operation is permitted between 2300 - 2302 and 2400 - 2450 MHz.

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Possible Interference signals (Wide Band)

Amateur TV

18 MHz FM signal on 
ATV CHANNEL 1 FM TV
2406.000 - 2424.000
and
ATV CHANNEL 2 FM TV 18 MHz wide
2430.000 - 2448.000

There are now 8 MHz wide digital TV transmissions on channel 1 and 2 in the Brisbane area.

Other signals

These frequencies are also used by low power FM TV Transmitters (extenders), phones, video and audio links.

The Wireless LAN frequencies are shared with other users including Amateur.

Amateurs using this mode are not limited to 4 Watts EIRP power as long as they stay in the Amateur segment.
Other voice, TV and data users also share this frequency range.
ACMA database

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Suggestions to help minimize future interference on the 2.4GHz band

The most likely source of wide band interference to Wireless LAN on 2.4GHz is 18 MHz wide FM Television; although there are many low power transmitters in use, Amateurs can use high power equipment.

There is some ATV activity on 2.4 GHz in Brisbane, as far as I know only 3 stations have over 1 Watt of amplifier output power although high gain antenna are used.
One station can use 50 Watts of 18 MHz wide FM into high gain antenna (20db+).
There are now Amateur digital TV transmissions on 1.2 GHz and 2.4 GHz.

It is interesting to note that some ATV stations in other states have started going to higher power due to the background noise raising on 2.4GHz (wireless LAN), I would like to prevent this happening in the Brisbane area.
One of the Brisbane ATV repeaters has had a 2.4 GHz input for a number of years.

The Queensland Digital Group (QDG Inc.) and the South East Queensland Amateur Television Group (SEQATV Group) came to an agreement some years ago to help reduce interference between ATV and Data links on the Amateur 70 CM band; ATV uses Horizontal antenna, Digital uses vertical antenna and all links use the minimum power needed and narrow beamwidth antenna.

The majority of wireless LAN seems to be using vertical and ATV users need to use horizontal antenna for distance work so I suggest that data transceivers use vertical antenna to help prevent interference; with any luck commercial users will follow our lead. In this way all users will be more able to share the limited frequency resource.

Some of the new antennas that are being used for data are horizontally polarized, these are ok if not used in a prime location but are more likely to pick up unwanted signals.

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Wireless LAN on 900 MHz

915 MHz-928 MHz Not exceeding 1W EIRP

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Wireless LAN on 5 GHz

IEEE 8011.a

5150 MHz - 5350 MHz Not exceeding 200mW EIRP

5725 MHz - 5850 MHz Not exceeding 4W EIRP

Overview
Standard Transfer Method Frequency Band Data Rates [Mbit/s]
802.11a OFDM 5.2, 5.5 GHz 6, 9, 12, 18, 24, 36, 48, 54 Mbit/s


Channel 36 5180 MHz 200mW EIRP

Channel 40 5200 MHz 200mW EIRP

Channel 42 5210 MHz 200mW EIRP

Channel 44 5220 MHz 200mW EIRP

Channel 48 5240 MHz 200mW EIRP

Channel 50 5250 MHz 200mW EIRP

Channel 52 5260 MHz 200mW EIRP

Channel 56 5280 MHz 200mW EIRP

Channel 58 5290 MHz 200mW EIRP

Channel 60 5300 MHz 200mW EIRP

Channel 64 5320 MHz 200mW EIRP


Channel 149 5745 MHz 4W EIRP

Channel 152 5760 MHz 4W EIRP

Channel 153 5765 MHz 4W EIRP

Channel 157 5785 MHz 4W EIRP

Channel 160 5800 MHz 4W EIRP

Channel 161 5805 MHz 4W EIRP

Channel 165 5825 MHz 4W EIRP

Not all channels are implemented in current equipment.

For up to date information please check the ACMA database

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Possible Interference Signals (Wide Band)

Amateur TV
ATV  5680.000 - 5760.000 MHz
ATV  5740.000 - 5760.000 MHz
ATV  5810.000 - 5830.000 MHz

DATA
Data 5700.000 - 5720.000 MHz
Data 5770.000 - 5830.000 MHz

Voice
Voice 5720.000 - 5740.000 MHz
Voice 5790.000 - 5810.000 MHz

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6 CM Amateur band plan
Complete Australian Amateur Radio Band Plans (March 2005)

Amateur operation is permitted between 5650 - 5850 MHz.

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Australian power limits

915 MHz - 928 MHz Not exceeding 1W EIRP

2400 MHz - 2483.5 MHz Not exceeding 4W EIRP

5150 MHz - 5350 MHz Not exceeding 200mW EIRP

5725 MHz - 5850 MHz Not exceeding 4W EIRP

EIRP = Effective Isotropic Radiated Power.

For up to date information please check the ACMA database

Notes:

Three 802.11b/g Wi-Fi networks can coexist without interfering with one another if channels 1, 6 and 11 are used in Australia for the full 4 Watts EIRP,  this gives a 25 MHz channel spacing.

ACMA database

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IEEE 802.11b Wi-Fi 

IEEE 802.11b Wi-Fi 2.4 GHz standard supports true multipoint networking with such data types as broadcast, multicast, and unicast packets.

 The MAC address built into every device allows a virtually unlimited number of devices to be active in a given network. 

These devices contend for access to the airwaves using carrier sense multiple access with collision avoidance (CSMA/CA).


The Wi-Fi physical layer uses direct-sequence spread spectrum (DSSS) at four different data rates using a combination of differential binary phase-shift keying (DBPSK) for 1 Mb/sec, differential quaternary phase-shift keying (DQPSK) for 2 Mb/sec, and QPSK/complementary code keying (CCK) for the higher speeds: 5.5 and 11 Mb/sec.


The RF power level is typically between 30 and 100 mW (up to 20 dBm) in most commercial WLAN systems but cards are available with 300 mW output.

Since this was written 802.11g has become the standard on 2.4 GHz, this is a 54 Mbps standard that is backwards compatible with 802.11b.

 

RF Power Table

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802.11 Overview
 

Standard Transfer Method Frequency Band Data Rates
802.11 legacy FHSS, DSSS, IR 2.4 GHz, IR 1, 2 Mbit/s
802.11b DSSS, HR-DSSS 2.4 GHz 1, 2, 5.5, 11 Mbit/s
"802.11b+" non-standard DSSS, HR-DSSS (PBCC) 2.4 GHz 1, 2, 5.5, 11, 22, 33, 44 Mbit/s
802.11g DSSS, HR-DSSS, OFDM 2.4 GHz 1, 2, 5.5, 11; 6, 9, 12, 18, 24, 36, 48, 54 Mbit/s
802.11a OFDM 5.2, 5.5 GHz 6, 9, 12, 18, 24, 36, 48, 54 Mbit/s

 

IEEE 802.11 or Wi-Fi

IEEE 802.11 or Wi-Fi denotes a set of Wireless LAN standards developed by working group 11 of IEEE 802.

The 802.11 family currently includes three separate protocols that focus on encoding; other standards in the family are service enhancement and extensions, or corrections to previous specifications. 802.11b was the first widely accepted wireless networking standard, followed, paradoxically by 802.11a and 802.11g.

Protocols

802.11a
In 2001, a faster relative started shipping, 802.11a, even though the standard was ratified in 1999. The 802.11a standard uses the 5 GHz band, and operates at a raw speed of 54 Mbps, and more realistic speeds in the mid-20 Mbps. 802.11a has not yet seen wide adoption because of the high adoption rate of 802.11b, and concerns about range: at 5 GHz, 802.11a cannot reach as far with the same power limitations, and may be absorbed more readily. Most manufacturers of 802.11a equipment countered the lack of market success by releasing dual-band/dual-mode or tri-mode cards that can automatically handle 802.11a and b or a/b/g as available, or access points which can support all standards simultaneously. 802.11a has 12 non overlapping channels, 8 dedicated to indoor and 4 to point to point. Different countries have different ideas about support, although a 2003 World Radiotelecommunciations Conference made it easier for use worldwide. A mid-2003 FCC decision may open more spectrum to 802.11a channels as well.

802.11b
802.11b has a range of about 150 feet (50 meters) with the low-gain omnidirectional antennas typically used in 802.11b devices. 802.11b has a maximum throughput of 11 Megabits per second (Mbps), however a significant percentage of this bandwidth is used for communications overhead; in practice the maximum throughput is about 5.5 Mbps. Metal, water, trees, and particularly thick walls absorb 802.11b signals and decrease the range drastically. 802.11 runs in the 2.4 GHz spectrum and uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) as its media access method.
With high-gain external antennas, the protocol can also be used in fixed point-to-point scenarios (5 miles/8 kilometres), reports of up to 50-75 miles (80-120 kilometres) line of sight) to replace costly leased lines, or in place of very cumbersome microwave communications gear. Current cards can operate at 11 Mbps, but will scale back to 5.5, then 2, then 1, if signal strength is an issue. 802.11b divides spectrum in 14 overlapping, staggered channels of 22 megahertz (MHz) each. Different channels or ranges are legal in different countries. Three or four channels may be used simultaneously in the same area with little or no overlap, typically 1, 6, and 11.

802.11g
In June 2003, a third standard for encoding was ratified: 802.11g. This version works in the 2.4 GHz band, but operates at 54 Mbps raw or about 22 Mbps net throughput. It is fully backwards compatible with b, and details of making b and g work together well occupied much of the lingering technical process. The 802.11g standard swept the consumer world of early adopters starting in January 2003, well before ratification. The corporate users held back and Cisco and other big equipment makers waited until ratification. By June 2003, announcements were flourishing. Most of the dual-band 802.11a/b products became dual-band/tri-mode, supporting a, b, and g in a single card or access point.

Certification
Because the IEEE only sets specifications but doesn't test them, a trade group called The Wi-Fi Alliance runs a certification program that members pay to participate in. Virtually all companies selling 802.11 equipment are members. The Wi-Fi trademark, owned by the group, guarantees interoperability. Currently, Wi-Fi can mean any of 802.11a, b, or g; by fall, Wi-Fi also includes the security standard Wi-Fi Protected Access or WPA. Products that say Wi-Fi are supposed to also indicate the band in which they operate in, 2.4 or 5 GHz.

Standards

The following standards and task groups exist with the working group:

* IEEE 802.11 - The original 2 Mbit/s, 2.4 GHz standard
* IEEE 802.11a - 54 Mbit/s, 5 GHz standard
* IEEE 802.11b - Enhancements to 802.11 to support 11 Mbit/s (1999)
* IEEE 802.11d - new countries
* IEEE 802.11e - enhancements: QoS, including packet bursting
* IEEE 802.11f - Inter-Access Point Protocol (IAPP)
* IEEE 802.11g - 54 Mbit/s, 2.4 GHz standard (backwards compatible with b)
* IEEE 802.11h - 5 GHz spectrum and transmit power management for European compatibility
* IEEE 802.11i - Enhanced security
* IEEE 802.11j - Extensions for Japan
* IEEE 802.11n - higher throughput improvements

Community networks

With the proliferation of cable modems and DSL, there is an ever-increasing market of people who wish to establish small networks in their homes to share their high speed Internet connection. Wireless office networks are often not protected and let "people on the street" connect to the internet.
There are also efforts by volunteer groups to establish wireless community networks to provide free wireless connectivity to the public.

Security

In 2001, a group from the University of California at Berkeley presented an paper describing a weakness in 802.11b described by Fluhrer, Mantin, and Shamir entitled "Weaknesses in the Key Scheduling Algorithm of RC4". This presentation was soon followed by Adam Stubblefield and AT&T publicly announcing the first verification of the attack. In the attack they were able to intercept transmissions and gain unauthorized access to wireless networks.

The IEEE set up a dedicated task group to create a replacement security solution, 802.11i (previously this work was handled as part of a broader 802.11e effort to enhance the MAC layer). While 802.11i is still a work in progress, and is not expected to be completed until late 2003, the Wi-Fi Alliance has announced an interim specification called Wireless Protected Access (WPA) based on a subset of the current IEEE draft. These started to appear in products in mid-2003, and implementation will be mandatory by September 2003 in order to display the Wi-Fi logo.

The above information was written before September 2003.

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Basic information for Amateurs

The Amateur and 2.4 GHz ISM bands overlap, all the commercial equipment will operate in the Amateur band.

Why not have a central server?
The problem with having a central server is there are only three frequencies you can use in one location before the channels overlap.
There are a large number of users  in this ISM band so a large powerful site is not a good idea in a city area, you can get away with this in the country for now.
A series of small cells with links is the only way things can work once a more than a few people link together.

Why not use an amplifier?
While you can get amplifiers for this band it's easy to get very high antenna gain.
There are come commercial sites that are using amplifiers and low gain omni antenna but they still keep to 4Watts EIRP.

How do I start?
The simplest way to get going is to purchase an AP and plug in an external antenna.
It is best to check prices first as equipment is coming down in price fast and some of the group hardware purchases are very good.  Most of the local retailers have VERY high mark-ups.

Prices have dropped considerably and there is now a lot of equipment available. (July 2005)

This page has a few links:
Wireless LAN Links

There are a number of wireless LAN groups that have a lot of information on their Web sites and group discounts on components.
This one of the Brisbane groups:
Brisbane Mesh

Both the SCARC and QDG are setting up Amateur networks but the only way of extending them is to use non Amateur links, so we are working with Bresmesh and others.

SCARC Amateur Radio Network

Brisbane Mesh

APANA

Spend some time looking at the mail archives on the sites and the help pages so you get some idea of what others are doing.

Antennas
You can modify second hand ex pay TV antennas, build your own, or buy one from a local or overseas supplier.
The price varies greatly due to VERY high mark-ups, 500% from some suppliers.
These are the maximum prices you should be paying:
Rojone

There are a large number of antenna links on this page: Antenna Links

What coax do I use?

Loss at 2.4 GHz

Times Microwave

LMR 1700 -- 1.7db loss / 33.3m     $70.00 approx per meter
LMR 1200 -- 1.99 db loss / 33.3m
LMR 900 -- 2.63 db loss / 33.3m  $40 approx per meter
LMR 600 -- 4.4 db loss / 33.3m
LMR 500 -- 5.48 db loss / 33.3m
LMR 400 -- 6.8 db loss / 33.3m  $4.00 approx per meter
LMR 300 -- 10.4 db loss / 33.3m
LMR 240 -- 12.9 db loss / 33.3m
LMR 100A -- 70.1 db loss / 33.3m

Andrew

1 5/8"  LDF-- 1.4 db loss / 33.3m
1 1/4" LDF -- 1.7 db loss / 33.3m
7/8" LDF -- 2.3 db loss / 33.3m
1/2" LDF -- 3.9 db loss / 33.3m Approx LMR 600 size 
1/2" Superflex -- 6.17 db loss / 33.3m Approx LMR 600 -- Flexible
3/8" LDF4-50A -- 3.3 db loss / 33.3m 
3/8" Superflex -- 6.84db loss / 33.3m

Other Companies 

CNT-400  -- 6.7 db loss / 33.3m $3.70m approx per meter
Belden 9913 -- 7.7db loss / 33.3m 

RG213 -- 15.2db loss / 33.3m
RG214 -- 15.2db loss / 33.3m double shielded
RG58 -- 32.2 db loss / 33.3m 

You also need to include connector loss. 

This page has cable links 

Wireless LAN Links 

Wireless LAN FAQ    

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Information for newcomers

Older 802.llb PCMCIA cards and access points can be obtained second hand or old stock from $20.00 or less,
these are good for long distance use as the higher speed 802.11g cards slow down to these speeds as the
signal level reduces anyway; after saying this, the newer equipment generally have better receivers so if
you have the money go for the latest models.
You can now get even faster 108 Mps cards but they are still proprietary; the new standard (802.11n) should
be out in a year or so.

If you wish to use 2.4 GHz to connect to another amateur you need someone within line of sight, a card or
wireless router with an external antenna and no or very very very few trees in the path. The links on the
QDG wireless pages will give you a lot of information and many hours happy browsing.
If you are in the Brisbane Australia area he best way to check out if you are line of sight to somewhere is to list your location as a node on the Brismesh nodes page http://www.brismesh.org.au

A few points to note

Please note the antenna radiation pattern of your antenna; it is no use placing typical a high gain omni
antenna at your location if you live on a hill, unless of course you only wish to connect to other people
on hills.

Aligning antennas

Directional antennas such as Yagi, grid packs and dishes are very directional (thatís how they get the
gain), after aligning them by sight you will need professional equipment or a cheaper equivalent.

The cheaper equivalent

The access points often have an indication of signal strength and noise level that you can use if you have
nothing better.

One low cost way of aligning antennas is to use a laptop with a wireless card that has provision for an
external antenna, connect the antenna you are aligning to this card; use free software such as Network
Stumbler to give an indication of signal and noise level. I keep two 802.11b cards for this purpose.
The other end of the link will need either an access point or another card in beacon mode while the
alignment is taking place.

Some basic antenna theory will be of help here, please have a look at the antenna links on this site.

Alan VK4YAR 23 July 2005

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802.11 and VK AMATEURS
 

Len Bray, Deputy Manager Spectrum Planning Team, Radiofrequency Planning Group of the ACA has written to our AR Magazine Editor Colwyn Low with comment on the article "802.11 Protocol and Ham Radio". which appeared in the September 2003 issue of AR magazine. The article discusses opportunities for amateur radio operators to use 802.11 technologies, mainly in spectrum around 2.4 GHz.
The article makes reference to the Rules and Regulations of the Federal Communications Commission in the USA for information on what is provided for under those regulations, both in terms of what is authorised specifically for amateur radio and generally for short-range 802.11 applications in that country. Unfortunately, the article does not refer to the regulatory arrangements that apply in Australia. A reader could be excused for believing that USA regulation somehow directly applies to Australia, or that there are no applicable Australian regulatory arrangements.

I encourage Amateur radio operators wishing to experiment with 802.11 technologies to acquaint themselves with the bands of operation authorised for amateur radio activities and the other conditions of operation provided for by the Radiocommunications Licence Conditions (Amateur Licence) Determination. AR readers can view or download a copy from the ACA's website.

Under the determination, spectrum immediately below 2.4 GHz is not available for amateur use in Australia (the September article refers to the FCC Rules that support amateur use down to 2.39 GHz in the USA). In January 2000, the Minister for Communications, Information Technology and the Arts designated the band 2302 - 2400 MHz throughout Australia as part of the spectrum to be allocated by issuing spectrum licences. It is now licensed across most of the populated areas of this country to various organisations that currently use it mainly for the delivery of pay-TV services.

The spectrum between 2.4 and 2.45 GHz can be used by amateur radio operators under the determination. It is part of a larger band of spectrum beginning at 2.4 GHz and extending in many cases up to 2.4835 GHz that is used also for many short-range applications. These applications include cordless telephones, radio LANs and various other computer peripherals, video-audio senders, barcode readers, wireless projection systems and video surveillance equipment. The ACA's radiocommunications class licences for low interference potential devices and for spread spectrum devices authorise anyone in this country to operate these types of devices, provided the devices are operated within the technical conditions of the relevant licence. Readers can view or download copies of these class licences from the ACA's website.

In recent years, this band has become very popular for short-range applications, which must rely mainly on the use of low radiated power (as specified in the class licences) to reduce the likelihood that they will cause radio interfere to each other - they are operated without individual frequency coordination or registering of location.

I note that under the determination, amateur radio operators may transmit in this band at much higher power levels, so the risk of amateur operations causing interference to the other users of the band is increased. The ACA encourages the amateur radio community to conduct any higher powered experiments in this band with a sense of goodwill towards the many users of low powered devices, so that all parties can continue to share this popular band of spectrum.

Yours sincerely,
Len Bray
Deputy Manager
Spectrum Planning Team
Radiofrequency Planning Group
8 December 2003

QNEWS 2003

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UWB

Ultra Wide Band (UWB)

Designed for short-range wireless connection of multiple devices for transmission of audio,
video and other high-bandwidth data. It is used to relay data from a host device to multiple
other devices in the surrounding area up to 10 meters.

Wireless USB devices are expected be the first to use this technology in consumer equipment.

The technology

UWB is defined as any radio technology having a spectrum that occupies a bandwidth greater
than 20 percent of the centre frequency, or a bandwidth of at least 500 MHz.
UWB operates in the range from 3.1 GHz up to 10.6 GHz in the USA (July 2006)
Basically a UWB transmitter works by sending billions of very low power pulses across a very wide
frequency range with a bandwidth of several GHz.
Common UWB systems use Orthogonal Frequency Division Multiplexing (OFDM) and other modulation
techniques over multiple bands.
The combination of very high bandwidth and low power limits the interference to other uses of
the frequency range.

Further information:-

uwb forum

DEVICEFORGE.COM

 

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