169 MHz ISM band antennas - a reality check!

The introduction of the EU harmonized ISM band at 169 MHz offers utility businesses a viable alternative to higher frequencies for wireless metering. Using the 169 MHz VHF frequency band, wireless metering can be deployed for longer range applications at relatively low power. This has many advantages for operations and billing organisations.

The challenge however comes with specifying 169 MHz antennas to go with the wireless meters. There are already a number of ISM-band 169 MHz module vendors with released products on the market and I am sure there are many more in development. From a RF perspective the module is relatively straightforward, but to supply compact, discrete antennas is not as easy.

A wavelength at 169 MHz is approximately 1.8M in length and therein lies the problem, for even a 1/4 wave monopole would be half a metre in length once the antenna had been housed in a sheath and connectorized.

For metering applications in domestic environments, discrete, tamperproof antennas are desirable, but not only is making a very low profile 169 MHz hard to achieve, it would also need a large groundplane. This is not particularly achievable on a small-sized utility meter. The options really are to use 1/4 wave 169 MHz helical antenna either bulkhead mount with a RF connector or through-hole mount so the antenna cannot be unscrewed from the meter. Both options would be approximately 120mm in overall length and would ideally need a minimum groundplane size of 85mm x 85mm. This size of groundplane could be possible on most meters, but a larger groundplane required by lower profile antennas are just not going to be possible.

Here are two images of the 169 MHz Helical with SMA and the 169 MHz through-hole mount:

 

169 MHz helical with SMA-Male connector

169 MHz permanent mount with N-Female connector

For concentrator applications (where a number of remote meters communicate with a hub using VHF communications), a wall-mount 169 MHz antenna might come in useful. Designed for outdoor use, ideally these will be of fibreglass construcion to withstand the elements. Here below is an image of the 169 MHz wall-mount antenna:

 169 MHz fibreglass wall-mount omni with bracket

It is also important to be wary of very small 169 MHz antennas as invariably some parameter will be compromised, for example small 169 MHz PCB antennas with a gain of -17.6 dB. It is useful to remember that the laws of physics are not going to change and that the wavelength is always going to be 1.8M. Very small antennas are going to massively compromise RF performance, defeating the very object of the exercise.

In conclusion, the 169 MHz band is a real opportunity for wireless metering and related applications, however the antenna selection and design-in for the meter must be considered early and with the appropriate level of planning to ensure that a suitable antenna design can be accommodated by the meter in terms of available groundplane etc. without comprising performance or aesthetics.

Related links:

An offering of 169 MHz antennas can be found here:

https://www.ead-ltd.com/products/169-433-868-915-antennas

Selecting 4G antennas

Interestingly, selecting a 4G antenna in Europe is not going to be as straightforward as selecting a 3G antenna has been. Due to 4G services being offered on a variety of frequency bands, customers will need to be aware at what frequency their 4G service is operating and what frequencies their antenna supports. Broadly speaking, 3G operates at the 2100 MHz across the whole of Europe which has made antenna selection quite straightforward.

For example, quite a number of operators across Europe have licences to run 4G services between 2500-2700 MHz otherwise known as the 2600 MHz band (countries such as Austria, Denmark, Finland, Norway, Sweden for example).  Not many 2G/3G antennas operate at 2600 MHz meaning that new antennas are required for customers migrating to 2600 MHz 4G services and antenna manufacturers have to otpimise their antennas to cover 2G/3G/ and 4G in one antenna. Currently, 2600 MHz antenna options for SOHO (small office/home office) are quite limited though vendors are moving quickly to plug this gap.

Alternatively in the UK, Everything Everywhere (formerly Orange & T-Mobile) has been given the go ahead by Ofcom to offer 4G services at 1800 MHz. This means that current European 2G/3G antennas already support the required frequency band for this 4G service. So customers have a wide choice of antenna solutions available to them.

Other frequency bands being considered for European 4G services include 800 MHz whilst the USA has LTE services operating in the 700 MHz.

In conclusion, customers will need to be sure of their frequencies or purchase a very wideband antenna to facilitate operation of their devices with 4G antennas.

Images of cables assembled by EAD/SAS

Here are couple of marketing images of RG58 RF cables with SMA-Male and TNC assembled by EAD.

New images of the WCO Waterproof Compact Omni Antenna

Here are some new images of EAD's waterproof compact omni antenna the WCO.

Family shot including the original connectors in the family:

We have since added TNC-Male RA, RP-TNC RA, RP-SMA Straight and RP-SMA Right Angle.

Here is a new marketing shot of the WCO bracket mounted.

The WCO antenna can support Pentaband Cellular/GSM/3G frequencies, 2.4 GHz, 868 MHz or 915 MHz frequencies and there are options to mount on metal or non-metal surfaces.

We can also offer a 433 MHz groundplane dependent WCO to mount either on a wall bracket or on a groundplane.

For more information, please contact us.

Antennas for GPS repeaters

Ofcom has recently opted for light licensing approach on GPS repeaters to provide indoor coverage for GPS applications. Specialist Antennas has a range of high quality, low noise permanent mount GPS antennas to complement GPS repeater applications.

The application looks as follows:

For environments such as aircraft hangars, emergency services locations, underground garaging, GPS repeaters enable GPS devices to maintain a satellite lock and keep location-based applications running.

The most recent version of the Ofcom Statement on Authorisation Regime for GNSS Repeaters describes the following headlines:

·         Licence fee set at £75

·         Licence applies to any of the three frequency bands: 1164-1215MHz, 1215-1300MHz, 1559-1610MHz

·         Permit the inclusion of multiple installations for GNSS repeater radiating elements at one address provided they are set out on the licence

·         Allow GNSS repeater installations in defined fixed locations only (mobile use will not be authorised)

·         Only permit GNSS repeater use indoors (as defined in the licence)

·         Use the ETSI standard as the compliance assessment baseline for GNSS repeater devices manufactured or assembled from component parts.

·         Allow licences to be traded on an outright or concurrent basis (partial trades split geographically or by frequency will not be permitted)

·         Set an indefinite licence term and ensure we have an archive database of all sites that are or have been licensed

For more information about the licensing situation, it is worth taking a look at the latest news and article sections at www.gps-repeaters.com for more information.

WCO antennas now offer RP-TNC and TNC-Male connectors

EAD - www.ead-ltd.com - now offers its WCO (waterproof compact omni) antennas for Pentaband Cellular/GSM/3G or 2.4 GHz frequency bands with RP-TNC or TNC-Male connectors.

RP-TNC is commonly used for WLAN/WiFi applications. TNC-Male is often used on cellular terminals and routers.

For more information, please contact EAD.

Statement on Authorisation regime for GNSS repeaters

In a statement published on this date Ofcom sets out its conclusions on the proposal to implement a light licence regime to authorise the use of Global Navigation Satellite System (GNSS) repeaters in the UK.
As described in the earlier bulletin on 6 April 2012 (below) there is a need to keep track of the whereabouts of GPS repeater installations in case of any reported cases of wireless interference.
Initially it was thought that the license regime would be implemented in the September time-frame, but the latest estimate from Ofcom brings this forward to the end of July, once the relevant documentation is finalised and in place.
The official statement can be viewed here.
Our partner company Faltech offers a range of GNSS repeaters in the UK - www.gps-repeaters.com