36 Farming Ahead August 2007 No. 187 www.kondinin.com.au

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While glass-mounted antennae are convenient, they aremore suited to the city or areas with more reliablecoverage. The transmission of the signal through the glasscan lose up to 5dB. But the extra height of the externalantenna will result in a small amount of gain.

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R E S E A R C H : N E X T G P H O N E S F R O M T H E W O R K S H O P

As Kondinin Group tests reveal, phone receptionusing a Next G handset means connecting thephone to an external antenna is vital.

But not all phones have an external antenna jackwhere a patch lead can connect the handset to anantenna. Of all Next G phones available, only the I-mate Jasjam, LG TU500, LG TU550, and TelstraZTE 150 have antenna jacks.

Previously, using patch leads with some Next Gphones could void the manufacturer’s warranty.But this is no longer the case and the use of a patchlead to connect to an antenna is vital to improvereception. Inductive patch leads are inferior andgenerally do not work well.

In areas of marginal signal strength, an antennais essential to extend the phone’s reception andreduce call drop-outs.

Antenna selection is usually an afterthoughtwhen selecting a phone handset but in many casesinvesting in a quality antenna can be the differencein the ability to make calls in marginal signal areas.

Antennae do not increase the signal power of the phone but flatten it out. Higher gain antennaeincrease the flattening of the signal, generallyextending it further. This is perfect for large, flatand expansive areas but will also help in steep andhilly country.

Kondinin Group engineers tested compatiblehandsets with 3.5-decibel (dBi) and 6.5dBi antennae($30 and $120 respectively). Both provided improvedreception range but in flat areas during testing, the 6.5dBi (broomstick style) antenna providedsuperior range.

Smart antenna choiceboosts reception reliability

A magnetic base antenna is idealfor temporary situations where apermanently installed antenna isnot an option.

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Smaller antennae such as the 3.5dBi unit pictured can be installed in a vehicle’s window using an inductiveconnection. This allows the base with the antenna to befixed to the window and the pick-up, which is connected tothe cable, to be fixed to the inside of the window.

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If using a glass-mounted antenna, ensure the antenna isvertical and not slanted toward the rear for best reception.

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dB gain terminology Some dB ratings of antennae can be confusing with

manufacturers specifying gain in dB, dBi or dBd.

In most cases, simply dB will be specified, whichusually is interchanged for a dBi rating. If theantenna is specified as dBi, add 2.5dB to the dBirating to get an equivalent dBd rating.

What about car kits?Car kits specific to each handset used to be

commonplace, requiring an entire new kit or cradleto be purchased with every new handset.

Dedicated car kits with a cradle allow users tocharge the phone in the car, connect directly to an external antenna (if a connection is available)and hold the phone in place while driving.

Bluetooth connectivity, as available in all handsetstested, has changed car kits, allowing differenthandsets to be used with one wirelessly connectedcar kit provided it is a bluetooth handset (see Table 2,page 34). This means upgrading a phone no longermeans upgrading the car kit as well.

But there are drawbacks — if an external antennais required to improve coverage, it will still need tobe connected; and a power lead needs to beconnected for in-car phone charging.

Connection of both power and antenna to phonesusing bluetooth car kits could seem messy, sodedicated car kits in this instance would be preferred.

A cheaper option to improve reception is to installan antenna without a car kit and use the handset’sspeakerphone function while talking. The 3.5dBiantenna kit used in testing cost only $30 andincluded both magnetic and inductive (window)bases, long and stub antennae and cable.

Larger antennae such as the 6.5dBi unit pictured will providebetter reception but needs to be mounted securely to thevehicle. It is not generally possible to use a temporarymagnetic mount. The antenna pictured is mounted in anideal location on the headboard of a ute (see Figure 4).

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F R O M T H E W O R K S H O P N E X T G P H O N E S : R E S E A R C H

Bullbars provide a solid mounting point for anantenna and are often better protected from hittingoverhead branches as the driver can see the antennathrough the windscreen. But there is less receptionthan for a roof-mounted unit (see Figure 4).

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A $15 stainless steel bracket avoids having to welda bracket to the bulbar or headboard.

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Other brackets for larger antennae are available formounting antennae to the side of the boot orbonnet (pictured) of a car. Brackets are designed toextend through the crack between the bonnet orboot when closed.

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Install the cable behind trims or under floor mats. If the vehicle is traded regularly, ensure the cablecan be removed easily.

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Connect an appropriate patch lead to the other endof the cable. Patch leads (inset) cost about $20 andare used to connect the phone handset to theantenna cable. If the cable is overly long it couldaffect reception, so it pays to trim it and have a newplug crimped on.

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A 12-volt power adapter can be added so thehandset does not run off its internal battery.Adapters cost $30–$50.

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FIGURE 4 Where to position antennae for best signal reception

Mount antennae where they are least likely to have signal blockages. Source: Kondinin Group.

37Farming Ahead August 2007 No. 187 www.kondinin.com.au

While most handsets have a speakerphonefunction, a bluetooth hands-free device makesreceiving and sending calls even easier. The devicehas both a speaker and microphone and calls areanswered by pressing a button on the unit. Other versions have phone buttons that enabledialling from the unit. It costs about $130 and is connected wirelessly to the handset usingbluetooth communications protocols.

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Even with ahandset notconnected to anexternal antenna,there are severalways to improvereception inmarginal areas.

If travelling in acar without a car kitor antenna, stop thevehicle and standoutside. There oftenwill be an increasein reception outsidea vehicle compared with sitting inside a moving car.

If the location ofthe nearest phone tower is known, pointthe phone toward the tower so the person’shead is not between the phone and thetower. By moving around slightly, receptionoften can be improved.

As the internal antenna in many phonehandsets can be covered by a hand whentalking, use fingers to hold the phone (aspictured). If the handset is fitted with a pull-up antenna, ensure it is fully extended.

Improving reception

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Cables often can be run behind door seals as shownbut it is best avoided if it tends to pop out.

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