RADIO SALES, SERVICING, CONSULTANCY, DESIGN

Satphones, Commercial, Amateur, CB, GPS, Marine Radio and Surveys

Shop/Office: 243 Seacombe Road, South Brighton, South Australia 5048

Postal: PO Box167, Brighton, South Australia, 5048

Shop Hours: Mon- Fri 9am-5:30pm Sat 9am-5pm

Tel/Fax: 08 8298 3906     International +61 8 8298 3906

Email: mail@radiospecialists.com.au

ABN:20 428 966 535

Huge range of antennas:  UHF, 27MHz, commercial, broadcast, marine, cell phone, amateur. 

Huge range of brands: Scalar, GME, RFI, Benelec, Axis, Comet, Laser, Uniden. 

On-glass UHF: loads of inquiries for on-glass for 4WD and modern vehicles without gutters, so we are well stocked 

ANTENNA GAIN

With low antenna gain the radiation pattern is essentially a donut shape of energy around the antenna. Shown here is a vertical antenna and cross section of the donut at 3dB gain. As more sections are added to the antenna the donut becomes flattened. The same amount of transmitter power is being fed into the antenna and the result is that the energy is radiated further (6dB gain antenna). More antenna sections increase the gain more and flatten the radiation pattern into a disk (9dB gain antenna).

What is dB? A decibel (dB) is an engineering convenience for expressing power ratios. It is 10 log P1/P2. 10 log 2/1 = 3 dB. In other words every time you have an equivalent of double the power you add 3 dB. So your 3dB antenna is the equivalent of having a transmitter with twice the power, and 6 dB is the equivalent of 4 times the power. 9dB is the equivalent of 8 times the transmitter power. 12dB is the equivalent of 16 times the transmitter power (6dB + 6dB is the same as 4 x 4 = 16 times !) 

So how much gain is good ? It depends what you are trying to do. For base station antennas high gain is good. For vehicles a gain of around 4.5dB is usually the best.

dBd means dB relative to a dipole.  

dBi means dB relative to an isotropic radiator (point source, theoretical).

1 dBd = 2.15dBi. 

Some manufacturers quote antenna gain in dB which is meaningless. 

It has to be dB relative to something, a dipole (dBd) or isotropic (dBi).

VEHICLE RADIATION PATTERNS

Too much antenna gain results in the energy being directed towards the sky or down into the ground, when the vehicle is in hilly terrain. A lower gain antenna will capture the antenna of the other vehicle in hilly terrain.

Some of our customers buy two antennas and a changeover switch. One long range antenna and one short range for sand dunes. 

NA-771/477 for handhelds

$20.40

NA771/477

Designed for the Australian UHF frequency band.

Gain antenna for handheld radios eg Vertex VX-426

Flexible type.

NL-350/477

$23.30

NL-350/477

Designed for the Australian UHF frequency band.

Stubby antenna for roof mount 220mm long 

NL-RS/477

$26.40

NL-R2/477

Designed for the Australian UHF frequency band.

Stubby antenna for roof mount, magnetic bases etc.

Flexible type.

Ground plane independent.

NL-88S/477

$26.40

NL-88S/477

Designed for the Australian UHF frequency band.

Stubby antenna for roof mount, magnetic bases etc.

Ground plane independent

Commercial grade quality. Ideal for country use.

Expect to pay twice this for similar items. Add the antenna below for city.

$59.95 value item. The best.

Complete kit with 5 metres of the best low loss double shield cable.

Loss is approx 1dB only at 477 MHz.PL259 plug and SO239 mount.

$79.90 The best.

TQC-400FI-477

Designed for the Australian UHF frequency bands for Radio Specialists. 

Centre frequencies of 477 MHz and 440 MHz (others available for commercial users). Ground plane independent.

Made from stainless steel and comes complete with a spring. These antennas have a slender upper section and thicker lower section which makes them very sturdy and at the same time allows the antenna to flex considerably and hence are suitable for 4WD off road use. Inside the spring is braid hence the flexing of the spring will not detune the antenna. Bull bar mount or roof mount. 

This antenna will suit most applications requiring medium gain as described above.

AE4705 477 MHz 4.5dB bull bar style antenna

1200mm long. Our top seller. $ in-store

AE4705

AE4706 Same style as above but 2100 mm long. $ in-store.

AE4706

The big ones.  Always in stock in the shop. 6dB gain and 2.1m long. Buy this one and also the smaller whip to go with it, the AW4702 4dB 1m long for around town.

Window clip and UHF 477 MHz antenna 

Nifty idea for travellers who don't want to use magnetic bases

Good SWR tested with this combination.

Use it with your handheld UHF or your in-car UHF.

Complete kit with 2.75m (9 ft) of cable. $59.95

WCLIP477

UHF CB frequency 477 MHz.

Ground plane independent.

Great idea for travellers, hire cars etc.

Pop it in your suitcase on your next flight.

Top  grade, quality item 950mm high

Stock item. The spring is included at this price!

$119.95 value item. 

CL474COMBI

Designed for the Australian UHF frequency bands this is a quality Australian made antenna for those who like the white sticks on the bull bar. Very competitive price.

Centre frequency of 477 MHz and ground independent. Suitable for 4WD off road use. Inside the spring is braid hence the flexing of the spring will not detune the antenna. 

Top  grade, quality item 1130mm high

Stock item. The spring is included at this price!

$139.95 value item. 

CP474S

Designed for the Australian UHF frequency bands this is a quality Australian made antenna for those who like the white sticks on the bull bar. Very competitive price.

Centre frequency of 477 MHz and ground independent. Suitable for 4WD off road use. Inside the spring is braid hence the flexing of the spring will not detune the antenna. 

Top  grade, quality item 1630mm

Stock item. The spring is included at this price!

$149.95 value item. 

CP476S

Designed for the Australian UHF frequency bands this is a quality Australian made antenna for those who like the white sticks on the bull bar. Very competitive price.

Centre frequency of 477 MHz and ground independent. Suitable for 4WD off road use. Inside the spring is braid hence the flexing of the spring will not detune the antenna. This is a high  gain antenna and you will get a good signa out.

Commercial grade quality

Expect to pay twice this for similar items

Add this to the above antenna for city use

$19.95 value item. The best.

TQC-400BII

Designed for the Australian UHF frequency bands for Radio Specialists. 

Centre frequencies of 477 MHz and 440 MHz (others available for commercial users). 5/8 wave element. Ground plane required.

Made from stainless steel and comes complete with a spring. These antennas have a slender whip for low wind noise and they are very sturdy. Suitable for 4WD off road use. Inside the spring is braid hence the flexing of the spring will not detune the antenna. Roof mount (or bull bar short range).