UHF Aerials

[Walker]

What is the difference (if any) between the small skinny metal or fibreglass aerial and the thicker white fibreglass aerial?

I was looking at GME aerials and they were both earth independent and were both 4.5db on elevated spring bases.

I am guess that they are both similar but the skinny one is more flexible. I was just wondering what the advantage of the thick white aerial is?

[Wal]

What is the difference (if any) between the small skinny metal or fibreglass aerial and the thicker white fibreglass aerial?

I was looking at GME aerials and they were both earth independent and were both 4.5db on elevated spring bases.

I am guess that they are both similar but the skinny one is more flexible. I was just wondering what the advantage of the thick white aerial is?

Your aerial is the most important part of your UHF system and should be chosen carefully. The dB rating gives you the best idea of this. 3dB is the lowest and works well over short distances and in built up areas. 9 dB is the largest rating I've seen and can work over flat ground for a long way but any obstructions (trees, hilly terrain, etc) can seriously affect it. I went middle of the road and purchased a GME AE409L aerial - it's one of those thin silver ones you mentioned and I used the 6dB whip. I can take the 6dB whip off the base and substitute it with a 9dB whip but have yet to do so as this aerial has performed well in all conditions - including the dunes of the Simpson.

The thick white ones do the job quite well but I can't see them exceeding what I've got from my TX3400/AE409L combo. They can break very easily in certain situations. If you're using your UHF in the bush and around town then you need an aerial that's either 4.5 or 6 dB. And to complicate matters even further, where you mount it also makes a difference. Try this site from GME for further info

http://www.gme.net.au/land/antennas/choose_antenna.php

[mongoose]

I have cd5000 antenna made by RFI and it is brilliant at 5db gain I get about 12 - 14 km range in very slight hilly country. The thick white antennas as Wal said do break easily and then they dont work at all also they are very expensive. The main thing is that you need to have a ground plane independant antenna. The wire type antennas are good because you can remove them.
Try this link http://www.rfi.com.au/downloads/wire...MHz/CD5000.pdf

Hope this helps
Adrian
p.s. I got mine from prestige communications for $109.00 and they do free shipping.

[Walker]

Thanks all.

I ended up getting a GME 4.5db thin wire aerial. I will see how it goes and I checked and I can buy a 6 or 9db aerial to screw onto the same extended base for when I do outback trips.

[gp339gm339]

Antenna slection is based on where you are using the vehicle and what range you require.

The higher the gain, the flatter the radiation pattern ( Also narrow bandwidth). High gain anteenas are great for use in flat terain, but can casue problems in very hilly terain

I use a RFI 3 db GPI antenna that is flexable ( it bends over if a branch hitsand get good coverage in hilly terain.

Note, The anteanna ain is referrerance back to a quater wave mounted in the middle of the roof of a vehicle. (A quater wave is considered to have unity gain)

The biggest problem I see is people using crappy connectors on there expensive high gain antennas. (Never use the ones from Dick smith where the cable twists into the back of the connector, and have a screw for holding the centre conductorz))