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Re: UHF radio
Originally Posted by jazzys
(Post 6099220)
If i got one of these units would i have to get another aerial fitted to my car.
Possibly one of these big daft things you sometimes see on 4 x 4's? Jazzys Radio, light, sound and other waves all have similar properties. The aerial needs to be tuned just like a musical instrument. A car UHF has to be capable of working on a band of frequencies so there have to be compromises, however for the UHF bands the length of the aerial will be measured in centimetres, possibly around 17.5 or less, could even be half this to achieve optimum resonance. I've often thought about those "big daft things you sometimes see on 4 x 4's", it might be that they are using a band just below the AM broadcast band, that would be ideal for long range communication in Australia. The alternative is that someone is making a lot of money selling a huge fibre glass aerial with a tiny metal aerial hidden in it. Aerials are such a complex subject that many very thick hard back books have been published on the subject. The most effective aerial is one that achieves resonance on the frequency used. They also have to be sited well, a motor vehicle makes a good base, the best place is dead centre of the roof but not many people like to drill holes in that part of the car, there's also the problem of getting the wires to them. Some emergency service vehicles have their aerials mounted on roof racks, the second best place. |
Re: UHF radio
Originally Posted by jazzys
(Post 6099220)
If i got one of these units would i have to get another aerial fitted to my car.
Possibly one of these big daft things you sometimes see on 4 x 4's? Jazzys The best place to site an antenna on a vehicle is directly in the centre of the roof. That does not suit all as you will have to drill a hole to mount the antenna. With 5 watts of power, you are only really going to get approx 6 to 10 Kms of range in clear country without going through a repeater. Barney:thumbup: |
Re: UHF radio
I can't add any more to this thread cos its way over my head. I just know that i'd like to have a bit of kit that would allow me to find out where those sneaky coppers are hiding behind bushes. And if possible i'd like it to cause as little damage to my car as possible, by way of having to drill holes in parts of my bodywork.
Jazzys |
Re: UHF radio
Originally Posted by NigelWaring
(Post 6101422)
It's a very complicated subject, aerials was one year of a three years radio course that I completed about 50 years ago, the theory hasn't changed.
Radio, light, sound and other waves all have similar properties. The aerial needs to be tuned just like a musical instrument. A car UHF has to be capable of working on a band of frequencies so there have to be compromises, however for the UHF bands the length of the aerial will be measured in centimetres, possibly around 17.5 or less, could even be half this to achieve optimum resonance. I've often thought about those "big daft things you sometimes see on 4 x 4's", it might be that they are using a band just below the AM broadcast band, that would be ideal for long range communication in Australia. The alternative is that someone is making a lot of money selling a huge fibre glass aerial with a tiny metal aerial hidden in it. Aerials are such a complex subject that many very thick hard back books have been published on the subject. The most effective aerial is one that achieves resonance on the frequency used. They also have to be sited well, a motor vehicle makes a good base, the best place is dead centre of the roof but not many people like to drill holes in that part of the car, there's also the problem of getting the wires to them. Some emergency service vehicles have their aerials mounted on roof racks, the second best place. gets complicated dosnt it jazz http://www.roity.com/rc/airwaves.html |
Re: UHF radio
Originally Posted by steve`o
(Post 6101552)
Jazzys :p |
Re: UHF radio
Originally Posted by jazzys
(Post 6101447)
I can't add any more to this thread cos its way over my head. I just know that i'd like to have a bit of kit that would allow me to find out where those sneaky coppers are hiding behind bushes. And if possible i'd like it to cause as little damage to my car as possible, by way of having to drill holes in parts of my bodywork.
Jazzys If it's to much for you just pull into a TJM or an Autobarn & pay for the whole package including fitting circa $500 bucks for a basic setup. Thats about three speeding tickets & nine points worth. |
Re: UHF radio
Originally Posted by cresta57
(Post 6103006)
It doesn't have to be complicated a simple mag mount would suffice or a gutter mount or a trunk mount or a bonnet mount all will give you sufficient distance to communicate with other users on the highway & no need for drilling holes anywhere.
If it's to much for you just pull into a TJM or an Autobarn & pay for the whole package including fitting circa $500 bucks for a basic setup. Thats about three speeding tickets & nine points worth. Whats TJM? Jazzys |
Re: UHF radio
Originally Posted by jazzys
(Post 6103012)
Well i'm already on my second so that makes it $700 :D
Whats TJM? Jazzys |
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