Mud-club
Vehicle & Technical => Discovery => Topic started by: thermidorthelobster on February 06, 2005, 20:56:04
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I was in Widecombe-in-the-Moor car park earlier and spotted a lifted grey Y-reg Disco II running very mud-oriented tyres (can't remember which ones now, but they were 235/70s), with a snorkel, Safety Devices roof rack, Safari snorkel, hefty spotlights, plus 2 CB aerials.
It looked good, the wiring for the aerials / spots was very neat, although there were suspiciously few scratches on the paintwork :wink:
Was it anybody here?
And why 2 aerials? :?
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If I remember this right. :oops: You use two cb arials so the signal goes futher ahead and behind and less to the side. 8) Think thats why lorrys use two.
Hope this helps.
Rich
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i thought they used two aerials for two different radio sets?
if not and they do use two then how would it affect snr etc?
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You can use two antennae in parallel to modify the radiation pattern of the your set-up, providing a more 'directional' system.
In most respects, for a mobile set up, I reckon a single antenna is better as you (tend to) get a more uniform radiation pattern giving a better signal in all directions.
In addition, I can't remember off the top of my head what the licence restrictions are on antennae for CB.
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ah right i see
makes sense
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You can use twin twigs...........it is the wave length of the twig which must remain at 5/8ths I think.........
twin twigs on a truck alter the radio output to a better front & rear signal, After all when you are on the motorway you want to talk the wagons in front or behind you not to some turkey on a housing estate...... :lol:
Anyway some bright spark is likely to appear and correct us...... :lol: :D
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Is the directional gain in line with the aerials, or at right angles to them?
The Widecombe Disco had one on the left, one on the right.
D
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Said smart arse duly appears: :wink:
It all depends on seperation distance, across a truck cab/landie the pattern will bias front rear, further apart (don't remember the figures) in line. The biggest problem is co-phasing needs the correct harness (75ohm cables matched lengths connected to 50 ohm to the rig) to work properly. Of course it might have had cb and ham rigs....
Niel. :D
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As I said....................Await the smart arse..............and one shows up........ :lol: :lol: :lol:
Cheers Niel