stuck Posted April 1, 2009 Share Posted April 1, 2009 Hi all, Forgive me if this is too but I want to fit a CB radio to my truck but know bugger all about them. Question is does the location of the antenna compensate for it's length? In other words will a short antenna mounted up high perform better than the same length antenna mounted lower down? Many thanks, Mick. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted April 1, 2009 Share Posted April 1, 2009 no. antennas should be cut to a proper length. much like a string on a guitar. If you said I want a note but cant be bothered to tune it it would sound like a bad celine dion meets meatloaf concert. The position of the antenna will however help pick up weak signals better. As will siting it over a large earthed metalic object such as the centre of a metal roof. Albeit that your truck isn't that well earthed. Sods law dictates though the higher the antenna is mounted the more it will be attacked by trees/bridges/kids and the temptation to hang flags/gonks off it for no apparent reason Pete Quote Link to comment Share on other sites More sharing options...
cooney? Posted April 1, 2009 Share Posted April 1, 2009 i'm no expert but someone said once that there an idea antenna lenght for what frequency you trying to transmit or recive so i thik they must be made in that size for the frequency your useing. probally no help at all that Quote Link to comment Share on other sites More sharing options...
cooney? Posted April 1, 2009 Share Posted April 1, 2009 i'm no expert but someone said once that there an idea antenna lenght for what frequency you trying to transmit or recive so i thik they must be made in that size for the frequency your useing. probally no help at all that Quote Link to comment Share on other sites More sharing options...
western Posted April 1, 2009 Share Posted April 1, 2009 the antenna is tuned to a wavelength to suit the frequency it [antenna] is required to operate on. have a look at the tech archive index for the CB SWR info. Quote Link to comment Share on other sites More sharing options...
stuck Posted April 1, 2009 Author Share Posted April 1, 2009 Cheers Gents. Whilst we are on the subject can anybody explain squeltch to me? Mick. Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 1, 2009 Share Posted April 1, 2009 Question is does the location of the antenna compensate for it's length? In other words will a short antenna mounted up high perform better than the same length antenna mounted lower down? Being an ex Avionics Engineer in the RAF, I did a small bit regarding communications and from what I can remember the length of an antenna determines the range of frequencies it can receive/transmit You can read some CB stuff from here and here. Having an antenna mounted low down will affect it's ability to provide enough range, up is best. Oh, being whipped in the face by a low down one, hurts. I've got one of these and I can pick up traffic from a long way off further away than those I'm out-n-about with. Most importantly, you need a good earth "Ground Plane" or the CB set wont last long. On Land & Range Rovers, when the aluminium is exposed to air, a chemical reaction called oxidisation starts to happen. Over a relatively short period of time this can introduce a resistance to the earth connection. Without prevention, the connection is soon lost, and your aerial is trying to work without a ground plane, with a very noticeable deterioration in performance (and the risk of damage to the set). One method you could use is to run a short earth strap (heavy gauge speaker cable will do) from the bottom of the mount to a point on the chassis or elsewhere on the vehicle. Hope this helps, Keith. Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 1, 2009 Share Posted April 1, 2009 Cheers Gents.Whilst we are on the subject can anybody explain squeltch to me? Mick. When there is nobody transmitting on a channel all you hear is noise, to get rid of this noise you increase the squelch until it has cut off. However, you will still receive all other stations. If you turn up the squelch even more, distant stations will also be cut out, if you turn it up to maximum only very strong or local stations will be heard. Quote Link to comment Share on other sites More sharing options...
stuck Posted April 1, 2009 Author Share Posted April 1, 2009 When there is nobody transmitting on a channel all you hear is noise, to get rid of this noise you increase the squelch until it has cut off. However, you will still receive all other stations. If you turn up the squelch even more, distant stations will also be cut out, if you turn it up to maximum only very strong or local stations will be heard. Thanks very much for the tutorial Keith,Much appreciated. Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 1, 2009 Share Posted April 1, 2009 Thanks very much for the tutorial Keith,Much appreciated. No probs, Mick. Quote Link to comment Share on other sites More sharing options...
disco tony Posted April 1, 2009 Share Posted April 1, 2009 Whilst we are on the subject can anybody explain squeltch to me? Mick. Its when you think your antennae has been ripped off the roof, you jump out quick and.............SQUELCH, bluddy cowpat! It seems to eliminate background noises, but the more you turn it down, the more of what you want to her goes, not very technical Ted, but in a nutshell. Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 1, 2009 Share Posted April 1, 2009 Forgive me if this is too but I want to fit a CB radio to my truck but know bugger all about them. Just found this simple info about CB's Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 1, 2009 Share Posted April 1, 2009 Install ideas 4 ya. I've mounted my antenna up on the rack - top right. Ground Plane is done via the rack - centre left. CB is also up there. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted April 2, 2009 Share Posted April 2, 2009 alfaman like the roof lights front and rear, any details. are they led? Quote Link to comment Share on other sites More sharing options...
SteveG Posted April 2, 2009 Share Posted April 2, 2009 alfaman like the roof lights front and rear, any details. are they led? what the halogen bulbs in plastic ducting? ;) Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 2, 2009 Share Posted April 2, 2009 what the halogen bulbs in plastic ducting? ;) Yep, precisely that they are, up front. 35W max or the plastic gets a bit soft LED's used on the back. You can get 35W Halogens that give the light output of a 50W, think Phillips make them. Started as a test, trial, mock-up idea I had after seeing the X-Eng ones, I don't have a roll cage. Oh, they do work very well, 4 point forward and 2 point out @ 45°, perfect for spotting what the next potential road-side menu is going to be, or not. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted April 3, 2009 Share Posted April 3, 2009 Yes I was wondering if things got a bit warm using the upvc, nice way of mounting and sealing them though. I guess if you are using push fit pipe you can change bulbs easy enough. I don't s'pose leds are quite there yet for light output. Pete Quote Link to comment Share on other sites More sharing options...
alfaman Posted April 3, 2009 Share Posted April 3, 2009 I don't s'pose leds are quite there yet for light output. Not sure but I think so, have a look at these. Not got any yet, but will, soon. Quote Link to comment Share on other sites More sharing options...
SteveG Posted April 3, 2009 Share Posted April 3, 2009 These LED lights are waterproof and each LED pumps out 800 lumens LED's Quote Link to comment Share on other sites More sharing options...
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