Has it got a short on the ariel where the outer touches the inner ?
Conor:
Bking:
The aerial has to be earthed to the frame(negative side of the supply) to transmit the signal.No it doesn’t.
Conor,
I’m a bit thick when it comes to electrics, so could you explain how this works without an earth please?
If both trucks are parked quite close you should be able to hear each other without even having an aerial plugged in, say within 100ft that is, aerial does not need to be earthed to truck chassis, but may work better over longer distance and get less interference if you do earth the mag mount to the truck chassis.
Is the mike matched to the cb because cybernet wont work in a uniden cb, there are at least 3 different wiring options for mikes, swr wont matter over short distance either and i doubt you can get in down to much below 1:5 anyway because you twig is probably hidden behind an airkit, so your signal cannot get out very well anyway !
dieseldave:
Conor:
Bking:
The aerial has to be earthed to the frame(negative side of the supply) to transmit the signal.No it doesn’t.
Conor,
I’m a bit thick when it comes to electrics, so could you explain how this works without an earth please?
Basically, AC theory. It can work without being able to flow to ground because being AC, as the voltage rises and falls, a current still flows and what it will do is work against a “floating” ground. An example is if you disconnect the “negative wire” of a light socket and turn the light on, the bulb will still glow but far less brightly. It gets complicated.
When the transmitter drives electrons onto one wire of a dipole antenna (creating a surplus of charges), it draws electrons from the other wire (creating an absence of electrons). The electric field runs then from the absence of electrons on one wire to the excess of electrons on the other. This flow of electrons surges back and forth at the frequency of the signal being transmitted. The surging electrons are the current in the antenna wire. So in a dipole, all currents and voltages are flowing wholly within the antenna and do not return to “DC ground”.
When we use an antenna that is essentially only one wire such as a mobile antenna or a vertical antenna, the transmitter drives electrons into that wire while drawing electrons from whatever other conductor is connected to the return line to the transmitter. There must be a conductor which the transmitter impresses electrons and another from which it draws electrons. In an mobile antenna, this ideally is the body of the car. Basically the vehicle makes up the “missing half” of a dipole antenna. If the vehicle body isn’t sufficient it then starts to use the outer of the coax trying to find the easiest path back to source.
If we were to use a mobile antenna without it being on a vehicle - say sat on a big block of wood - it would still transmit a signal but would use the co-ax shield to make up the missing half of the antenna instead of the vehicle body. How strong the signal is would depend on the length of coax. You would have RF flowing on the coax and if you used enough power you would get RF burns if you touched the coax and you most likely will get distorted audio from the RF flowing through the rig, the mic cable and causing interference.
When it comes to installing mobile antennas, it is the metal under the antenna that counts, not what is alongside it. That is why mirror mounts and magmounts put on the backs of cabs are absolutely diabolical. To give you an example, a mate of mine had his mounted on the back of his Iveco with a magmount. With 100W he could only do 10 miles or so. With my Sirio in the middle of the roof of my car I could do 20 miles very easily with just 5W. Also when it comes to antenna performance it is reciprocal so anything affecting transmit also affects receive. So if its mounting position and method affects its transmitting range, it’ll also mean it won’t receive as well either.
Conor:
dieseldave:
Conor:
Bking:
The aerial has to be earthed to the frame(negative side of the supply) to transmit the signal.No it doesn’t.
Conor,
I’m a bit thick when it comes to electrics, so could you explain how this works without an earth please?
Basically, AC theory. It can work without being able to flow to ground because being AC, as the voltage rises and falls, a current still flows and what it will do is work against a “floating” ground. An example is if you disconnect the “negative wire” of a light socket and turn the light on, the bulb will still glow but far less brightly. It gets complicated.
When the transmitter drives electrons onto one wire of a dipole antenna (creating a surplus of charges), it draws electrons from the other wire (creating an absence of electrons). The electric field runs then from the absence of electrons on one wire to the excess of electrons on the other. This flow of electrons surges back and forth at the frequency of the signal being transmitted. The surging electrons are the current in the antenna wire. So in a dipole, all currents and voltages are flowing wholly within the antenna and do not return to “DC ground”.
When we use an antenna that is essentially only one wire such as a mobile antenna or a vertical antenna, the transmitter drives electrons into that wire while drawing electrons from whatever other conductor is connected to the return line to the transmitter. There must be a conductor which the transmitter impresses electrons and another from which it draws electrons. In an mobile antenna, this ideally is the body of the car. Basically the vehicle makes up the “missing half” of a dipole antenna. If the vehicle body isn’t sufficient it then starts to use the outer of the coax trying to find the easiest path back to source.
If we were to use a mobile antenna without it being on a vehicle - say sat on a big block of wood - it would still transmit a signal but would use the co-ax shield to make up the missing half of the antenna instead of the vehicle body. How strong the signal is would depend on the length of coax. You would have RF flowing on the coax and if you used enough power you would get RF burns if you touched the coax and you most likely will get distorted audio from the RF flowing through the rig, the mic cable and causing interference.
When it comes to installing mobile antennas, it is the metal under the antenna that counts, not what is alongside it. That is why mirror mounts and magmounts put on the backs of cabs are absolutely diabolical. To give you an example, a mate of mine had his mounted on the back of his Iveco with a magmount. With 100W he could only do 10 miles or so. With my Sirio in the middle of the roof of my car I could do 20 miles very easily with just 5W. Also when it comes to antenna performance it is reciprocal so anything affecting transmit also affects receive. So if its mounting position and method affects its transmitting range, it’ll also mean it won’t receive as well either.
Very well explained 
So could you attach a wire to the cb and then to an earthing point in the cab or would you run it to where you antenna is ?
Conor,
no mention a the ‘ground plane’ effect in the post you copied off the web somewhere. A flat metal surface at 90 degrees to the aerial (like the roof of your car) will increase the transmitting range as it works like a reflector so the vertical back of a truck and the vertically mounted aerial on a magmount will have the opposite effect. Wind deflectors are usually made of fibre glass and as such will have no effect on your signal getting out a fair way.
PS. make sure the twig is clean otherwise the signal wont get out thru the dirt 
Conor:
dieseldave:
Conor:
Bking:
The aerial has to be earthed to the frame(negative side of the supply) to transmit the signal.No it doesn’t.
Conor,
I’m a bit thick when it comes to electrics, so could you explain how this works without an earth please?
Basically, AC theory. It can work without being able to flow to ground because being AC, as the voltage rises and falls, a current still flows and what it will do is work against a “floating” ground. An example is if you disconnect the “negative wire” of a light socket and turn the light on, the bulb will still glow but far less brightly. It gets complicated.
When the transmitter drives electrons onto one wire of a dipole antenna (creating a surplus of charges), it draws electrons from the other wire (creating an absence of electrons). The electric field runs then from the absence of electrons on one wire to the excess of electrons on the other. This flow of electrons surges back and forth at the frequency of the signal being transmitted. The surging electrons are the current in the antenna wire. So in a dipole, all currents and voltages are flowing wholly within the antenna and do not return to “DC ground”.
When we use an antenna that is essentially only one wire such as a mobile antenna or a vertical antenna, the transmitter drives electrons into that wire while drawing electrons from whatever other conductor is connected to the return line to the transmitter. There must be a conductor which the transmitter impresses electrons and another from which it draws electrons. In an mobile antenna, this ideally is the body of the car. Basically the vehicle makes up the “missing half” of a dipole antenna. If the vehicle body isn’t sufficient it then starts to use the outer of the coax trying to find the easiest path back to source.
If we were to use a mobile antenna without it being on a vehicle - say sat on a big block of wood - it would still transmit a signal but would use the co-ax shield to make up the missing half of the antenna instead of the vehicle body. How strong the signal is would depend on the length of coax. You would have RF flowing on the coax and if you used enough power you would get RF burns if you touched the coax and you most likely will get distorted audio from the RF flowing through the rig, the mic cable and causing interference.
When it comes to installing mobile antennas, it is the metal under the antenna that counts, not what is alongside it. That is why mirror mounts and magmounts put on the backs of cabs are absolutely diabolical. To give you an example, a mate of mine had his mounted on the back of his Iveco with a magmount. With 100W he could only do 10 miles or so. With my Sirio in the middle of the roof of my car I could do 20 miles very easily with just 5W. Also when it comes to antenna performance it is reciprocal so anything affecting transmit also affects receive. So if its mounting position and method affects its transmitting range, it’ll also mean it won’t receive as well either.
Conor,
Thanks for that, I’ve learned something. 
I I’ve just put a cb in a 62 plate fm13 which came fitted with aerial but no power plug.Alli done is run som2 core cable along top and down passenger side and wired to a power source I found and cb worked straight away and talked to some one 1.5miles away while I was parked in she’d and I was blasting out .It is a 12/24v cb
Has anyone tried using an artificial ground plane like this one?
4x4cb.com/public/item.cfm?itemID=972
If you have what were the results like?
blower driver:
I I’ve just put a cb in a 62 plate fm13 which came fitted with aerial but no power plug.Alli done is run som2 core cable along top and down passenger side and wired to a power source I found and cb worked straight away and talked to some one 1.5miles away while I was parked in she’d and I was blasting out .It is a 12/24v cb
Behind 1 of the 2 false panels nr the tacho is the coax from the ariel, its taped on the back of the false panel, i just rammed a plug on the end of that, wired my 12/24volt cb in, plugged ariel in and it works great