CB Radios help

[spautoparts]

Thought id install a cb to my truck and bought this aerial. just wanted to know wheres the best place to put it.
im thinking of putting it on the roof rail, but does it need contact directly to metal for a good reception.:nenau im a complete novice with these things.
cheers in advance:thumb2

 

[briggie]

it needs to be fixed to a metal surface for grounding ...... check the swr too :thumb2

 

[spautoparts]

it needs to be fixed to a metal surface for grounding ...... check the swr too :thumb2

SWR?? please be patient with me, i aint got a clue.

 

[kwondo]

standardl wave ratio i think

 

[spautoparts]

so i take it its not like putting a new cd player in the car.... plug and play:doh

 

[rustic]

SWR?? please be patient with me, i aint got a clue.

Standing Wave Ratio.

This is an indication of how much power is reflected back, idealy it should be 1.0 which means ALL the power is radiated.
SWR over 1.5 means some power is reflected back into the transmitter, and if the SWR is much higher say over 2 then damage can be caused to the transmitter.

Without a meter, you won't know what the SWR is.
To improve the SWR, moving the aerial might be enough, or changing the length of the aerial by say 5 mm at a time.

However, since the CB uses different frequencies, then the SWR will also change due to different frequencies, so it is normal to set the SWR on a mid channel frequency.

Hope this helps for a start.

beat regards,
Rustic

 

[kwondo]

SWR is used as an efficiency measure for transmission lines, electrical cables that conduct radio frequency signals, used for purposes such as connecting radio transmitters and receivers with their antennas, and distributing cable television signals. A problem with transmission lines is that impedance mismatches in the cable tend to reflect the radio waves back toward the source end of the cable, preventing all the power from reaching the destination end. SWR measures the relative size of these reflections. An ideal transmission line would have an SWR of 1:1, with all the power reaching the destination and no reflected power. An infinite SWR represents complete reflection, with all the power reflected back down the cable. The SWR of a transmission line can be measured with an instrument called an SWR meter, and checking the SWR is a standard part of installing and maintaining transmission lines.

 

[kwondo]

In short, witha swr meter if i remeber right if on the middle channel if the swr is high shorten the aireal if the swr is low, lengthen the airearl, some anteneas have a ring or grub screw adjustment, the length of cable can also effect the ratio,

im sure that a current cb'er will be along soon, my knowledge is 20 years ago

 

[spautoparts]

nice one. just had a look at a very well know aution site and you can pick them up for a tenner.
cheers for the advice everyone.:thumbs

 

[jims-terrano]

Right I use a pair of those "Truck Mirror Mountings" for my aerials with no problems at all, I replaced bolts with Stainless steel and they've been on my rails for years with no problem.
The connection to the metal body has nothing to do with reception but everything to do with the transmission side of the radio.
The chances are the aerial will be adjusted correctly anyway but may need adjusting, this makes it slightly longer or shorter using the little grub screw where the aerial rod goes into the spring.
Standing Wave Ratio is the energy that is not transmitted via the aerial and reflected back down to the radio. The energy reflected back down to the radio needs to be as little as possible.
Imagine the energy needs the right size hole to escape into the air, the hole being the aerial. So if the aerial is not the right size the energy can't escape and goes back to the radio and possibly causing damage.
So to measure this energy you use an SWR meter, you need to adjust the aerial to give as low a reading as possible on the meter. The aerial cable plugs into the SWR Meter and a cable from the meter to the radio. I'm sure there will be members close by you with the correct SWR Meter who'll help you check it.

I'm trying not to be too technical here but give you an understanding into what is meant. Feel free to ask further or PM me if you like.

 

[spautoparts]

Right I use a pair of those "Truck Mirror Mountings" for my aerials with no problems at all, I replaced bolts with Stainless steel and they've been on my rails for years with no problem.
The connection to the metal body has nothing to do with reception but everything to do with the transmission side of the radio.
The chances are the aerial will be adjusted correctly anyway but may need adjusting, this makes it slightly longer or shorter using the little grub screw where the aerial rod goes into the spring.
Standing Wave Ratio is the energy that is not transmitted via the aerial and reflected back down to the radio. The energy reflected back down to the radio needs to be as little as possible.
Imagine the energy needs the right size hole to escape into the air, the hole being the aerial. So if the aerial is not the right size the energy can't escape and goes back to the radio and possibly causing damage.
So to measure this energy you use an SWR meter, you need to adjust the aerial to give as low a reading as possible on the meter. The aerial cable plugs into the SWR Meter and a cable from the meter to the radio. I'm sure there will be members close by you with the correct SWR Meter who'll help you check it.

I'm trying not to be too technical here but give you an understanding into what is meant. Feel free to ask further or PM me if you like.

That makes alot more sense to me. LEGEND.
im gonna do some more research on the net. dont want to balls it up just yet:bow

 

[Fez_uk]

all newer type of CB radios will reduce their power if SWR is poor to protect the radio from damage.

I wouldn't worry about it too much, Bolt it to the roof rack/rail and see how it goes. Then after find someone local whos got a bit more experience to check the swr. Although it's not that hard.

 

[Lazy-Ferret]

Have a look at these posts for a good starting place..

http://www.nissan4x4ownersclub.com/forum/showthread.php?t=8571

http://www.nissan4x4ownersclub.com/forum/showthread.php?t=8572

http://www.nissan4x4ownersclub.com/forum/showthread.php?t=8573

http://www.nissan4x4ownersclub.com/forum/showthread.php?t=8574

http://www.nissan4x4ownersclub.com/forum/showthread.php?t=8617

 

[briggie]

Right I use a pair of those "Truck Mirror Mountings" for my aerials with no problems at all, I replaced bolts with Stainless steel and they've been on my rails for years with no problem.
The connection to the metal body has nothing to do with reception but everything to do with the transmission side of the radio.
The chances are the aerial will be adjusted correctly anyway but may need adjusting, this makes it slightly longer or shorter using the little grub screw where the aerial rod goes into the spring.
Standing Wave Ratio is the energy that is not transmitted via the aerial and reflected back down to the radio. The energy reflected back down to the radio needs to be as little as possible.
Imagine the energy needs the right size hole to escape into the air, the hole being the aerial. So if the aerial is not the right size the energy can't escape and goes back to the radio and possibly causing damage.
So to measure this energy you use an SWR meter, you need to adjust the aerial to give as low a reading as possible on the meter. The aerial cable plugs into the SWR Meter and a cable from the meter to the radio. I'm sure there will be members close by you with the correct SWR Meter who'll help you check it.

I'm trying not to be too technical here but give you an understanding into what is meant. Feel free to ask further or PM me if you like.

thanks jim :thumb2

 

[Thomas-the-Terrano2]

a useful site for advice and bits is 4x4cb.com

we have had bulk deals with them in the past.

 

[bry]

all newer type of CB radios will reduce their power if SWR is poor to protect the radio from damage.

I wouldn't worry about it too much, Bolt it to the roof rack/rail and see how it goes. Then after find someone local whos got a bit more experience to check the swr. Although it's not that hard.

Dont just bolt it on and see how it goes.You could damage your CB.

 

[bry]

Your SWR Reading should be around 1.5 or lower.But up to 2.0 is OK.Check your SWR meter on channel 1-20-40.And try to get a reading of 1.5 to 2.0 on these channels.