CB aerial Q's

[Sweety]

Will have my CB in the truck at long last in the next day or 2 once i've finished my fascia:thumb2 I was thinking of poss mounting the aerial on the front of the truck with a bracket coming off the ones i've made for a set of spotlights but was wondering how people have found the SWR & reception having their aerial's on their A bar or winch bumper ?
For the time being i've dug out my old mag mount & wondered how people have routed the coax into the cab & where ? had it coming in via the top of the door on my old SWB but when it rained heavy water dripped off the coax on the inside:doh

 

[Barrbeast]

Reception from mine is good and I've got mine mounted on the winch bumper mount Aussie style

Makes a good height reminder as well...

 

[jims-terrano]

I'm not convinced by safety issues for aerials on the front, if it would pass an mot with it fitted on the front then fine thats ok just my opinion. I fitted a pair of mounting brackets on the ends of the roof rails and fed the coax down the tailgate aperture and created a drip loop tucked down between body and rear bumper. Then fed the coax in along the bottom edge of the tailgate, not had a problem with water leaks and they have been fitted for 13 years so far.

 

[Lazy-Ferret]

I have both my aerials on the front A bar, and had no problems getting the SWR down. As far as range goes, since I only use the CB for close range stuff, I can't comment, but the HF radio seems to match the range of all the other SE4x4R guys.

Mine has passed 2 MOT's with the CB aerial on the front, and the last one with both.

 

[The Patrolman]

Ooh ooh, this is me too:thumb2
Got my aerial to fit before the dales trip. Front back high or low:nenau
What is swr , how do you measure it and how do you adjust it too:nenau

 

[Barrbeast]

Mine passed MOT with the winch bumper mounted aerial as well, no issues and very secure (bumper came from factory with mounts welded to it).

Patrolman, I'd go front, could mount it off your new bumper - should provide a good ground plane. :thumbs

I like it at the front as it means things rarely get caught in the coil :nenau

 

[AlexD333]

Best reception is central roof, don't ask my why, but it used the cars body as a receptor or some such.

 

[Paff]

Ooh ooh, this is me too:thumb2
Got my aerial to fit before the dales trip. Front back high or low:nenau
What is swr , how do you measure it and how do you adjust it too:nenau

http://www.thunderpole.co.uk/cb-radio-guide-swr.html

 

[Lazy-Ferret]

Best reception is central roof, don't ask my why, but it used the cars body as a receptor or some such.

It's not got anything to do with reception, Alex, a bit of wet string will pick up radio waves, it's all about the transmission.

In very basic terms, the metal car body pulls the signal from going straight out the end of the antenna, and drags it back down to travel horizontally along the body. The more metal around the aerial, the better it's pulled down, and if the metal is evenly spaced round the aerial, it pulls it down evenly in all directions.

Basically cars with the CB aerial on the front will transmit further behind than in front.

 

[solarman216]

It's not got anything to do with reception, Alex, a bit of wet string will pick up radio waves, it's all about the transmission.

In very basic terms, the metal car body pulls the signal from going straight out the end of the antenna, and drags it back down to travel horizontally along the body. The more metal around the aerial, the better it's pulled down, and if the metal is evenly spaced round the aerial, it pulls it down evenly in all directions.

Basically cars with the CB aerial on the front will transmit further behind than in front.

As said, Rick

 

[Sweety]

Thanks guy's:thumb2 I do like the look of the aerial on the front not sure how the Mrs will feel about it as it'll be on her side:lol
Sadly don't have roof rails on mine Jim other wise I would have mounted it there, hoping to get my old clamp on roof rails back & will mount it onto the light bars attached to them if I go with the mag mount. Got a 5ft & 3ft springer aerial but if I go for a front mount thinking of getting one of these http://www.thunderpole.co.uk/large-cb-antennas/thunderpole-voyager.html unless I can get a new whip part for my old bull whip as that pulled in & pushed out signals fantastic upto 30 miles away

 

[solarman216]

Ooh ooh, this is me too:thumb2
Got my aerial to fit before the dales trip. Front back high or low:nenau
What is swr , how do you measure it and see how do you adjust it too:nenau

SWR is standing wave ratio, this is a measure of how much your set is actually getting out to the world, if your antenna is not in tune with the frequency you are on then some will be coming back to the set, too much and your output transistors will fry, you need a SWR meter in the coax to your antenna to see what it is, then adjust the length of the antenna to get the reading as low as possible, Rick

 

[solarman216]

my old bull whip as that pulled in & pushed out signals fantastic upto 30 miles away

How you manage that, you got a burner? I have had CB from the 70's AM/FM with/without burners, and mobile never got more than a couple of miles, after all that is what the frequency is designed for, if we could all transmit 30 miles then every channel would be awash with interference from afar, cell phone are the same, if they had a greater range then the whole country would be awash with interference, hence the cell idea a small range around a local mast, granted there are those that transmit vast miles on 27 but they have very specialised antenna that are highly directional on great big masts, Rick

 

[Banshee]

Centre of the roof, mag mounted every time for best output in all directions. I'm pushing 50 watts out of a KL203 as well :naughty

 

[solarman216]

Centre of the roof, mag mounted every time for best output in all directions. I'm pushing 50 watts out of a KL203 as well :naughty

So in all honesty how far does that get you, 2 miles maybe a little more, honest now cos if you say more I will need proof, Rick

 

[Banshee]

So if I sit on Turners Hill in Tividale near me, 880ft above sea level I have had radio reports that I'm getting out to and receiving at least 6 miles

 

[solarman216]

OK on a high spot you gain but more realistic level ground as in motorway contact other driver going the other way how long do you get to talk 1 min. maybe 2 if you are lucky, CB is ok for say a convoy but even then can be hard I remember coming down the mountain passes in France I was tailgating my mate in front and he could not get me ten miles on and no problem but if he got 2 miles ahead no score, and at the time I was running a DV27f base coil loaded antenna with a 100w burner , Rick

 

[AlexD333]

I'm too baffled about cb radios, we went to west Wycombe hill a few weeks back I was pushing 10 miles with out mag mount only... I think it's 6 or 8 watts? :nenau

The aerial had been set up to 1.1 :nenau

Should I get a burner then?

 

[jims-terrano]

CB is really best for convoy type use like Rick suggested. That said CB is in the HF spectrum and as such can potentially can travel long distances even world wide especially if using Sideband but the chances of all the correct circumstances coming together are quite slim. Weather and other natural conditions also play their part too.
A burner will only amplify your transmitted signal, even then often not very efficiently or effectively. Also another way of looking at it is that as a standard setup your range and others is say 5 miles. You fit a burner and say extend your transmitted range to say 10 miles. 10 miles away someone tries to reply to you but can only get 5 miles, you are not going to receive them. You can buy a preamp which should amplify signals that you receive.
As stated previously the transmitted power pattern can vary depending upon where abouts on the car it is placed and generally speaking an aerial placed in the centre of the vehicle mass and as high as possible will give the best results but not always practical.
SWR is easily described by a ball and a pipe, the ball is your transmitted signal and the pipe your aerial. The ball will travel through the pipe when matched just right to the bore of the pipe. The size is demonstrating the frequency of your signal, the antenna has to be tuned to the matching frequency. If they are not matched a percentage of power is not transmitted by the aerial, this power is reflected back down the aerial cable (coax) and can damage the transmitting radio. So it is best to tune the antenna (adjust longer or shorter) so that you get the least amount of power reflected back down to the radio. This is SWR or swar as people refer to it, this is measured by a meter placed between the aerial and radio.

Sorry trying not to get too technical.

Interesting that an aerial protruding on the front of a vehicle isn't an mot fail, good news though as it seems a very practical spot to mount aerials.

Give the aerial a good connection to the whole of the vehicle body and you should be able to achieve a good SWR.

 

[Banshee]

6 Watts out of the Rig and the KL203 on the back with a 2ft Sirio Mag Mounted Antenna I know I can get further than that up Turners Hill but I've never spoken to anyone further than that but yeah Rick is right in normal circumstances you're only good for a couple of miles