Cb radio install

[Moorlands]

Trying to get fixed up for silage so can be in contact with everyone else. Installing a new Thunderpole t1000 and orbitor full size aerial with body mount bought as a new kit from Thunderpolemade a bracket to come up from drawbar storage point on jd6830 and put set meter on and its reading just a fraction under 3 on channel 1 and over 3 on channel 40 what do I do to improve it? Thanks in advance.

 

[Kiwi Pete]

When you say "coming up to 3", what is?
Have you got an inline watt meter on it?

 

[Moorlands]

Auto correct had changed swr to set! swr meter So only just out of the red on channel 1 and in it on channel 40.

 

[Kiwi Pete]

Without googling your particular antenna, I'd say it would probably have an swr ratio of about 1.5: 1 or so..
If that were the case you should have 3 watts going up the spout and 2 watts coming back!
Unfortunately it will either be as good as you can get it, unless you can tune the length of the whip to a better forward reading.
Sometimes the length of the coax can play a factor too.
But if I'm understanding you correctly, it may be as good as gold how it is? Most commercial jobs have a reasonably high SWR just because they don't go to much hassle to match them and tune them.

 

[Kiwi Pete]

Just been thinking a bit longer.
If SWR is 3:1, and better at the low end of the band, then the whip is already on the short side. And pre-tuned according to the guff so no adjustment
If it was better at the top end of the band I'd say lop 5mm off and try again, but that's raising it's resonant freq, so the opposite of what you're wanting.
Short of monkeying around with the length of coax, probably not much you can do sorry.

 

[Hesston4860s]

Sounds to me like your aerial is far to low if you've got it mounted nr the drawbar bracket, you ideally need it in centre of the roof or at worst on a mirror arm !.

 

[clbarclay]

Quite a few cb tuning guides online. Think I used this one last time.

http://www.4x4cb.com/public/page.cfm?Page=795


Adjusting antenna length is good for fine tuning the optimum across thechannel range, but if the best you have is nearly 3 then there is somethingelse not right that needs sorting first. Ariel position and ground plane might be the place to start making changes.

 

[Kiwi Pete]

Yep and that is the other thing^^^^ if it is close to another metal object, such as a cab pillar or exhaust, that will detune it.
Best away from them on your bonnet or roof (or out the side for the trees to wipe off)
I have my uhf one pointing down from the roof on my sidebyside to keep it away from harm

 

[DrDunc]

Aerial is too low.

Full length whips don't last long on a tractors roof though. Most here run 90cm "mini" ones.

To reduce the standing wave ratio it needs to be away from big chunks of metal that'll reflect the signal (as folks have already said!).

 

[Moorlands]

Is this no good like this then? Don't want it on cab cos need to be able to go in buildings

 

[Stuart2]

At the moment its 2 short, however it's probably to close to the cab etc as others have said. Ideally move to a better position bonnet?? Or just try lengthening the whip , possibly by adding a bit of wire securely. You do need to be under 2 if you want your output trannys to last out the silaging. Failing all that a little tuner/ matcher/atu.

 

[DrDunc]

Is this no good like this then? Don't want it on cab cos need to be able to go in buildings

Mounting it there is a reason why you're getting a higher swr than ideally you'd want.

This article explains it, click here.

If you're worried about buildings, you can put it on a quick release or swivel mount.

However whip aerials will go into buildings with little more than a foot of clearance. The (90cm) aerials on my tractors will be in and out of sheds several tines a day, every day throughout the winter.

The aerial in this picture is three years old and is absolutely fine with scraping into buildings.

 

[Moorlands]

Mounting it there is a reason why you're getting a higher swr than ideally you'd want.

This article explains it, click here.

If you're worried about buildings, you can put it on a quick release or swivel mount.

However whip aerials will go into buildings with little more than a foot of clearance. The (90cm) aerials on my tractors will be in and out of sheds several tines a day, every day throughout the winter.

The aerial in this picture is three years old and is absolutely fine with scraping into buildings.

View attachment 522972

At the moment its 2 short, however it's probably to close to the cab etc as others have said. Ideally move to a better position bonnet?? Or just try lengthening the whip , possibly by adding a bit of wire securely. You do need to be under 2 if you want your output trannys to last out the silaging. Failing all that a little tuner/ matcher/atu.

Sounds to me like your aerial is far to low if you've got it mounted nr the drawbar bracket, you ideally need it in centre of the roof or at worst on a mirror arm !.

Yep and that is the other thing^^^^ if it is close to another metal object, such as a cab pillar or exhaust, that will detune it.
Best away from them on your bonnet or roof (or out the side for the trees to wipe off)
I have my uhf one pointing down from the roof on my sidebyside to keep it away from harm

So how much higher should I mount it seen plenty people mount them in this position would another 6 inch on my bracket do it to get it above the bonnet?

 

[mushnt grummmble]

Also,where are you swr-ing your set??
In the yard or field

 

[Stuart2]

The ideal spot is on top of a metal bonnet/roof just not close to the side. Mushntgrumble also has a point.

 

[Bobthebuilder]

get it in the middle of an angle iron bracket across the 2 cab lifting bolts, you'll need to get a couple of longer bolts and put some washer spacers in to lift it just clear of the cab, no problem on the 7530 I had mine on, on a case puma atm

 

[timmyboy]

Why not just try it some where else just to see if all is ok......no short on the co-ax plugs or a bad earth somewhere. It's a long while since I was into CB's but I seem to remember substituting the whip for a brazing rod or something of the same thickness before hacking the whip about. Are you sure too that the swr meter is correct and has no faults with the patch lead? An swr of three....and nearly in the red as you say.... irc is next to a dead short.

 

[mushnt grummmble]

Why not just try it some where else just to see if all is ok......no short on the co-ax plugs or a bad earth somewhere. It's a long while since I was into CB's but I seem to remember substituting the whip for a brazing rod or something of the same thickness before hacking the whip about. Are you sure too that the swr meter is correct and has no faults with the patch lead? An swr of three....and nearly in the red as you say.... irc is next to a dead short.

A shed will reflect enough to send it that high

 

[Kiwi Pete]

The higher and clearer the area the better.
We used to swr our ham radio whips out in the yard on a wooden sawhorse but....
I don't think many people care about SWR given where you see aerial mountings?
Ideally just mount it as far away from steelwork as you can get, the antenna should be pretty good as is

 

[Father ted]

Use to always mount ours on wing mirrors on the Deere,cut about 100mm off standard coil aerial,swr reading between 1.3 & 1.6.
With the burner switched on could talk on a good day up to 25 mile away.