CB antenna on ARB - ground? SWR?

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That don't sound right to me. Let me go do a little checking and I'll get back to ya on this one.
 
BMAN said:
That don't sound right to me. Let me go do a little checking and I'll get back to ya on this one.
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After checking it on the new one and finding continuity there as well I posted the question on a CB forum. Apparently it shows short at certain Ohm ranges on the multimeter but not others. I would assume the inside and outside of the S0-239 have to connect at some point inside the CB circuitry. Got me. I've hooked up several CB but can't seem to figure it out this time. About to yank it all and go buy new stuff.
 
Don't do that yet. Let's figure out your problem first.

I have also posted up on the forum that I've lurked on for some time now. We'll see what we can come up with.
 
ground plane

Just want to tell you guys --
That even thought A*B includes the mount on their bumpers it has to be one of the worst places to mount an antenna..
It will antenna will work but not at it's best.

I may be just anal BUT in the centre of a metal roof is by far the best..
You will get your best RF ground plane in this location.
You will not get your best ground plane on your front or back bumper..

If you do not want to drill a hole in your cruiser roof, stick a roof rack up there.
Mount your antenna in centre..Verify all is grounded - can not be said enough-verify all is grounded.. No rubber feet on the roof rack etc.

You should be striving for a 1.1 : 1 or less match when tuning your antenna.
Once your installation is done.. you can measure the RF signal coming off your truck with a field strength meter. This will tell you which way most of your signal is leaving your vehicle - front - back- sides..etc..

Good luck
 
IBCRUSN said:
get an antenna that doesn't need a ground. I installed a no ground type on my 80 with the antenna mount bracket and a quick disconnect. IIRC i was getting 1.2 on the SWR.
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ditto that ours works good and it is on the ARB
 
1990 LJ78 said:
Just want to tell you guys --
That even thought A*B includes the mount on their bumpers it has to be one of the worst places to mount an antenna..
It will antenna will work but not at it's best.

I may be just anal BUT in the centre of a metal roof is by far the best..
You will get your best RF ground plane in this location.
You will not get your best ground plane on your front or back bumper..

If you do not want to drill a hole in your cruiser roof, stick a roof rack up there.
Mount your antenna in centre..Verify all is grounded - can not be said enough-verify all is grounded.. No rubber feet on the roof rack etc.

You should be striving for a 1.1 : 1 or less match when tuning your antenna.
Once your installation is done.. you can measure the RF signal coming off your truck with a field strength meter. This will tell you which way most of your signal is leaving your vehicle - front - back- sides..etc..

Good luck
Click to expand...

Sounds like you likely know more about it than I do. After sorting out the mess my SWR is very low - 1.1 on channel 19. 1.3 on channel 1. I probably won't mess with tuning it any further. Would I still have better performance on the roof?
 
You will have better performance on the roof. Also remember that SWR simply measures the amount of match/mismatch in the impendance of the whole system. Simply a low SWR rating does not imply that your effective radiated power (ERP) is good, as it may be significantly diminshed. If you have competing impedance imbalances in the system, it can suck your power, but in aggregate still report a low SWR as they may cancel each other out.
 
If you want to check the radiated power pattern around your ride, use a field strength meter once you have finished with matching (tuning) your system.
 
I'm wondering where you guys wheel that a CB antenna on the roof won't get torn off 10' into the trail. Here in the PNW, overhanging trees are a constant companion. I'm trying to get a CB figured out for a trip this weekend and my head is reeling. I was all set to mount a 48" fiberglass antenna on the top of my ARB and buy a cheap Uniden 510 or the in-dash Cobra and head off into the woods.

Like many things on this board, there is just no concensus. With no roof rack to bolt it to, I am pretty much left with a mag mount on the roof, but I watched another guy have his ripped off several times on a run a couple months ago. Not interested. How short of an antenna could one get away with up there? I saw a little 6" fiberglass number at radio shack yesterday. How about duals on both ARB slots. Does that solve any problems, or just create more? Total FNG when it comes to CBs. Sorry.
 
Dual antennas need special feed lines. The shorter you go, the less the performance you'll see. If you don't mind not being able to get very far with the radio, go for a rubber ducky, or even a small whip on the ARB. I'm never saying it's wrong (in fact I have my Ham antenna there :O ), just not optimal.
 
C6H12O6 said:
Thanks. I'm not trying to reach my dead father in 1959, just keep up with the chit chat on the trail. I'll probably end up with a 3-4' fiberglass antenna on the ARB.
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LOL :beer:
 
Im mounting my wilson 1000 to my INTI rack. The guys at the shop recommended sanding off the paint where i mount it and make sure to take off the rubber boots on the gutter legs. Has anyone ran into rust forming really badly after taking the rubber boots off? thats my only concern to doing it.
 
Pskhaat said:
Dual antennas need special feed lines. The shorter you go, the less the performance you'll see. If you don't mind not being able to get very far with the radio, go for a rubber ducky, or even a small whip on the ARB. I'm never saying it's wrong (in fact I have my Ham antenna there :O ), just not optimal.
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Plus they need to be 8 feet apart to work correctly.
 
Also remember that SWR simply measures the amount of match/mismatch in the impendance of the whole system. Simply a low SWR rating does not imply that your effective radiated power (ERP) is good, as it may be significantly diminshed. If you have competing impedance imbalances in the system, it can suck your power, but in aggregate still report a low SWR as they may cancel each other out.
Click to expand...

This, folks, is the single most concise, and accurate explanation why so many radio installs work poorly.

I'm wondering where you guys wheel that a CB antenna on the roof won't get torn off 10' into the trail. I'll probably end up with a 3-4' fiberglass antenna on the ARB.
Click to expand...

Truth being told, we have low branches on our trails as well. One solution that has worked well is to place a mount high on the rear hatch using a taller antenna that can be unscrewed and replaced with a shorter one for the trail, then back to the original when back on the road.

Mounting an antenna on a bumper is one of the most inefficient locations because of poor grounding and ground (earth) effects that multiply standing waves on the line that may not be accurately reported by an SWR meter. Read the first quote again... this is a very important point.

Cheers, R -
 
Always ground your antenna. Run thick wire #10 or the stuff they use to ground computer rooms with from the base of the antenna where the coax shield connects to the antenna. Connect the thick wire to the vehicle frame. Grind the frame and make a good connection. Don't use half ass crimp on connectors unless they are soldered. If you have ignition whine or point noise try running say #12-16 ga wires, pos and neg direct to your battery. (With a fuse inline) The battery will act as a capacitor and help cancel some of the noise. Also run your wires away from the ignition system as much as possible.

Or get of the chicken/criminal bands and get a ham ticket.

PS To the guy running tubes, your not running an amp are you? Love to turn you in.
 
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