Sould I even bother...CB Antenna

[Airmapper]

So I need a CB setup, bad. I need to have it for an upcoming trip with other rigs, and I just lost my decent location with a 4ft Firestik on top the truck due to the RTT.

I have a horrible selection of options, so I came up with what you see in the image (there should be an image) below. It's a base loaded whip, fender mounted to a NMO base. I fabbed the mount from stainless sheet metal. I have an identical setup on the opposing side for my 2M/70cm rig, which works wonderfully, but that antenna is much shorter.

It's way too close to my FM (music) radio antenna, so I'll likely need to remove that when it's in use. I have a NMO cap so I'll probably only use the CB antenna when in convoy with other trucks, but still I think it's going to be a nuisance bouncing around, but it shouldn't snag on trees.

It needs to be tuned, so before I start chopping on it, is this setup even viable? I only need it for convoy use.

Thanks in advance.

 

[Robert Bills]

Go for it. If it doesn't work well enough you can always remove the hood mount and try a K400 or similar mount on the rear hatch. Instead of ditching the am/fm antenna try one of those Craven stubby antennas instead. If you get interference on your car radio when transmitting on CB you can remove it.

 

[Airmapper]

Go for it. If it doesn't work well enough you can always remove the hood mount and try a K400 or similar mount on the rear hatch. Instead of ditching the am/fm antenna try one of those Craven stubby antennas instead. If you get interference on your car radio when transmitting on CB you can remove it.

Thanks Robert, but I'm not worried about FM reception interference, but SWR kickback off that antenna being so close when I transmit on the CB. Turns out with good reason.

I just got back in from working on it. SWR was pegging the needle every time, I took off the FM antenna and it was still nearly pegged but I was getting a reading. I confirmed 40 was higher than 1, so started trimming. Finally got it to where 1 doesn't even move the needle, 19 is at 1.2 or so, and 40 is somewhere around 1.5 if I recall. If I put the FM antenna on, it jumps up to 2 or 3, and you can see the needle sway in unison with the antenna out there slightly shaking, darn this is sensitive.

So I definitely need to take off the FM antenna when I'm in a convoy and need to transmit, but I generally have the radio off, or pipe my music through the AUX port anyway when I'm with a group.

I left the antenna a tad long on purpose. If I get really motivated I'll fine trim it and see if I can squeeze a bit lower SWR out, but I probably won't since it's fair for as poor a location as it is in.

 

[4x4junkie]

I see at least a couple decent options there...


Best might be putting the antenna on the part of your roof rack that is forward of your RTT...
Does that part of the rack have a metal structure (crossbar, etc.) underneath it? If so, fab up some kind of bracket can be bolted through the plastic to the metal underneath (make sure said metal structure is also grounded well to the roof itself... It simply being bolted to the roof is usually sufficient, just make sure the bolts are tight and not corroded at all). If your RTT opens forward over top of that spot, put the antenna on a fold-over mount. Unless you're planning to actually talk on the radio while your RTT is deployed, this should work well.

Another option might be to simply move the antenna forward about 12" - 18"... This might get it far enough away from the car radio antenna to work OK (use of a center or top-loaded CB antenna such as a Francis or Firestik should also help... Base-loads tend to want nearly the entire whip length clear of the vehicle, which with the car roof, the car radio antenna, and your RTT there, it is not).

Whatever you do, don't start chopping on your antenna if the SWR is over 2:1, as this normally indicates a different issue such as the antenna's mounting location is not viable (poor ground and/or not enough clearance with the vehicle).

N/M, I see you already started... it's definitely too close to your car FM antenna for sure.

 

[PhulesAU]

Pftttt, just get a little more separation. like 6".

 

[Airmapper]

Best might be putting the antenna on the part of your roof rack that is forward of your RTT...
Does that part of the rack have a metal structure (crossbar, etc.) underneath it? If so, fab up some kind of bracket can be bolted through the plastic to the metal underneath (make sure said metal structure is also grounded well to the roof itself... It simply being bolted to the roof is usually sufficient, just make sure the bolts are tight and not corroded at all). If your RTT opens forward over top of that spot, put the antenna on a fold-over mount. Unless you're planning to actually talk on the radio while your RTT is deployed, this should work well.

No metal structure, it's all plastic between the main rack bars, and more importantly, that area is a storage bin and is in use. To use that area for antenna mounting I would need to completely remove the whole air dam assembly and loose my storage bin. If you've ever seen a Xterra void of it's air dam, it's kind of the same look as a shaved cat.... The roof rack itself is not electrically grounded to the roof, so I would have to drill directly into the roof. I did think of that area or use a mag mount, but I'm not willing to completely redesign that part of the roof to accommodate one antenna.

Another option might be to simply move the antenna forward about 12" - 18"... This might get it far enough away from the car radio antenna to work OK (use of a center or top-loaded CB antenna such as a Francis or Firestik should also help... Base-loads tend to want nearly the entire whip length clear of the vehicle, which with the car roof, the car radio antenna, and your RTT there, it is not).

The bracket I used is bolted to the fender using an existing fender bolt. Moving it down would require drilling a new hole. My aftermarket hood struts use the other bolt holes further down, and it's also sheet metal under there with no other free fender bolts until you get to the end of the hood. I have hidden kayak tie downs under those, but the tip corner of the hood doesn't seem like a good location. Besides I don't trust sheet metal to hold a robust heavy antenna like a Firestik flopping about over time.

Whatever you do, don't start chopping on your antenna if the SWR is over 2:1, as this normally indicates a different issue such as the antenna's mounting location is not viable (poor ground and/or not enough clearance with the vehicle).

N/M, I see you already started... it's definitely too close to your car FM antenna for sure.

Oh well, thanks for the warning but too late now. I did get the SWR down to safe levels so we will see how it does. I'll just remove the FM antenna when I use the CB, which is usually infrequent.

 

[Airmapper]

Pftttt, just get a little more separation. like 6".

Pfttt, it's easy when you don't have to design that solution, consider other objects that might be in the way like my hood struts, and build the mount yourself.

If there was a simple solution further down, don't you think I would have used it, seeing as how I thought it was a problem to begin with?

 

[4x4junkie]

Any options available at the rear of the truck? (ball mount on the rear quarter-panel, bracket off the rear hatch hinge or striker bolt, etc.)?

 

[East Coast Overland]

You could use a hand-held CB with a wired magnetic mount stubby antenna. It's what I use and I love this setup. The batteries on these radios last ridiculously long. I've had the same ones in my current radio for a year and still shows full bars on the battery indicator.

 

[PhulesAU]

Pfttt, it's easy when you don't have to design that solution, consider other objects that might be in the way like my hood struts, and build the mount yourself.

If there was a simple solution further down, don't you think I would have used it, seeing as how I thought it was a problem to begin with?

Well realistically you're over thinking this. it is a cb. unless you are getting verifiable resonance from your stereo antenna, there's no good reason to do anything. I like that position, it really close to what I'm running. it might also give the benefit of low clearance warning.

 

[4x4junkie]

Well realistically you're over thinking this. it is a cb. unless you are getting verifiable resonance from your stereo antenna, there's no good reason to do anything. I like that position, it really close to what I'm running. it might also give the benefit of low clearance warning.

The SWR jumping up into the 2-3 range when he puts the stereo antenna in place clearly suggests it is affecting the CB antenna's operation.

I still think with a little ingenuity an antenna can be made to work well on the roof rack right in front of the RTT without losing the storage space or negatively affecting the vehicle's aesthetics. Maybe put a small-medium size metal plate on (or underneath) the plastic air-dam part to support an antenna mount, then run a system of ground straps from the metal plate to the roof rack rails and to the roof itself for your ground.

 

[Airmapper]

The SWR jumping up into the 2-3 range when he puts the stereo antenna in place clearly suggests it is affecting the CB antenna's operation.

I still think with a little ingenuity an antenna can be made to work well on the roof rack right in front of the RTT without losing the storage space or negatively affecting the vehicle's aesthetics. Maybe put a small-medium size metal plate on (or underneath) the plastic air-dam part to support an antenna mount, then run a system of ground straps from the metal plate to the roof rack rails and to the roof itself for your ground.

I like it, that might work. Still sketchy from a ground plane standpoint, but the extra height and fewer obstacles in proximity would be favorable on all other counts.

As for the options on the rear, maybe and maybe not. I've seen some Xterra owners make a bracket off the tail-light area, but most claim the heavy Firestick bobbing around eventually rips it out of the sheet metal. A clamp on the door itself doesn't sound appealing as it would interfere with opening the door possibly.

 

[AaronK]

Just get an ARB bumper, it has antenna mounts 😀
Enabler!
Enabler!

Sent from my OnePlus One using Tapatalk.

 

[4x4junkie]

I like it, that might work. Still sketchy from a ground plane standpoint, but the extra height and fewer obstacles in proximity would be favorable on all other counts.

As for the options on the rear, maybe and maybe not. I've seen some Xterra owners make a bracket off the tail-light area, but most claim the heavy Firestick bobbing around eventually rips it out of the sheet metal. A clamp on the door itself doesn't sound appealing as it would interfere with opening the door possibly.

Not sketchy at all if your SWR is good.
Run four straps (two each side) from the plate to either the roof itself or to your roof rack's side rails, assuming they are metal (try to make somewhat of an "X" configuration with the straps if you can), then put a strap (short as possible) at both the front & rear of each side rail to where it's bolted down. I think it would work well.

And FWIW, a Francis is about half the weight & rigidity of a Firestik (and IMO is a better antenna to boot). The Francis CB-26 Hot-Rod would be the one to get (and is what I use on the roof of mine).

 

[owyheerat]

You could use a hand-held CB with a wired magnetic mount stubby antenna. It's what I use and I love this setup. The batteries on these radios last ridiculously long. I've had the same ones in my current radio for a year and still shows full bars on the battery indicator.

Sorry to hijack thread. @ CDN_S4 could you PM me links or description of handheld and mag antenna you use.

Thanks