Mounting a CB antenna on a modern hatchback without drilling?

[wolrah]

My roommate has expressed interest in having a CB in his car (and possibly picking up his ham ticket later) after seeing how useful it is in my car to avoid speed traps on the highway. Unfortunately, he drives a 2009 Volkswagen GTI. Now I'm no stranger to mounting antennas on vehicles you wouldn't expect to find them on, as I currently have CB, 2M, and 440 on the trunk lid of my 2002 BMW 325i, but since I have a sedan it's easy for me to just do trunk lip mounts and call it a day (yes I'm going to do it right and drill later this summer). His hatchback doesn't really have any appropriate areas for a normal lip mount and he's paranoid about paint damage (it's a black metal flake paint which is apparently very hard to color match, often requiring a full respray) so he doesn't like mag mounts. Obviously drilling the roof is entirely out of the question.

Vehicle in question:

(not actually my roommate's car, but the same thing minus the sunroof and bright red paint)

The options we've come up with so far are as follows:

1. Lip mount to the rear of the hood near the windshield. Downside is this area is sloped forward and given that my trunk lip mounts get loose after a year or so if the wind stress is the other direction these probably won't last long.

2. Install OEM or aftermarket roof rack to factory mounts, bolt on no-ground-plane antenna. Downsides are being tied to the antenna/mount/coax combo shipped in the package, plus NGP setups seem to have a bit of voodoo involved.

3. Install OEM or aftermarket roof rack to factory mounts, purchase large sheet of metal, bolt to roof rack, drill mount through center of metal sheet.

4. "Universal" lip mount like a Comet CP-5 mounted high on the hatch. I'm unfamiliar with how sturdy these are with multiple points of adjustment, but if it works well it might be the simplest option. Also has the benefit that if/when he gets his ham ticket a second could be placed on the other side for a 2M/440 combo.

5. Mag mount with padding underneath to protect the paint. I have no idea if this would screw with the ground, nor do I know how large of a magnet setup this would need. All I know is that the cheap 4.5" magnet base I bought when I originally got my CB couldn't even hold its 40" or so antenna up at 75 MPH, much less a larger whip at higher speeds.

I like options 3, 4, and 5 personally. The hood mount would be pretty fugly and seems to have plenty of potential problems and the no ground plane option just doesn't seem right. Option 3 in theory should be ideal for radio performance as long as the roof rack is large enough to fit a properly sized sheet of metal in there, though I might be missing something. Option 5 comes in a close second, but large magnets would be required to handle a CB whip at the speeds this car is capable of.

I'm wide open to other suggestions as well, just keep in mind the goal is to allow the vehicle to be returned to as stock as possible from the exterior. If we need to drill in a hidden area, that might be an option depending on where.

 

[robertmac]

Keep to the speed limit and you won't have to worry about needing a CB [which is next to useless anyhow]. But if you do use a magnet mount, you won't have to worry about it falling off if driving within the speed limit. The place for speed is at a drag strip or race track.

 

[BonziBuddy]

Any CB antenna on a GTI is going to attract a lot of unwanted attention

 

[wolrah]

Keep to the speed limit and you won't have to worry about needing a CB [which is next to useless anyhow]. But if you do use a magnet mount, you won't have to worry about it falling off if driving within the speed limit. The place for speed is at a drag strip or race track.

1. CBs are in fact very useful on the interstates.
2. I already said even the largest mag-mount I've used fell off repeatedly at 75 MPH, which is the limit on many highways. Driving in to the wind it fell off as low as 60.
3. If the speed limits were set for safety rather than revenue I might give a crap, but when someone puts a 60 MPH limit on 6+ lanes of smooth interstate you can't argue they're not full of ***** so I choose to ignore the limit where appropriate and utilize countermeasures to avoid and/or defeat speed traps. It's not like I'm doing 90 through school zones here, I'm typically only exceeding the normal flow of traffic by 5-10 MPH.

Any CB antenna on a GTI is going to attract a lot of unwanted attention

The point isn't to avoid attention, but to make sure that when someone does pay attention that they have nothing to work with. Also, you'd be surprised. The worst that's come from two years of having a big CB whip on the back of my BMW is a few cops giving me evil looks when I roll past them with the mic in my hand reporting the bear at the XX stick.

 

[W0JJK]

Comet makes Mounts like this

Part number CP-5 3-8x24 http://www.cometantenna.com/pdfs/CP-5_mount_series.pdf

You can choose an NMO or 3/8 thread antenna for the mount you want.

 

[wolrah]

Comet makes Mounts like this

Part number CP-5 3-8x24 http://www.cometantenna.com/pdfs/CP-5_mount_series.pdf

You can choose an NMO or 3/8 thread antenna for the mount you want.

Can you speak to how sturdy these are? This exact model is #4 in my list of options and seems like it'd be the simplest to deal with overall, but I'm concerned about it falling over or breaking at speed under the load of a standard CB whip.

 

[canav844]

CB is great for getting details on backups which has saved me countless hours of stop and go (in a manual trans vehicle that's years of my life back), and it's got scanner like chatter on a good Friday afternoon/night as most State Trooper and County Sheriffs have them in their squads around here and have taken many a hit and run or DUI calls, and then I usually get to drive past them up ahead.:lol: I've got a HAM radio too, but long trips 20min then look up a new repeater dial it all in, get 20min more repeat gets old, and if you can find anyone on simplex (a feat in and of itself) you've got the for less than 5min of conversation; because most with the CB are on the highway, if it's a decent group of people (80% of the country it is, it's that 20% that carries the reputation) then half of those people are going the sae direction and you can chat while cruising the length of the Nevada desert.

Here's how I did it, it goes about 6months before I remove it to clean under it and reapply wax to protect the paint even more. But is rock solid, no loose issues.

Antenna is a Antenex CB27

Left to right it goes CB, HAM (removed factory AM whip replaced with NMO mount and Comet SSB-2), Scanner (Radio Shack through glass)

The mount is the Comet RS-720NMO

And the Cobra 29LTD Chrome CB behind the passenger seat (as it lives on 19 and doesn't require messing with) with external speaker

Never attracted any unwanted attention, and never got any attention at all unless it was night-time and the trucks saw the blue glow and wanted to tell e how much better their illegal setups were, I played dumb like the volume was down and moved on.

 

[W0JJK]

No, I use through hole mount NMO on my cars.

I have seen them on many hams cars.

Are you going to put like a 3 or 4" antenna on the mount?

SW

 

[kilowa22]

4. "Universal" lip mount like a Comet CP-5 mounted high on the hatch. I'm unfamiliar with how sturdy these are with multiple points of adjustment, but if it works well it might be the simplest option. Also has the benefit that if/when he gets his ham ticket a second could be placed on the other side for a 2M/440 combo.

The Comet lip mount for the hatch back is what I used on a dodge colt. If you mount it correctly it doesn't get in the way, that includes tying down the coax cable in the car, too. Don't use mag mounts, someone can just walk up and snip the coax then walk off with it. Also mag mounts are not very sturdy, if you get a grain of sand or water underneath the thing will blow off leaving you dings and scratches.

Having the antenna permanently mounted so it is out of the way is the best. You can also buy quick disconnect models so you can quickly take off the antenna, leaving the mount and put the antenna in the hatch back when at the mall.

 

[fischlerpromo]

The place for speed is at a drag strip or race track.

I live in Los Angeles, well the San Fernando Valley to be exact. a nice area.. but a setup like that would not last long in the car...

Never used to be this way here, I drove around for years in the 70's with a CB in play view and a Firestick antenna on the trunk,(I think that was the name of it.. ?), oh and 100 Watt kicker just to be able to be heard among these bass units w/ 1K Watts of power.

 

[GregFromOregon]

5. Mag mount with padding underneath to protect the paint. I have no idea if this would screw with the ground, nor do I know how large of a magnet setup this would need. All I know is that the cheap 4.5" magnet base I bought when I originally got my CB couldn't even hold its 40" or so antenna up at 75 MPH, much less a larger whip at higher speeds.

Won't work.
I tried to use the thin clear film that you can hardly see that is for rock chip protection and the SWR's were WAAAAAAAYYY off. I have a Wilson 1000 mag mount with 5' whip in the center of my roof and run 80-85 mph without it ever coming off (Focus ZX3). I've seen Ham's using a bracket that comes out from under the rear bumper, don't know if it would work. I like that Comet bracket that was mentioned above, gonna look into that myself!

 

[Kodiackjack]

Antenex C27

I just bought the Antenex C27 Pictured above (described as a "CB" 27) Now, I was wondering, what connector would I need? I bought the Exact same mount, (RS-720NMO) and am putting it on the exact same type of car (VW Golf) Thanks. BTW, If you were all wondering what CB I'm using, its a Cobra 29 WX, and right now, I have a p.o.s. radio shack antenna on it. (which doesn't work too well if you ask me.)

 

[RodStrong]

I would drill and put a Larsen or Maxrad NMO whip cb antenna on the roof. Something along these lines: Larsen NMO27C Low Band 27-30 MHz CB Antenna Although it certainly wouldn't be easy to miss, it wouldn't be as loud or as gawdy as a fiberglass antenna or several other types.

I have a whip antenna on my work truck and several others we use, and I'll never go back to a fiberglass set up again.

If you want a CB in that rig, do the antenna right. It's the most important part of the equation.

Good luck.

 

[LtDoc]

If drilling a hole is out of the question then you are limited to something like a 'lip-mount' or a mag-mounted antenna. Both have 'size of antenna' limitations. Mag-mounted antennas do work. Of course, the size/strength of the magnet does play an important part in how they will stay on the vehicle. Bigger is better to some absolutely ridiculous extent. 'Lip-mounts' work if the attached antenna isn't too large. Because of how they attach there are limits, checking and re-tightening the setscrews is a good idea. Usually, any scarring of paint is on the 'back-side' so isn't all that noticeable. It's also a fairly good idea to make sure the 'lip' the mount is attached to is making good electrical contact with the rest of the vehicle. Hinges aren't always metal to metal type thingys, you know?

Mag-mounts work by capacitively coupling the 'ground' side of the antenna to ground. The surface area of that magnet acts as one 'plate' of a capacitor, the metal body it sits on acts as the other 'plate' of the capacitor. The space between those two surfaces is the dielectric of the capacitor. Increasing the spacing of those two 'plates' by using padding of some sort decreases the amount of capacitance and therefore means having less coupling or worse connections to ground. Capacitive coupling is frequency dependent. The higher the frequency the better a particular size of capacitor will 'conduct'.
It doesn't much matter what it is, if you place something on top of paint, that paint will be abraded. Wax may help with lessening that abrasion, but it's still gonna happen. So will removing/replacing that magnet, so you're caught in a 'Catch-22'.
I've found that most manufacturers of 'lip-mounts' will put a size limit on their mounts, it works with antennas of X-length and less. I tend to take their recommendations as sort of optimistic, you know?
do what you can with what you have to work with, then live with it.
Have fun.
- 'Doc

 

[drewdownkali]

How on earth

Hey canav844, how on earth did you get that laird/comet setup to work?? I bought the laird cb27s and the comet cp-5nmo (730 mount), and the swr is 3 and above. Comet can't figure it out, guy at truck city in Tacoma Washington couldn't figure it out. HELP!!!! Bout to send it all back and get a mag mount which I was trying to avoid.

 

[drewdownkali]

the guy

All John at the antenna farm can tell me is the antenna needs a good ground plane. Acts like I'm a retard. Tried all kinds of options that Mick Stwertnik of NCG (comet) gave me and he is out of reason why it is not working.

 

[drewdownkali]

Lip mount

John told me to try Max rad MLBDC2700 and that the laird needs a good ground plane. I told him that this maxrad and the laird have nearly identical descriptions (less ground plane needed, base, etc). I mentioned that I had heard about the defrost elements possibly being a problem and he thinks that has to be it. I imagine Canav's vehicle probably has them too, but no issue I'm guessing. Weird.

 

[canav844]

Hope you haven't sent it back was a fluke that I caught this thread in the new posts, drop me a PM next time.

The mount has screws that meet the metal of the hatch, which is grounded to the rest of the car, so as long as those had a good connection that part was just fine, I did have to trim the antenna, the bag had some approximate lengths, then it was a matter of checking Ch1 and Ch40 to determine the length to get the SWRs down on Ch19; remember it's easier to go shorter than it is to make the antenna longer. If you're having trouble getting solid connections I wonder if a little dielectric grease may help. Remember the issue may not be in the antenna, but could be the result of a pinched feedline, make sure there's no kinks or tight spaces the coax has to run through that could be shorting things out before it ever reaches the antenna.

Never heard of Defrost elements being an issue, but if they're metallic and packed tightly together I could see them acting as a reflector.

Photos of your setup? What kind of car is on?

 

[drewdownkali]

I am new to these forums. Added you as a friend but no idea how to pm. Have went through all possible reason why it won't work with the owner og NGC(comet), he doesn't know what the problem is. I even mounted it on the hood last night and swr still above 3 on 1 and 40. So I know its not the defroster elements. Totally lost. Ordered a mag nmo mount. If it doesnt work then I would have to think it's the antenna.

 

[drewdownkali]

Guess I'm still too new for this thing, can't message you. I have not been able to contact Laird (antenna maker). Everything is grounded. I even ran a ground strap between the hatch and rest of car as the hatch door was not getting a very good ground. I got all this because I wanted a clean nice looking setup. My friend got some cheapo mount and antenna and mounted it on the mirror of his 88 s10. no problems. I buy trhe expensive nice stuff and it doesn't work. Lol. my luck.