Why We Fitted Our UHF Antenna on Our Roof Rack with a Folding Antenna Mount
In this post we discuss why we moved our UHF antenna from our bull bar to the roof on our Rhino Rack Pioneer Platform using a folding antenna mount. The obvious benefit in having your UHF antenna mounted as high possible is going to be improved signal transmission. Height is best when it comes to UHF antennas as they work optimally with line of sight when sending and receiving radio signal.
The Somewhat Technical Stuff
We are far from being experts when it comes to CB radios and antennas so we will try and keep the technical stuff as basic as possible and within our knowledge. If you believe we have not addressed something or have made an error, please let us know in the comments below and we will rectify them.
Power Output of CB Radios
There are two key factors that determine how well you can send and receive your radio signal. When it comes to sending signal, the power output of your CB radio is extremely important. What you can hear is more affected by the type and location of your UHF antenna. Most CB radio units installed in a 4WD will have a maximum power output of 5-watts. This is the maximum legal power output that you are allowed to transmit radio signals. Power output more commonly varies with handheld devices. The higher the output the more expensive the handheld. We have low power output handhelds as we only ever use these around our 4WD to assist when spotting along tracks or reversing our camper trailer into tricky spots.
Receiving & Transmitting Radio Signals with UHF Antennas
When it comes to receiving radio signals or what you can hear, your antenna is going to be the most important factor. Many touring 4WDs will have multiple antennas mounted on their bull bars. Usually, a short stumpy low rated decibel antenna and a longer higher rated decibel antenna. Each type of antenna transmits radio signals in different omnidirectional shapes and patterns. With lower decibel antennas being better in hillier terrains and higher decibel antennas better in open flatter environments.
A UHF antenna signal looks like a donut in shape with the antenna in the middle of the donut. The signal of the antenna starts at its base, this is where the bottom of this donut shape begins. The lower decibel antennas have a rounder donut signal shape and the higher decibel antennas have a flatter (squashed) donut signal shape. See the graphical representation we created below to try and show this visually. If you think of the below 2D shapes as a 3D donut or torus shape (Google it to see what we mean) this gives you an idea of how the UHF antenna receives and transmits signal. As a result, a higher decibel antenna is better for long range signal transmission in flatter environments. Compared to a lower decibel antenna which provides better signal transmission in hillier or built-up terrains.
It is hard to explain this without visuals but if you think about a higher decibel antenna signal shape, when driving up a slope, the signal transmission forwards will be pointing upwards toward the sky. Therefore, if there is someone on the opposite side of this hill, they are less likely to receive your radio transmission as their antenna signal transmission pattern might fall below the higher decibel signal transmission (unless they have a low decibel antenna of course). Always remembering that the antenna signal, no matter what decibel sized antenna you might have, works best with line of sight. As a result, bull bar mounted antennas are always going to have an issue with signal transmission behind the 4WD even if using a long high decibel antenna where the tip of the antenna is just above the height of your 4WD. Any vehicle travelling in front will also act as a barrier to transmitting signal. Therefore, a low decibel antenna in most instances will provide better transmission than a high decibel antenna when the low decibel antenna is mounted on the roof of a 4WD verse a high decibel bull bar mounted antenna. This of course will not be the case in flat terrain with no interference in front of the vehicle.
As a result of the potential improved signal transmission, we chose to move our low decibel antenna from our bull bar to our Rhino Rack Pioneer Platform. This of course came with a few issues on how best to do this, we discuss these further below.
Barriers to Mounting UHF Antennas on the Roof
The biggest barriers to installing a UHF antenna on the roof of a 4WD are mounting points, clearance issues, and running the antenna cable. Aesthetically some people do not like the look of a roof mounted UHF antenna so this can also be an issue.
Where to Mount the Antenna
If you have a roof rack, like our Rhino Rack Pioneer Platform, it is extremely easy to mount a UHF antenna as you have multiple locations where you can potentially fit the antenna. Where you do not have a roof rack, you have no real options as you do not want to be drilling a hole through your roof for obvious reasons. In such a situation, a roof mounted UHF antenna is not feasible, and you will have to mount the antenna to your bull bar or another location on your 4WD. If you have a canopy or ute tray with a headboard, then you can use these locations for high mounting points.
Once you have determined that you have a decent location to mount your antenna on the roof or other high point on your 4WD, you will then need to deal with the issue of clearance.
Clearance Issues
Having your UHF antenna mounted on your roof has the obvious problem of reduced roof clearance. Getting into garages and carports or navigating around tree branches while driving will be problematic with a roof mounted UHF antenna.
The issue with being able to get into garages and carports can be easily eliminated with a folding antenna mount. The clearance problem out on the tracks while driving with tree branches is a bit more challenging. However, you can either navigate around these obstacles or in situations where this is not possible, you can fold the antenna back down. We have hit a few branches, while driving extremely slowly we must add, and have found that the antenna with the spring base has had no issues. There has been one instance where we forget about the antenna when reversing into our shed. As we were reversing slowly, when we heard the antenna hitting the gutter we stopped straight away. When we drove back out, the antenna and gutter were completely fine. This is because the antenna has a lot of play (movement) with the spring base. When folded down during day-to-day driving, the antenna sits well below our Svnty6 Fab side angled Maxtrax brackets. We use the height measurement from the top of our Maxtrax to know if we can fit into shopping centre carparks and our garage when the antenna is folded down.
Running the Antenna Cable
The other big hurdle people face with mounting an antenna on their roof (the same can be said for cables for light bars and other lights) is how you get your cable to the roof. There are lots of clever ways people have found to do this, so it will really depend on your 4WD setup and what you like the look of.
For us we chose to run the cable up the side of our TJM snorkel. This was extremely easy to do and has kept the cable partially hidden away and not noticeable. Another option that we have seen on another 76 Series Land Cruiser is running the cables up the side of the windscreen. If done right it does not look that bad however we prefer using the snorkel as the cable is more hidden. If running up the side of the windscreen you can use the black section of the windscreen, and if using black tie mounts with black cable (or black split tubing), the cable is somewhat camouflaged.
From these photos you can see how we ran our UHF antenna cable to our Pioneer Platform. We will be making some minor changes to how this works when we run the cable up for the light bar, we will fit to the front of our roof rack. But basically, we ran the antenna cable through the firewall into the engine bay from the radio unit. We then ran the cable inside split tubing along the top of the firewall to the driver’s side. Near where the bonnet bracket sits, there is an opening which we then ran the cable through to the area near the driver’s side door. From here we ran the cable up the side of the TJM snorkel. We stuck cable tie mounts with strong double-sided tape (we replaced the double-sided tape that came with these tie mounts) to the side of the snorkel. Using zip ties, we secured the antenna cable in place. We then ran the cable along the snorkel bracket into the 4WD’s gutter. To secure the cable inside the gutter, we used clear silicon which has worked an absolute treat. The antenna cable then runs up the inside of the Pioneer Platform leg, held in place with zip ties, and then to the folding antenna mount. From the front of our 4WD you cannot see any of the cable. The cable is only noticeable when standing at the driver’s side door.
When we do run an additional cable for the LED light bar, we will run both the cables in slightly larger split tubing to make sure it looks as neat and tidy as possible. After almost 12 months we have noticed that the double-sided tape has started to lose some of its stickiness from dust and water. So, we will need to replace the double-sided tape at some point. The issue here is the shape of the snorkel, so we should have used smaller cable tie mounts to try and stick these to a flatter section of the snorkel. We have considered pop riveting the tie mounts to the snorkel ensuring we use lots of silicon to keep the snorkel sealed. However, we have not yet built up the courage to do this. For now, we will replace the double-sided tape when required and keep our snorkel hole free and ensure it remains sealed.
Noticeable Improvement
Since we have moved our UHF antenna from our bull bar to our roof rack, we have seen noticeable improvements in UHF signal transmission. Communications have been that much clearer as well as being able to receive transmissions from other travellers from a far greater distance than before. Receiving radio transmissions from vehicles behind our 4WD have improved significantly when they are a decent distance from us. In our last Simpson Desert and Outback trip, we noticed a real big difference in transmission distance from the previous year since the change. We were picking up radio chatter far sooner than before which we could tell from the dune call points on the QAA Line which are spread out by approximately 5kms. Once we passed a vehicle, we would continue to hear them behind us for a significant amount of time. We have also found that if we are travelling with other 4WDs in convoy, even if we leave the UHF antenna folded down, we still have perfect communication with the other vehicles as they are nearby.
Another positive from the antenna move to the roof rack, has been a better passenger experience while touring. The passenger no longer has a UHF antenna in the middle of their line of sight through the front of the vehicle. This is not a major benefit of the change but does provide a better viewing experience out of the front of our 4WD. This move did also allow us to change the style of our bull bar to our new Offroad Creative lightweight alloy bar without having to have antenna mounting points fitted to the bar.
Overall, we have found that moving our UHF antenna to our roof rack using a folding antenna mount has greatly improved our communication experience with our CB radio. Aesthetically we prefer the look with the antenna mounted on the roof. The folding antenna mount looks tidy when the antenna is folded down, and when the antenna is folded up it looks quite good. However, if we were using a longer high decibel antenna it would look strange with a long antenna mounted on the roof. The view from the front of the 4WD is far better without having an antenna sticking out from the front of the bull bar. When the antenna is folded down, we have no issues with clearance as the antenna sits well below our Svnty6 Fab side angled Maxtrax brackets. As we were able to partially hide the cable from view with the way ran the antenna cable to the roof rack, we are extremely happy with how it all turned out. Hopefully this will allow us to remain using the one UHF antenna and not have to fit a second high decibel antenna, but time well tell so keep posed.
We purchased the Rhino Rack folding antenna mount off eBay as it was far cheaper than buying one directly from Rhino Rack. We have lost one bolt since our last big trip which was easily replaced. The Rhino Rack folding antenna mount does have a spring-loaded locking pin which makes it easy to fold up or down. To stop any movement in the bracket there is a wing nut with a spring washer that can be tightened by hand. The antenna mount is secured to our Pioneer Platform using an M8 bolt with a channel slot nut. These folding antenna mounts cost around $100.
This is the Rhino Rack folding antenna mount that we used on our Pioneer Platform.
Thanks for reading. If you would like to read our other 4WD build stories you can find them all here. To keep up to date on our future posts, please join the 4WD Adventurer Community here. For more regular updates follows us on Instagram.
The thoughts of Peter.
20/03/2023 @ 10:53 PM
Thanks for the writeup! If you’re looking for even longer range, see if you can work in a ground plane. I increased my cellular reception noticeably with an 8″ x 8″ sheet of aluminum at the base. For CB it would need to be larger, but I don’t know the size. Cheers.
03/04/2023 @ 11:06 AM
G’day Ed,
Thanks for reading and your feedback mate.
I will take a look into this and see if I can make even further improvements. Good to know it has worked for your mobile as I am looking into installing something similar to improve mobile reception.
Cheers,
Peter
23/07/2022 @ 1:39 PM
Hi,
Great articles and loads of really good info! One question that comes to mind, (possibly because I havent read all the way through the site)… What do you carry for communication Sat phone? EPIRB? have you looked into different GPS units that allow a text message service? What a bout First Aid Kits and First aid Training?
I travel to Birdsville and LOVE it out there! Great part of the world, heading back out there in September and thinking of doing a loop from Birdsville, QAA to Poppels and Hay Rive Track, Madigan Line? Thoughts? What is there to see along the way?
Cheers MIck
25/07/2022 @ 10:12 AM
G’day Mick,
Thanks for the message and feedback, much appreciated.
In regard to comms, we use the Zoleo satelite messenger. We have used this for approximately 12 months now. I have not yet written anything on the Zoleo device as I wanted to do a little more testing before putting my thoughts out there. After this trip we are about to do to the Simpson I plan on doing a write up. I like to give gear a decent amount of testing before throwing a review out there. Not one to get something and write something straight away, just to make sure I have worked out all the pros and cons. But so far, I am pretty happy with the Zoleo device. From the research I did, it was the most cost effective solution. For staying in touch, having an SOS function, and weather updates, it works well. Went with Zoleo over the Garmin inReach as it was better priced and had the basic features we needed.
On the first aid front, we carry the Survival first aid kit and snake bite kit. Shayne (my wife) is a doctor, so first aid training is top notch. We also carry a range of different medicines including antibiotics. This is another area I need to do a write up. On the first aid training, I am actually going to go through another course later this year and do a write up on this as it is extremely important and something that people might not consider.
Birdsville, Channel Country, and the Simpson are one of my favourite places. Beautiful part of the Country. We are about to do the Madigan Line, took a while to get permits to do this. Hay River Track is not one we have done yet, it is on the list, and we will do a bit of it when you do the Madigan shortly. If it is your first Simpson Desert trip be careful on fuel calculations as consumption is extremely high. As I have not yet gone up the Hay River and then back across the end of the Madigan, I can’t say much about that route. I do know that the loop we did last trip along the QAA, WAA, French and back was great. If you do that route you can then go as far as Dalhousie and return, but it will depend on how much time you have. What to see along the way? Well you will see a lot of nothing, plenty of dunes, maybe a camel or two if you get lucky. There are few points of interest depending on the route you take. We love it out there, feeling isolated and not seeing many other people.
Let me know if you have any other questions.
Cheers,
Peter
18/03/2022 @ 8:56 PM
Hey have the same antenna and moved to the roof, I can now get my mates from places we couldn’t before, I have also tested with folded down and also works really well. Did you need to get a 6.6db or happy with the 2.1 , I was concerned how the radome antenna would perform when hitting trees but as you have said and time will tell should be ok. Thanks for the write up and enjoyed the read
18/03/2022 @ 9:27 PM
G’day Ben,
Thanks for reading mate and really appreciate the feedback.
It’s interesting you bring up the 6.6db antenna. I’m actually about to buy one to test out the difference. One good thing with the GME is it’s easy to swap them around. So hopefully I’ll have one soon and give it a good test for comparison purposes.
But so far I’m really impressed with the shorty. I haven’t had any issues travelling with others running higher decibel antennas. As we prefer outback touring it will be good to try the 6.6. We’ve got a massive trip planned for late winter so I’ll be able to give it a real good test then. But it can’t be any harm carrying both and swapping depending on the terrain. As soon as I’ve done some good testing I’ll write a post on my findings.
If you are on our monthly email you’ll get an update when we throw a post up.
Thanks again for reading and sharing your thoughts mate. It’s great to know our posts are being read.
Cheers,
Peter