Barn Door for JK factory hardtops
- Thread starter jscherb
- Start date
jscherb
Expedition Leader
Here's a photo of the barn door in a factory hardtop compared to a photo with the Safari Cab rear panel setting against the factory hardtop to sort-of simulate the look of the panel on a hardtop.
BTW, this panel could also be installed as the rear panel of a factory hardtop with a little fiberglass surgery... removing the factory panel and transplanting this one in its place.
Also, based on the look of the actual fiberglass parts, I've updated the concept drawing slightly (changed the radius on the top and bottom of the rear opera windows), and I've also drawn in a second Alpine window on each side of the roof.
BTW, this panel could also be installed as the rear panel of a factory hardtop with a little fiberglass surgery... removing the factory panel and transplanting this one in its place.
Also, based on the look of the actual fiberglass parts, I've updated the concept drawing slightly (changed the radius on the top and bottom of the rear opera windows), and I've also drawn in a second Alpine window on each side of the roof.
Volkswagenguy
New member
Man the progress is amazing. Makes me want to get rid of my WK and pick my long wanted JKUR, I guess I can wait to see if someone picks this up and produces it.
jscherb
Expedition Leader
I haven't really thought about getting it to production or finding a company that might be interested, I've just been focused on completing the prototypes.
jscherb
Expedition Leader
Here's a rough idea of what Tom and I are thinking about for mounting accessories on the heavy-duty hinges. We've still got some work to do on design details, so consider these just concept images for now.
Here's an example of a Hi-Lift carrier mounted to the hinges:
If you wanted to carry more than one thing back there, we're thinking about a base plate with a grid of mounting holes. The base plate bolts to the hinges, and then the accessory carriers bolt to the base plate. For just the Hi-Lift, it would look like this:
Accessory carriers can be bolted to the grid, in any combination that fits and clears the spare and the tail light. Here are a few examples showing other stuff mounted. On the left, some rubber "Quick Fist" clamps mount a military shovel. In the center, a bracket mounts an ammo can, perhaps containing a recovery strap. And on the right, a jerry can.
Mounting things as wide as a jerry can, or mounting a Hi-Lift plus an ammo can might cause interferance with the tail light when the tailgate is fully open, so for some combinations it might be necessary to install an optional stop in the hinge that limits the tailgate opening to 90-degrees. We made Tom's hinges to overcome that problem, they're designed with a wider swing than the stock hinge geometry so a jerry can will fit just fine on Tom's hinges, but for the heavy-duty hinges with the stock geometry a stop might be necessary for some combinations of accessories.
We're also thinking about a few other accessory carriers that would bolt to the grid system, such as a Rotopax container holder.
We're about to make up a prototype, but before we do, is there anything we've overlooked? And any other items that you think we should allow for mounting to this system?
Here's an example of a Hi-Lift carrier mounted to the hinges:
If you wanted to carry more than one thing back there, we're thinking about a base plate with a grid of mounting holes. The base plate bolts to the hinges, and then the accessory carriers bolt to the base plate. For just the Hi-Lift, it would look like this:
Accessory carriers can be bolted to the grid, in any combination that fits and clears the spare and the tail light. Here are a few examples showing other stuff mounted. On the left, some rubber "Quick Fist" clamps mount a military shovel. In the center, a bracket mounts an ammo can, perhaps containing a recovery strap. And on the right, a jerry can.
Mounting things as wide as a jerry can, or mounting a Hi-Lift plus an ammo can might cause interferance with the tail light when the tailgate is fully open, so for some combinations it might be necessary to install an optional stop in the hinge that limits the tailgate opening to 90-degrees. We made Tom's hinges to overcome that problem, they're designed with a wider swing than the stock hinge geometry so a jerry can will fit just fine on Tom's hinges, but for the heavy-duty hinges with the stock geometry a stop might be necessary for some combinations of accessories.
We're also thinking about a few other accessory carriers that would bolt to the grid system, such as a Rotopax container holder.
We're about to make up a prototype, but before we do, is there anything we've overlooked? And any other items that you think we should allow for mounting to this system?
jscherb
Expedition Leader
A pull pal is a good idea, thanks.
I haven't seen anyone try to carry propane on the back of the Jeep, what's the reason for that? Is it just to get it out of the cabin while transporting it to the camp site?
A 5lb. propane tank is about 8" in diameter, which certainly could be carried on this rack, but the tailgate would have to have a stop at 90-degrees because of interference with the tail light when the tailgate was fully open.
jscherb
Expedition Leader
That's an interesting idea. What dimensions would it need to have to be effective?
Jurfie
Adventurer
Someone in the Ursa Minor J30 thread posted a photo and product used to mount a propane tank outside. I never considered it, but I like the idea of moving flammables to the exterior rather than carrying it inside; plus it would free up more interior space.
Yep. I carry propane outside for camping because the bottle may vent if the pressure gets too high. Being in Florida the last thing I want is to come back to a car full of propane that vented because of the temperature.
Here is a link to the setup I did have, I have moved away from it just because the strapping it down was a pain in the rear end.
http://www.expeditionportal.com/forum/threads/95361-Propane-tank-storage?p=1282618#post1282618
In this thread the gentleman has a propane tank on the hardtop and on the tire. Post 15 shows both
http://www.expeditionportal.com/forum/threads/127199-Trans-America-Trail-and-Beyond?highlight=trans
AT and powertank both make brackets for storage on Jeeps and trailers so there is a market out there.
jscherb
Expedition Leader
Someone in the Ursa Minor J30 thread posted a photo and product used to mount a propane tank outside. I never considered it, but I like the idea of moving flammables to the exterior rather than carrying it inside; plus it would free up more interior space.
Thank you both, that's very helpful info.
jeff
Dan Grec
Expedition Leader
Someone in the Ursa Minor J30 thread posted a photo and product used to mount a propane tank outside. I never considered it, but I like the idea of moving flammables to the exterior rather than carrying it inside; plus it would free up more interior space.
In most places, it's illegal to carry a propane tank in the passenger cabin of a vehicle.
-Dan
FYI, 146 MHz is VHF and 440MHz is UHF, the popular HAM frequencies for vehicle comunications.
I'm not an expert yet on the technical side of antennas, but there are (3) popular waves that I know of (5/8", 1/2", and 1/4"). 1/4" & 5/8" require a ground plane to be effective. 1/4" I believe requires about 18" radius of a good ground plane (metal) around the antenna. 5/8" requires too much I believe to even fit on a normal roof. 1/2" requires no ground plane. In the HAM universe, they say that only the dedicated HAMs drill into the roof's of their cars lol. That's why police cruisers have their antennas drilled into the roof & trunk lid. Better radiation pattern.
Here is a picture showing the radiation pattern of various mounting positions (Obviously, the center of the roof is the best. Most people suffer on the Wrangler because they mount (me included) the antenna on the corner. This equates in very poor reception):
Here is a great quick article on antenna placement:
http://kv5r.com/ham-radio/mobile-antenna-placement/
"We have provided you some guidelines for mobile antenna selection. When selecting a mobile antenna, there are a number of factors that significantly affect the ultimate performance of the antenna. Gain requirements, electrical type, ground plane availability mounting style and placement, coaxial type and loss ratings, physical size, appearance, and surrounding environment are all issues that must be addressed to ensure the maximum performance from a mobile antenna installation. The electrical type or design of the mobile antenna is commonly referred to in terms of its dimensions in terms of wavelength: 1/4 wave, 1/2 wave, 5/8 wave, etc. Each electrical type has a specific radiating pattern to be considered when selecting a mobile antenna. For example, the signal radiating from a 1/4 wave antenna is directed more vertically, thus making it ideal in urban environments where buildings might obstruct the signal. The design of a 5dB collinear mobile antenna is designed to direct the signal more towards the horizon. This type of antenna is ideal for geographically flat regions where signal coverage is sparse.
antenna centered in roof of carGround plane availability is another critical factor in mobile antenna performance, and must be considered when determining the location and type of the antenna. Ground plane requirements vary given the type of mobile antenna and the frequency of operation. A typical 5/8 wave antenna at 150 MHz requires a ground plane of at least 42” in diameter. At 450 MHz, 15” is required, and 800 MHz, a minimum of 8” is considered sufficient.
In terms of mounting mobile antennas on a vehicle, there are five general locations: the roof, front fender, rear fender, trunk and rear window glass (although other glass mount locations may be used). Of these, the center of an automobile roof is considered the best for mobile antenna placement, followed by the center of the trunk lid, the fenders, and then on-glass mounting. This ranking is determined by the amount of ground plane provided by the positioning, and clearance from obstruction (i.e.: the roof line), and is the reason the center of the roof is considered the ideal mounting location, provided the roof is metal. The diagram above illustrates the effective loss (at 800 MHz) due to insufficient symmetrical ground plane."
What I take from the previous article is that 1/4" wave is ideal for city and mountanous environments because it radiates more upwards. 5/8" wave is good for open landscape because it radiates more sideways.
For more information on the subject specifically related to the Wrangler, check out the following thread. There's a lot of information in post #1 explaining how poor the Wrangler is for antennas and how to get the best out of what you got:
http://www.jk-forum.com/forums/jk-c...-mount-your-cb-ham-antennas-your-jeep-227276/
Another article showing the side view of various wave antennas on various frequencies - http://www.hamradio.me/antennas/repeaters-antennas-trigonometry.html
Side view of radiation pattern (1/4" & 5/8") on VHF frequencies:
Side view of radiation pattern (1/4" & 5/8") on UHF frequencies (disregard the green plot):
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