Antenna pass-through connectors for FWC Project M

I took delivery of a Four Wheel Campers Project M back in October, 2020. I am a ham radio operator and I want to install some antenna pass-through connectors in it. In an attempt to be "smart" about this I sent a message to Four Wheel Campers asking if they could send me a photo of a Project M frame before any coverings were in place. I want to avoid drilling into any structural members if I can help it. Within an hour I received this reply from FWC:

"Unfortunately the frame layout of the campers is proprietary information that I am not authorized to give out; such as photos or engineering drawings. I also cannot advise or assist you in doing anything to your new camper that would void the warranty. Drilling into the siding and/or structure certainly would void the warranty."

Not exactly the loyalty-building customer service I might have hoped for.

After more searching I found this link describing how someone installed an ARB awning on a FWC unit. They contacted FWC with the same question I had and received a set of very helpful photos from the company:

http://hereuntilthere.com/journal/2015/9/17/arb-awning

I sent a message to this fellow asking how he went about getting those photos from FWC - I have not heard back yet... But it would appear that if one "takes the right approach" one can get such information from Four Wheel campers. (However the above article is from 2015; company policy may have changed since then...)

I want to install the pass-through connectors in two places: at the bottom of the rear wall on either side of the rear hatch. I plan to use stainless steel plates (5"x6" with two 5/8" holes) on both the inner and outer walls, sealed with RTV silicone, to provide a sturdy mount and avoid any stress on the skin of the camper. So I do not think I will be jeopardizing the structural integrity or water proofing of the camper. I just want to know ahead of time if I can avoid drilling through any structural members if possible.

So if anyone has any advice on how to "pretty-please-asking-nicely" get a photo of the rear of a Project M frame, I would be very interested. I would also be very interested to hear from anyone who has already installed pass-through connectors (either SO-239 or Type N) in their Four Wheel Camper. Eventually I plan to create a build thread for my Project M to document my build-out, to include a complete dual-battery solar electrical system using components from Zamp and National Luna. So I hope to pay back the community for any help I may receive now!

Thanks in advance for any help and advice!

 

I have drilled the hell out of my Project M. Check out my build.

https://www.tacomaworld.com/threads/fwc-project-m-project.650163/

I may be able to help.

 

@AverageGuyTaco: thanks so much for your interest in my post! I have been following your Project M Thread since the very first post. In fact your thread was a contributing factor in my decision to purchase a Project M.

Tomorrow I will post a photo showing where I intend to install the pass-through connectors. I may also see if I can remove any of the black plastic wall covering on the inside wall and locate the structural members in the area of interest. As I mentioned above, I want to place the pass-throughs in the areas on either side of the Project M rear door, down near the bottom of the rear wall.

I also want to install some 80/20 rails inside to mount the charge controller / battery isolator unit (National Luna NL-40) and I will need to anchor those somehow, perhaps by drilling and tapping a few screw holes in the large aluminum beams in the "ledge" (or "seat"?) in the project M. I may have a question or two for you when I get to that point.

Thanks again for your response!

 

Getting the black plastic walls off is a pain. They use a strong double stick tape to hold it to the frame. Also the rear sucks. I tried and gave up cause I did not want to mess up the plastic.

I did a factory tour back in Oct 2019. I was looking through my picture and found this one. This is a prototype Project M for a full size truck. I didn’t get a rear only shot but you can make out the drivers rear in this picture.


Assuming they didn’t change it up, it looks like you have a 2” bar at the bottom, a gap of a few inches and then another 2” bar. If you shoot for that gap you could do your pass through there without going through the aluminum bars. I did this with my solar pass through. You may want to put your pass through a little further left than what I did.


Is this the type of connector you are thinking of using?

If so, machine screws would hold it to the aluminum skin no problem just don’t over torque them. Of course use some silicon or butyl tape to seal the holes.

As far as attaching stuff to the walls/bench, rivnuts are the money. I bought a tool thinking I would just need a few. I’ve ended up using a ton of them. In my Project M the wall panels are fairly flexible. I can run my hand up the wall and feel the frame. Drill into the frame through the wall and then throw in a rivnut. Practice with the rivnuts first to get a feel for how they work. It is easy to over do it and strip the threads. I did this once. Fortunately it was a M6 and I was able to tap it to a 1/4-20 thread. I primarily use 1/4-20. I ended up buying a bunch more when I went through the supply that came with the tool. The side lights I installed came with M6 hardware so I stuck with that. The tool has a nice supply of different sized rivenuts.

WETOLS 14" Rivet Nut Tool, Hand...

$39 WETOLS Rivet Nut Tool, Hand Rivet with 7 Metric & Inch Mandrels M6 M8 M10, 1/4-20, 5/16-18, 3/8-16, 70pcs Rivnuts and Blow Carry Case, Steel - WE-882

https://www.amazon.com/dp/B081GDRTXP?ref=ppx_pop_mob_ap_share

The machine screws FWC use work quite well. I’ve purchased a similar size and have used them a bunch. If they would suit your need, consider them.

Here are some pics of the bench. I measured and traced out where the framing was for future reference. I have additional pics if you need a better angle.



Feel free to reach out if you have further questions.

I am a ham as well although I don’t plan on putting a radio in the back. What is your plan for the antenna connectors at the base of rear? Just curious what you are up to.

 

First of all, thanks a bunch for that goldmine of a post above! Looks like you have placed your solar pass-through almost exactly where I want to put one of my antenna pass-through connectors. My going in plan was to put two pass-throughs, one Type N as you have shown above and one SO-239 ("UHF"), on each side (driver & passenger) of the rear hatch, pretty much where you have your solar pass through. I plan to have some stainless steel plates fabricated to serve as the mounting structure, one plate on the exterior and an identical one on the interior. I found a place called "Online Metals" that will let you order just about any size and shape of any common metal and they offer a water jet cutting service as well. Here is my home made drawing of the plates - they will be cut from a single 12"x12"x0.125" stainless steel 316 alloy plate:


Here is a look at where I want to mount these plates. Notice the blue masking tape squares on either side of the rear hatch:


A closeup of the driver's side pass-through location:


By using the type of pass-through connector shown below, with some oversized nuts, and some RTV silicone sealant, the pass-throughs themselves will clamp the plates to the inner and outer wall surfaces and eliminate the need for screws to hold the plates in place.

https://www.americanradiosupply.com/3-inch-type-n-double-female-bulkhead-connector/

Based on your input it looks like I may want to put my connectors side-by-side instead of vertically, but I think the basic idea will still work.

I already ordered and received from Online Metals some 6061 aluminum channel that I am going to use to fabricate antenna mounts that will attach to the rear jack stands on either side:

https://www.onlinemetals.com/en/buy...61-t6-extruded-aluminum-association/pid/20270

On top of each channel I will install one of these which will allow me to mount either an SO-239 or Type N or NMO pass-through:

https://www.americanradiosupply.com...l-antenna-mounting-bracket-5-8-mounting-hole/

The open side of the channel will face to the rear; the stainless steel antenna mount will be attached to the top of the channel with vertical part (with the screw holes) lying flush with the forward-facing base of the aluminum channel. The antenna mount and the channel base are almost the same width - I think I can probably use the existing screw holes to attach the mount to the channel. By orienting the mount and channel this way, the channel will prevent any rearward lean of an antenna due to wind pressure etc. I plan to put a Yaesu ATAS-100 on the driver's side and maybe a discone on the passenger side. For a 2m/70cm dual band antenna (an oldie but goodie "Cushcraft Gold") I plan to fabricate a crossbar to fit the Yakima rails out of something like this:

https://www.onlinemetals.com/en/buy...tube-6061-t6-extruded-radius-corner/pid/23490

The rectangular aluminum tube will be way, way cheaper than a "real" Yakima crossbar, and I do not need such a thing because I do not intend to put anything the least bit heavy on the Project M roof. (I will have a couple of Zamp Obsidian 100W panels up there but supposedly they only weigh about 10 lbs each.) I have always looked at that great big flat aluminum roof as an excellent ground plane for a VHF/UHF antenna!

I have a Yaesu FT-100D from a few years back that was previously installed in a 2000 Nissan Pathfinder. I also have a Yaesu FT-8100 2m/70cm dual bander that is currently installed in my 1991 Jeep Cherokee. Both of these radios have detachable face plates and there are remote mounting kits that let you separate them by 15 feet or so. I plan to try and install the radio chassis in the Project M and then run the control and audio cables up into the cab. In this way I will (hopefully) avoid getting any RF into the million or so electro-computer-gizmos lurking behind the dash of my 2020 Off Road (with Premium & Tech packages). I have read a few posts from hams with Tacomas that indicate mounting a "high-powered" (50-100 watts) radio in the cab of a Tacoma may result in RFI causing various systems to malfunction. So by keeping all the RF back in the Project M, and all the antennas back on the camper as well, I hope to avoid any major problems along those lines.

The reason I am kind of "gung ho" about making my Project M a "mobile radio lab" is that I have experienced what it is like to operate from a "radio quiet" location and the difference between that and sitting in my driveway (in Boulder, CO) is astonishing. At home in my driveway my FT-100D / ATAS-100 as installed in the Pathfinder indicated an ambient noise level (on 20 meters for example) well over S9 - sometimes 10-20 dB over S9! In the 2000's we used to go (tent) camping every year with our daughter and several of her school classmates and their families at a place called Steamboat Lake State Park, in north central Colorado. The first time I took the radio up there and turned it on I was initially very concerned that it was broken - maybe the antenna connection, maybe something else - because when I listened on 20 meters at first I heard *nothing* - nothing at all! Then I tuned around a little and came upon a weak but clear signal - from a VK7 station in Tasmania! I suddenly realized that I had been effectively trying to listen for a rare bird call while sitting right next to a roaring Niagra Falls! So instead of lamenting that I could not put up a big fancy beam antenna because I live "in town", I decided to take my radio someplace quieter!

Turns out my other hobby - astronomy & photography - is also best practiced in a remote location, far from any light pollution. So my Project M will serve as my sleeping quarters when doing some observing "out of town". There is really no way to do much astronomy if you have to stay in a hotel because if you want dark skies you will have to drive miles from any town and if you observe until the wee hours, and then have to take down all your gear and drive back to the hotel... well, "there's your problem"!

So anyway that is what I am up to. I really have learned a lot and gotten inspiration from your Project M build, so thanks again for that! I plan to post more pics and descriptions of my build one of these days, maybe after I have gotten some more of it done. I have plunked down (a lot of) money for some solar panels, charge controller, battery box, and 12VDC fridge, as well as a Goose Gear floor system and I expect by January to have most of the pieces and be well under way with the installation process. In the end I will have a 200W solar system feeding a National Luna NLDC-40 DC-to-DC charger which also includes a battery isolator (for dual battery system) and inputs for solar, alternator, and "DC" power. The DC power input will be fed by a 600W 24VDC power supply which will serve as the grid power charger. Thus I will be able to charge my auxiliary battery (probably a Battleborn 100AH LiFePO4) from solar, alternator, or "shore power" at charge currents up to 40 amps. The NL-40 is nice because it incorporates all that functionality in a small rugged package that has already been tested and integrated so to speak. (This cuts down greatly on the amount of DC cabling I have to fabricate) It automatically switches between charging sources based on a priority scheme: 1) alternator, 2) solar, 3) DC. The fridge will be a National Luna NL50 Dual-Control "Legacy" model, which will be a big step up from the trusty old Coleman ice chest. (No more constantly adding bags of ice!)

Thanks again for all the help! I will keep you posted on my progress...

73's
Steve - W0SGC

 

That is an extensive plan. Well thought out.

I agree you probably should run the pass through connectors side by side shooting for that gap in the aluminum frame. Your lower square looks to be about right. I don’t think it would be the end of the world if you did go through the frame as long as it wasn’t the edge of course.

Your cross bar idea is sound and exactly what I did for my fuelpax and trackpad mounts. Way cheaper and lower profile. The 1/8” walls on the aluminum is a bit flexible for the weight so I 3D printed some supports to go in the middle. You can see them in the pictures.



I have also heard about the RF causing issues up front. I am wondering if that has anything to do with improper grounding? I just have a duel band handheld with an external antenna on the roof for now. It’s more for vehicle to vehicle coms on trips. Some day I’d like to install a Yaesu FTM400XDR. I’ve got to stop spending money on the back of the truck first. My plan is to eventually mount the antenna on the front of the Project M over the cab. I like your idea though. Will be curious to know how it works and if you can make the remote head setup work.

Your power system and fridge set up sounds good. I have a 200w solar panel. I took it off recently to reduce weight for our trip to UT back in Oct and have not put it back on. I weighed it when I took it off and it weighed 27lbs. It is a US made solar panel rated at 9amps. It tested out at over 10 amps and under ideal conditions I was able to get that. I’ve found that we really didn’t need the panel for our use case. The alternator puts out 30amps at idle and we tend to move everyday when we are traveling. Even with a fridge I don’t think it would be necessary for us. But it is nice to have the option if we decide to do a trip where we might be camping in the same spot for several days, or if we take off on a backpack trip for several days and want to leave a fridge running in the truck at the trailhead and also at home if the power goes out. Tested out that scenario earlier this year.



https://www.ebay.com/vod/FetchOrderDetails?itemId=283431535074&transactionId=2104891576018

The DC to DC charge controllers are great. Mine prioritizes solar(if available) and then alternator. Plus it will push power to the OEM battery after the house is charged. I do not have a 120v shore power hookup either. Although if needed, I have a 30amp dc power supply at home that I can plug into the solar power pass through. So essentially that’s how I get shore power if I ever needed it as well.

I am running a battle born. I highly recommend them. They are produced locally here in Reno.

I would like to get a fridge next year. I’m still undecided on which one.

As for your hobbies, have you ever made it out to the Black Rock Desert? It is in my backyard, NW NV. It ticks off all your boxes. It is a dark sky sanctuary. The astronomy and photography opportunities are off the chart. Also, I imagine a quiet place for RF. With one exception, you want to avoid it in Aug and early Sept due to the Burning Man event. If you haven’t made it out, you should plan a trip sometime.

I am looking forward to your build progress. Let me know how I can help.

 

Dang! Somehow I "missed" your most recent post here until now! (Gotta check my Tacoma World notification settings) I am lazy (i.e. "retired") I have done quite a bit since I last updated this thread. Got my pass-throughs installed. Got my Goose Gear floor system modified to work with my CaliRaised bed stiffeners and Molle panels. Received my Battleborn 12V 100 AH battery and all my National Luna gear: NL-50 Legacy fridge, NL-40DC charge controller, and their Battery Box. I will get busy and post some pics soon!