S250 Comm Shelter Project - HAM & Military Radios

[Timberwolf22]

Thursday - More rain today = no painting.... actually it means I have to recover some things that were outside drying from being recently painted.... I see some sanding and repainting in my future.

I try not to work on electrical stuff in the rain because well I'm not that crazy....... no comments please.

So today I decided to update and then upload my electric diagrams ..... thought that might be some good reference material for me.... and others as well.

Off to the world of Visio I go.......

Friday - Today looks better...... no rain and time to start drying everything out.



Does not look like I will have to repaint anything. That CARC Green appears to dry quickly and held up to the exposure well....... no complaints here.

Everything got a final coat of paint today..... so over the next few days I will be rebuilding the shelter and things should finally start coming together. Pieces keep showing up in the mail - my family keeps wondering what I am building with all the boxes stacked in my office.



Had the lights out getting some late night work done on the S250.

I tried to download pictures that I have been taking and adding them to some of the posts where relevant.

 

[Greensteel37]

Nice project! There is a portable ground system: MK-2551 A/U. They can be found on Epay. Consists of a bunch of short galvanized stakes on a cable that you clip to the vehicle in two places. I'm getting one for my S89/M116A1 shack build.

 

[Timberwolf22]

Nice project! There is a portable ground system: MK-2551 A/U. They can be found on Epay. Consists of a bunch of short galvanized stakes on a cable that you clip to the vehicle in two places. I'm getting one for my S89/M116A1 shack build.

Greensteel - any pics of your S89/M116A1 project? I like to see what everyone else build and borrow ideas..... Ah yes the grounding discussion.

So I used the electrical recommendations for an RV... I "float" neutral and do not connect neutral to ground in the main panel... something that I would normally do in a house. While I do ground to the chassis to establish a single electrical voltage reference, the entire S250 shelter is only grounded at the connection to the actual electrical service - the L14-30 cable to the service or generator.

Now I do admit that when I run on the generator I do use a grounding stake with it..... as a habit and since the chassis ground on the generator "might" be good enough but when I can why take a risk. "Strange" things can happen when neutral and ground can provide similar voltage paths in a vehicle.... after all why possibly energize all the metal components of the box.

Response:
I was focused on the electrical power system aspect of the system and how it would be grounded. If the recommendation for the MK-2551 was for the RF system - my bad on missing that.

Yes there are additional requirements to handle the RF grounding aspect of the military and HAM radios installed in the shelter.

Will make sure to consider as I build out the S250.

I am sure my current electrical understanding will carry me thru my project.

 

[tim292stro]

Some of the stuff you've said here makes me wonder a bit if you really understand grounding outside of RF. As an Extra Class HAM, I'm certain you're familiar with the concept of the difference between power grounding and RF grounding.

Here's where my concerns come in:

1) You should not BOND the neutral to the ground if your service entrance is a temporary power cable receptacle. Your extension cord (NEC temporary power cable) will be plugged into an energy source (house, building, or generator) that has the ground to neutral bond. Think of your shelter as a "big appliance", and it should make sense. Power ground should only be used for fault clearing, so if you have a GFCI that measures the current on the neutral and hot of a circuit (like one powering your shelter), any difference between what is going out the hot, and returning on the neutral will be presumed to return on the ground - and anything over the trip setpoint that is missing from hot/neutral, will open the circuit (clear the fault). What this means then is that you want to GROUND the shelter at the point of entry.

2) All grounds should be combined into a ground system. This does actually mean that metal housings for RF or electrical equipment should be grounded to the same ground system (so any power faults can be cleared). This means your shelter's metal should be power grounded, your trailer should be grounded to the shelter, and so on and so forth. Basically any metal or conductive material that is not intended to carry power should be grounded.

3) RF ground should be much better than the electrical power system ground, a dinky 5/8" ground rod only 4' long isn't going to cut it, the ground should be thought of as a ground plane or faraday cage wrapped in a blanket of ground plane - especially if your shelter is going to have a directly attached antenna or antenna system. Think of your shelter and trailer with a single electrical power system ground as a big floating capacitive ball on rubber tires... Now if you ground the shelter to the trailer (mounting bolts in the lower tow hook brackets, metal cable tie downs to the trailer), and then RF ground the shelter to the ground with no fewer than two 8' ground rods in each corner (8 total) with flat 2" wide copper straps going to them, your trailer and shelter become lower impedance with the actual ground - this should cause your RF interference to be minimized and you should be able to reach and hear further with the same HAM kit.

All this said, if you find noise in your radio due to the power feed, you will need a noise filter on your main point of entry into the shelter - the original S-250's I've looked at come out of service come with HUGE HEMP/TEMPEST filters on the power feeds (usually good for 120db broadband suppression - about what you get cable-to-cable with LMR600 coax antenna feeds!!).

Yes this is all very confusing to most people getting into power because there is bonding (power neutral-to-ground), bonding (enclosure-to-ground), grounding (power fault-clearing), grounding (RF), grounding (ESD), and grounding (lightning protection). The good news is there are people who are working on NEC to clarify these issues - the bad news is that entire industries have set up around the certain current terminologies so fixing the terminology and correcting the understandings of purpose for each subsystem will likely literally take decades.

 

[Timberwolf22]

Just small stuff today but it adds to the project.HAM radio signs came in today.



Magnetic signs.... which of-course were funny to watch fall off the sides of the S250......yes again not one of my smarter moments.

Spent most of the time today with MadCat2 and his OT-90.

 

[Greensteel37]

The grounding kit I mentioned was for RF grounding.

 

[Timberwolf22]

Keeping it level.................. some humor.

So I started mounting shelves and other items on the walls today.

Not to be outsmarted I brought my handy level because I must admit I am a stickler for those things..... that will bother me each time I look at it = so wanted to get it right.

Electrical boxes and shelves all up on the wall and level at least my level said so that is...... next time before I start I will ask myself.... do you think the shelter is level?

Yeah that would have been good to check..... or at least to consider.

Since my 105 trailer with the S250 in it is parked out on the lawn....and I am sure the lawn is level. Missed that one..... even with my level - since this build is about lessons learned .... learn from that one. While I fill in a few holes.......

 

[tim292stro]

I remember a friend was helping a guy with a 416 trailer expedition mod. They were mounting levels on the trailer, and I managed to catch them just before they drilled the holes for the screws to remind them that they needed to calibrate the trailer to level before mounting the levels...

Yeah, if the shelter was not level before you leveled the shelves, it'll bother every time you see them.

 

[Timberwolf22]

The S250 project was put on hold for a few days while we repaired the well pipe to the house.... apparently where I live water is more important that working on the S250..... they need to get their priorities straight.



After the backhoe.......

Now that the water works in the house back to the important stuff....... S250 project.

 

[muthkw25]

Just curious but in my s250 camper build I plan on putting in a roll in bedliner to protect the bed from rust and marks where the shelter sits. Have you thought of doing that to your trailer?

 

[tim292stro]

Cribbing/dunnage might be better...

 

[Timberwolf22]

Just curious but in my s250 camper build I plan on putting in a roll in bedliner to protect the bed from rust and marks where the shelter sits. Have you thought of doing that to your trailer?

When I purchased the S250 it was already installed in the M105 trailer. I considered using the crane on MadCat2's M936 to remove the S250 but never got around to that project. I made sure to build out the S250 without any permanent connections to the M105 trailer to allow me to remove the S250 at any time.

When I purchased the Rust-Oleum Roof Seal material I picked up a bunch of it....... since I needed it for the S250 & S280 roof projects. I always thought it might be a good idea to pull the shelters out, clean the trailer and bed of my truck.... protect the metal and replace the shelters.

The S280 in my M35a3 sits on metal runners so there is a gap that allows water to run out of the truck bed and on the M105/S250 the trailer is in really good shape so I have not put that as a high priority...... something to do one day when we are bored, have both trucks with trailer in the same spot and a few hours to "play".

 

[Timberwolf22]

Gilbert was a great show........

We had good sales in the vendor arena and an even better time with Gypsy Company and all the other people we have come to "hang out" with at the shows.

I was frustrated that I had not completed enough on the shelter for the event but I brought it and set up all the comm gear.

Plenty of "WoW that's awesome" responses on the S250 helped put some perspective back into my world........ it might not be done just yet but it's really coming together and for the guys that saw it when I purchased the shelter they reminded me how much work I had already completed.



So when we arrived back from Gilbert on Sunday I unpacked the shelter and went right back to work on her......... finished all the mock up's for the computer desk area and added some more structural support for the radio desk.

 

[Timberwolf22]

More painting and more painting.......... plus a few touch ups after Gilbert.

Added the MX-2060 with PRC-77 installed on the radio table creating a VRC-64 with the antenna mount and accessories that I will install outside shortly.

I decided for fun to add up the weight of everything on that large radio table. After I did the math I then went to work on adding some additional structural support to the table. I filled some gaps with epoxy where the table sits on the frame I built and also added additional supports to the front and rear on both sides of the table.

Before extra radio table support:


With the extra radio table support installed.


Going crazy with the Velcro and cable ties to try and limit how much some of the smaller stuff moves while the S250 is "Mobile". You learn to appreciate how much thought goes into building anything mobile when you look at how "banged up" stuff can get if not properly secured.

Installed a UPS for battery backup, ran USB cables over to the radio rack.

The computer guy in me won out so at the bottom of the picture with all my paint you will see where I plan to mock up my server rack.

 

[Timberwolf22]

Since I do not have enough room on the table or the network rack for all the different radios I decided to try some creative mounting ideas.



These ammo can radio enclosures will be mounted on shelves inside the S250. Additional ammo cans will be used to house some speakers, CB Radio, scanner, antenna tuners ect...... keeps the "military look" but also helps me use up the remaining wall space.

I will paint the ammo cans the same CARC green and get them mounted up in the shelter this weekend..... gives me some more wires I will need to run as well.

 

[Timberwolf22]

The project plan

You know that thing you should create when you start a ................. project.

Well I thought it wise to dump my thoughts on the S250 project out on to paper since it was taking me longer to complete that I expected .... ok that's a lie I knew I could never meet my own timeline but it sounded better the other way.

I started the project with some notes here.... so notes there but nothing comprehensive..... I should have started off with more of a formal organized plan.... so I decided to fix that.

So I took a complete inventory of the items I still had on hand that needed to be wired or installed, what items I still needed to order and tried to put an ordered list together to help maintain some level of sanity. I failed on the sanity part of the task but the list made me feel better about the project.

So my continued lesson learn is don't jump into a project without a plan..... and once you have a plan continue to refine it. Since no plan survives first contact with the enemy continue to refine the plan as the project evolves.... projects take on a life of their own.

I had begun to run into issues as I am finishing up certain aspects of the S250 that if I did not complete something now I would be hard pressed to get back into that area and work on that task. So a complete plan allowed me to put some order to the remaining tasks that I needed to complete.

There are a few "Big Ticket" items that I still need to order and this lets me know what I am still able to complete while I wait on those particular components - mostly additional radios.

And yes before anyone asks I put the plan in Excel and the project is broken down into separate tabs each color coded of-course. Sometimes you just have to be...... yourself.

 

[tim292stro]

I have several projects like this and I think it helps one to be honest with the time and money they could commit to each project. Yes a detailed plan is good to get down and share, not just for yourself, but also so that others can check your plan and comment some of the "gotchas" they may have experienced along the way in their projects.

 

[Timberwolf22]

I have several projects like this and I think it helps one to be honest with the time and money they could commit to each project. Yes a detailed plan is good to get down and share, not just for yourself, but also so that others can check your plan and comment some of the "gotchas" they may have experienced along the way in their projects.

I totally agree with you about about understanding the commitment of time and resources to a project.

To borrow from my "Day Job"..... I am a victim of my own "Scope Creep".... the more I completed on the 250 Shelter the more I thought about the additional things I could add to make the end result even better..... that's part of the fun.

I have a feeling that a 2nd network rack, the server rack as well as the equipment to go in it likely increased the project cost ever so slightly.... at least it was gear I had lying around the home office.

Going to need a trailer to haul all the "stuff" for the S250 on the M105 trailer...... humorous I know but currently an issue. Working on external storage options for things like pole bags, antenna, fuel jugs and other indoor "clutter" items like phones [TA-312 and IP phones], DR-8 wire spools ect.....

 

[Timberwolf22]

I have been using the S250 as my HAM shack these days. Serving as NCS for my HAM Radio club every other Wednesday.... you learn what works and what does not as you actually use the "stuff". Made a few ergonomic changes to the radio layout for example.

Needed to add things like a small white-board, a wall mounted monitor..... it all increased the usability of the S250 shelter. Spent a good amount of time on software install/config and drivers on my Laptop for radio and "shack" operations.

New pictures coming to show the installation of the server rack and 2nd network rack. Have been running a bunch of additional wires as I have been using the installed systems in the S250.

New lighting has been added to let me go White or Red lighting when I want the "tactical" look.... all flat LED strips. Then other things like a movable desk lamp made life more comfortable in the S250.

Modified my external hookups to include an Ethernet uplink port to allow me physical LAN connection to the house or anywhere else I am parked.... the S250 shelter is really good at keeping signals out of the box.... not so good for Cell Phones or WiFi when the box is all buttoned up. Will need to fix the cell phone signal issue in the future.

I have been filling old screw holes in the S250 internal walls...... and then touch up painting.

Currently installing a multi-coax passthru for all the extra antenna's that I want to be able to deploy when I park the S250 in semi-permanent mode and I can raise some higher antennas.
http://www.mfjenterprises.com/Product.php?productid=MFJ-4601

 

[ibhiii]

I have been planning a slimier build for the last three years. I almost have all the key parts to start the project. Glad you beat me to this. Your much better at documenting these projects than I. You might consider Broadband-Hamnet Node for a point to point WIFI bridge in the field rather than a wired network drop. You are doing some really great stuff here.

-KC3DCJ