Posted: 6/15/2014 7:05:08 PM EDT
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In the same spirit of DirtNasty's tower build thread I bring to you my shack build thread. I will update as progress continues but I've made significant progress in the past few weeks.
Ask questions, criticize me, suggest better ideas. Larger pictures and more that I don't post here can be found here: http://nullbits.foxxz.net/shackbuild Here's a basic layout of what I'd like to work towards. The upper right corner of the house will contain the shack. Ground system will run continuously from there to the rear of the house (more on that later). I'm putting a VHF/UFH dual bander on the roof. I have an HF dipole up now but its much too low. Thus I will get it 30+ ft off the ground by running it off the dual bander mount to a tree far off from the house along with a center support (marked Future Dipole). And I'm undecided if I want to eventually put up a vertical or maybe a mag loop or something else in the front pasture. 
I have an office in my house I wish to turn into my ham shack and electronics room. Located in the front corner of my house in the picture below. Its not the best place to have a shack from a grounding perspective as its about 10ft off the ground. 
One of the first things I wanted to tackle was a cable entrance. I picked up a large aluminum box with a copper back from KF7P Metalworks. I highly recommend his stuff as its exceptional quality and he will custom build boxes. It is in this box that lightning arrestors and automatic antenna switches will be mounted. So with many measurements and planning I cut holes into my house..... This is a low voltage box that clamps to the drywall on the interior wall 
Exterior hole in the house and deck was cut with a large drill bit to run 2" conduit 
Put in the 90 degree pieces and conduit 
Drill some holes in the concrete foundation and mount the box to the wall and run the conduit to it. I used some cuts of 2" conduit to space it off the concrete wall. It couldn't be mounted flush due to deck support beams that run along the wall further up and lag into the house structure. The box has the copper sheet in it but its covered by protective white plastic. 
Inside the house I finished the entrance by drilling a hole into a receptacle cover blank and using a threaded conduit end with a cover nut on it. 
So with the box installed theres grounding to be done. This is currently in-progress. Sticking with what I've read on grounding I will tie the cable entrance box to a close ground (right in front of it) as well as the house ground to tie all my grounds together. Under my deck i have run ground rods 4ft deep and spaced them every 8ft. These continue the entire length of the house and around the side to the rear of the house. Allow me to explain why... The ground at this property is shale. 4ft depth is the best you can get without heavy machinery. We used a large hammer drill to pound in all grounds. I'm 225lbs and rode the hammer drill to get them to the depths we did. In the picture below you see 3 rods in close proximity. They were the first I put in and I wasn't happy with their depth. I tried running straight down and diagonally with no better result. 
The ground rods continue around the side of house towards the back in a gentle curve. The house's electrical service and ground is in the rear corner. The house itself uses a Ufer ground due to the rocky ground. A Ufer ground system ties the ground to the rebar in the poured concrete foundation. Ufer grounds are generally great grounds. To keep potential the same in the event of a lighting strike I tie into it. 
For all connections I am using copper plates and also copper anti-oxidant paste. Again the clamps are from KF7P. I'm using 2" wide, 0.032" thick copper strap from GA Copper. The stuff is awesome. 
The ground system is still a work in progress due to the amount of rock in the ground. I can not get a shovel in the ground due to rocks and it makes it incredibly difficult to put the copper strap under the surface. I'll post updates later as that is completed... Some of this work is definitely two man work. I have to rely on friends and family to help out and I work around their time schedules to get their assistance. This is certainly the case with the roof mount for the dual bander. I am going with a Diamond X700HNA antenna (24ft long). The mount I chose is a Rohn SHRM (sawhorse roof mount). This mount is about 65 lbs (according to the shipping weight) galvanized angle iron. I felt it was more solid than the tripod mounts I typically see used. The mount itself is rated for 94 sqft load in 70 mph wind for antennas like 10 ft diameter solid dishes. The 2nd story in my house is a finished attic. Its one large contiguous room that runs the length of the house with a bathroom at the end. The bathroom was out of commission and torn apart due to a burst pipe over the winter. I also wanted to put the mount over top this spot so it was ideal. I had no issues with putting more holes in the bathroom to access the roof joists and do some reinforcing. 
The roof mount has holes to run 1/2" lags into joists spaced 16" or 24" apart. However, I did not feel comfortable running 1/2" lags into joists that were only 1.5" wide. I felt it may weaken or split the joists even if they were pre-drilled. And that was if you could hit them straight on. To remedy this we instead decided to lag into doubled up 2" by 12" boards cut in 8 ft lengths. That is... We took a 2"x12"x8' and screwed it into several joists. Then we took a second board and doubled it up over top the first one. We did this for both sides of the roof peak. Instead if lagging the mount into 2 joists (or 4 if you want to count each side of the mount) we now have support of several more joists. The additional benefit is it gives us a wide margin of error for running the lag bolts. Moreover, the joists on each side of the roof peak did not align. They were offside by approximately 3/4". Using this method eliminated this headache and we can use both the 16" and 24" hole spacings in the mount and double the number of bolts holding it to the roof. 
You can see the success of this method. We drilled a 1/8 inch "alignment hole" up through the roof so we would know where a joist was. The idea was twofold. I did not want to hit the joist with my lag and i wanted to lag on either side of it. We drilled 3/8 inch pilot holes to run the 1/2 inch lags into. 
Topside 
Ample roofing tar to keep things sealed up. The mount is solid and doesn't move at all. I had no problem hanging off it and using it to support myself as I applied the tar. 
I've omitted a large amount of information due to the time of day I'm making this post. I will reply to the thread as progress continues or as I feel there may be pertinent information I left out. |
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" Large drill Bit " Hehe you have a drill bit that big????? Daaam! Awesome Idea, but I think you mean a hole saw right??? Let me know. I need to do something like that. You have provided me a great idea to do this here. I need a way to pass through my coax through the wall to the outside instead of drilling my ceiling any more, as well as re-routing my coax from the ceiling to the wall. Did you use a junction box in the room wall? ETA: now that I read it again I see you use an old-work drywal clamp style. http://nullbits.foxxz.net/albums/shackbuild/IMG_2614.sized.jpg |
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Quoted:
" Large drill Bit " Hehe you have a drill bit that big????? Daaam! Awesome Idea, but I think you mean a hole saw right??? Let me know. I need to do something like that. You have provided me a great idea to do this here. I need a way to pass through my coax through the wall to the outside instead of drilling my ceiling any more, as well as re-routing my coax from the ceiling to the wall. Did you use a junction box in the room wall? ETA: now that I read it again I see you use an old-work drywal clamp style. http://nullbits.foxxz.net/albums/shackbuild/IMG_2614.sized.jpg You'll have to forgive my child-like writing style. I posted that at a late hour after working to get that mount up there. My mind was shot. But yes I did mean a hole saw. Since I was going straight through the wall I didn't want a box so I used a clamp style box for low voltage cabling. Its not so much a box but a frame that clamps to the drywall and has the correct holes to hole a cover plate. I left the threaded PVC adapter un-glued to the conduit. In the future it could be removed and a cover plate simply put over the box to cover it up if the cable entrance is no longer desired in the event I sell the house. |
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Quoted: You'll have to forgive my child-like writing style. I posted that at a late hour after working to get that mount up there. My mind was shot. But yes I did mean a hole saw. Since I was going straight through the wall I didn't want a box so I used a clamp style box for low voltage cabling. Its not so much a box but a frame that clamps to the drywall and has the correct holes to hole a cover plate. I left the threaded PVC adapter un-glued to the conduit. In the future it could be removed and a cover plate simply put over the box to cover it up if the cable entrance is no longer desired in the event I sell the house. Quoted: Quoted: " Large drill Bit " Hehe you have a drill bit that big????? Daaam! Awesome Idea, but I think you mean a hole saw right??? Let me know. I need to do something like that. You have provided me a great idea to do this here. I need a way to pass through my coax through the wall to the outside instead of drilling my ceiling any more, as well as re-routing my coax from the ceiling to the wall. Did you use a junction box in the room wall? ETA: now that I read it again I see you use an old-work drywal clamp style. http://nullbits.foxxz.net/albums/shackbuild/IMG_2614.sized.jpg You'll have to forgive my child-like writing style. I posted that at a late hour after working to get that mount up there. My mind was shot. But yes I did mean a hole saw. Since I was going straight through the wall I didn't want a box so I used a clamp style box for low voltage cabling. Its not so much a box but a frame that clamps to the drywall and has the correct holes to hole a cover plate. I left the threaded PVC adapter un-glued to the conduit. In the future it could be removed and a cover plate simply put over the box to cover it up if the cable entrance is no longer desired in the event I sell the house. Thanks. Good work on this setup too. I need a way to pass my coax through the wall and have been looking for ways to secure a PVC conduit to the drywall. This may be a good solution here as well.
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I remember reading about ground systems years back. I think tying into the house ground that far away might cause a ground loop. It was an article in QST about lightning protection. You might want to look that up. I could be wrong, It just came to mind while looking at your system.
Great build so far. Could that roof mount hold a light weight beam, say a 6 meter or 10 meter? |
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Quoted:
I remember reading about ground systems years back. I think tying into the house ground that far away might cause a ground loop. It was an article in QST about lightning protection. You might want to look that up. I could be wrong, It just came to mind while looking at your system. Great build so far. Could that roof mount hold a light weight beam, say a 6 meter or 10 meter? All my reading on the subject of grounding demands tying your grounds together for the reason that if you pull power from a system with a separate ground than the one you are grounded to there is a situation now where you have two different potentials between the ground systems. In the event of a lightning strike lightning is now more likely to travel along your mains to reach transformer neutral which is tied to ground. And in the course of doing so will send high voltage to everything else connected to your mains. I believe NEC also states that grounds must be tied together. For example, I also have a detached garage with its own ground. That ground hooks into the garage panel and the electrical feed coming from the house to the garage also carries a ground that connects them together. I'm earnestly trying to follow best practice. In any case your concern about a ground loop may be valid. I will just have to figure it out if it is a problem. As far as using the mount for various antennas I think it could handle anything but Rohn would really be the ones to ask. When they state the 94 ft solid working surface area @ 70 mph they also specify that it is at no more than 1 ft high off the mount. So there are additional stresses to take into account. I'm not an engineer, thats why the mount instructions have at least 3 statements about consulting an engineer for structural, wind loading, etc. I'd be more concerned about the roof than the mount 
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I hope you will have a good setup. If you are plagued by a ground loop it is a starting point.
After 20+ years I will finally have the resources to set up a good hf installation. The antenna is always the hardest part of the system. With the kids now in high school, I have the time and money. That is, before I have to start buying cars.
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Quoted:
Wow, nice place, and coming along beautifully on the radio infrastructure! Plenty of room for antennas. Better plan for the future tower, too  Pictures don't do it justice. What is the future vertical? A Hustler 5btv maybe? I still think a loop would be awesome as a horizontal antenna. |
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I don't want this thread to disappear either. Love the pics, but would love to see a sketch of your ground system.
I'd say your situation is a double edged sword; -1 to have your shack elevated. +1 having the place under the porch for the junction box to be hidden! |
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