My NN1G 30mtr QRP Rig

Back when Dave Benson’s Small Wonder Labs was still in business, I purchased one of his kits and later assembled it and put it in one of my home-built clamshell cases. Like everything else I built, little was done to hide the home-brew aspect of the rig, even if it wasn’t a scratch-built project. It’s an excellent rig for 30mtrs, and worth having if you find one in any band available.

Click on the following images to expand them.

I’ve been asked about the clamshell cases I use, and thought I’d give some ideas I use in making them. First, ANY sheet metal brake will bend aluminum, and the only restriction you have is to ensure your brake is wider than the sheet you wish to bend. Adjusting the brake is the next step, if possible. For those who either can’t buy or otherwise get access to a brake, all is not lost. In nearly every home-improvement store, you’ll find hand tools called SHEET METAL TONGS or HAND-BRAKES. You may find these in either the HVAC ductwork or siding departments, and sometimes where the rest of the hand tools are. The best are made by MALCO, and are usually recognized by their distinctive chrome color with black rubber handle coverings, and cost around $50 for the smaller version, or $80-90 for the larger version. You’ll notice the edges of these line up nice and accurately, ensuring a clean, accurate bend in your metal. It can take a bit of practice to get used to doing this, so don’t practice on your rig material….get some scrap and try them out first to get a feel for how to use them. I generally use these on small project boxes, and usually with lighter material for the tops and bottoms. I nearly always use 16ga material for the front and back, as that makes things more rigid. I should point out that you can also procure these in many flea markets for less than $10, which is downright cheap! I’ve bought several this way. You can also try the hand tongs sold at Harbor Freight, but you might have to use lighter sheet metal if you do. I haven’t tried these, but they remind me of the old PEXTO brand, and may not handle heavier metal unless you have the “kung-fu-grip”. Just a thought.

Another handy tool to have is the #5 Whitney Punch. These are standard tools for almost every sheet metal worker or HVAC technician, but they can be expensive at around $100-120, depending on who is selling them. I hear that Harbor Freight has them for much less, and this is worth looking into for the home constructor. A Whitney Punch cuts a nice hole and doesn’t drift like a drill bit, but at this price range, some folks may decide to just stick to drill bits. I’ve only seen one at a flea market, and some fool painted it with black stove paint and tried to tell me “That’s the natural finish!”  I told him I already had one and had seen hundreds over my career, and none of them were black. I got it for $3, but it took a long soak in a small bucket of Acetone to remove the crappy “finish” he’d installed, and it still barely functioned.

If you look at a blowup of the internal view, you can see the self-tapping sheet metal screws I used to hold the clamshell case together. These are #4 x 1/2″ long flat pan head screws. You can pre-drill the holes if you clamp the front/rear panel in place with a Vise-Grip plier and drill them, but I hold them by hand and use the smallest punch in my Whitney. Remember I said the punch doesn’t drift? I can punch the hole where I want on the bottom/top, and use that hole as a guide to punch the front/rear panels. Now you know why I love this tool.

One more thing: See those nice tiny pots in the front panel? Those are Clarostat and Allen-Bradly pots, and they are prohibitively expensive to purchase new these days. I’m likely to replace them with more common pots and save them for my smaller builds, as they’re also hard to come by.  Next to the main tuning knob is the RIT control, which was purchased from Dan’s Small Parts And Kits, and to the left of that is a transformer mounted on the filter “Q” pot, for adjusting the filter bandwidth. I haven’t hooked up the filter yet, and may decide to install one of those cute little 2-pole filters and a small switch from Dan’s as well. They’re small, work beautifully and are a real nice bargain.

I hope this gives others some ideas about packaging their pet projects. I tend to not go for the “professionally-manufactured” look, as I prefer others to know that home-brew can be just as good looking as it is functional. Besides, aluminum doesn’t rust, and scratches really don’t bother me.

73 de Mike, KC8LCY

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