The 40m attic dipole

The 40m attic dipole is the antenna that allowed me to get on-the-air. No restrictive deeds here, just an XYL that doesn't want to see any wires outside and didn't go along with my plans for an 80m dipole accross the back yard -- that would have been a sweet antenna up at 60+ feet.

Of the 66 feet of wire, about 38 feet are straight and horizontal. The rest of the wire bends back at an angle and down towards the eve at the front of the house. The top section is about 2 ft. lower than the ridge (maybe 25-30 ft. above ground) -- I wanted to stay away from the metal plates at the peak, though I may tie the center a little closer to the peak one of these days.

The tricky part was routing the 450 ohm ladder line from the attic to the basement. I opted for the ladder line since I wanted to be able to use the K2's ATU to tune-up on multiple bands and I wanted to keep line losses to a minimum since I can put out 15w max at this point.

OK, now for the pictures!

Here's a wide shot showing the center insulator. Nothing too exciting about this one.

Here's a close-up of the center insulator and the connections to the ladder line. The insulators for this antenna were cut out of 1/4" plexiglass -- it's black because that's what I was able to scrounge from the local glass company, Franklin Glass.

And the insulator at the bend of one side of the dipole. Everthing is symetrical from one side of the dipole to the other.

In the picture below, the end of a dipole leg with insulators at the end and cord to hold it in place. The only real trick here was making sure I didn't fall through the ceiling and land in the bedroom, hi!

Now for the fun part, routing the ladder line. The stand-offs were cut from 1/2" PVC electrical conduit. Here's a picture of the first bend, and another showing the strait shot to the end of the attic.

Here's the hole in the "Thermo-Ply" sheathing through which the line entered the attic space over the garage. I live in a Toll Brothers house which is built instead of using plywood with this stuff that looks more like shiny cardboard. I'm suspect this may do some funky stuff to the antennas radiation patterns -- doh!

I didn't show the feed-line running through the garage attic, but you get the idea. In the garage proper, the feed-line is tie-wrapped onto the back the white PVC pipe show below. This pipe is part of the radon mitigation system. The gray conduit contains cable TV runs and network runs that I installed a couple years back. And finally, we're getting towards the basement...home free? well not quite...
 

Between the garage and my shack, I had to avoid duckwork, pipes, and everything else as best I could. I'm continuing to use the radon mitigation pipe and more pvc stand-offs here and continued along running between the natural gas pipe and the HVAC ductwork, but not getting too close!

   

Here is a tight squeeze between a busy section next to the furnace and hot water heater. I tried to split the difference the best I could and used tie- wraps to center the feed-line in the space available.

Home free -- only a few more bends to go. My shack is on the other side of the wall. I used two large PVC bushings to trim out the 3-1/2" hole in the sheetrock. My power supply was set up on this side of the wall to remove fan noise from the shack, but I have since moved it into the shack (I use headphones so the fan noise isn't that big a deal). The ground conductor is 1/2" copper refrigeration tubing (the somewhat flexible stuff that comes in a coil) soldered to a section of straight copper tubing that is attached to the wall behind the table in my station. I added some braided strapping to improve the soldered connection...not sure if it was necessary, but they can't hurt.

Once in the shack, I connect to a 4:1 balun -- built following the W1CQ instructions.

And a short (~10") RG-58 jumper and we're at the rig! Finally! The rig is the an Elecraft K2 with the following options: 160m, noise blanker, audio filter, ssb module, internal battery, and the internal automatic antenna tuner. It's the ATU and the feedline that makes it easy to tune-up and go. So far I've made contacts on 20m and 40m (I've tried on 80m, but had no luck. The 17m and higher bands seem to be pretty deserted so no contacts there either, though once the sunspot cycle up-swings things may get better -- that's the hope anyhow.

Here's the shack in a picture taken before things started getting too cluttered.