Friday, February 20, 2009

Cancelled the Satellite Subscription :)

I am happy to say that I cancelled my StarChoice satellite subscription yesterday. This week of testing has gone very well. On Sunday I noticed that with clear skies and good weather, that my reception was suffering. I ended up building a new temporary mount and put it higher on the peak of the roof. Reception this week has been great despite the variety of weather. I think I know now where I need to mount it permanently and am working on the how. Also this week, I managed to scoop a refurb Hauppauge HVR-1600 for $25 to use as a second tuner, so SnapStream is now able to record 2 ATSC broadcasts at the same time.

Saturday, February 14, 2009

Testing 1...2...3...

I finished assembling the GH10 today. I am still considering how to best mount it permanently, but for now I have it hanging from the eavestrough at the front of our house. To minimize sway, I hung a hanging basket with a couple bricks in it from the bottom. Reception is great with all major Buffalo networks coming in at 100%.

Friday, February 13, 2009

Work in progress...

I purchased some 1/2" CPVC tubing to build the frame today. CPVC is much more rigid (and expensive) than standard PVC/PEX. Even at 1/2", the frame is very sturdy - I placed a board on top of the raised section and stood on it. Drilling the holes for the colinear rods was probably the biggest challenge. I think I did a fairly decent job of keeping them on a flat plane, but it was tough - even with the drill guide (below), particularly the 4 holes that had to go through the PVC Ts. A drill press probably would have made the job easier. Applying PVC cement to the joints and connecting all of them at perfect right angles took some care as well. This project is definitely a more complicated build than the standard SBGH described on the forums, which uses steel fencing as the reflector.

Tuesday, February 10, 2009

PVC frame for GH10

I have been tinkering with ideas for how to best design the frame that will hold the elements and colinear reflector rods. This is what I'm thinking so far. I'm thinking of 3/4" CPVC for rigidity. The reflector rods will be drilled through the taller frame. I might consider 1/2" PVC for the upper frame that holds the elements.

Btw, I went back to Metal Supermarkets yesterday and picked up a short piece of 1/4" aluminum to complete the reflector rods.

Sunday, February 8, 2009

90 Degrees of Separation

I found a short piece of 3/4" PVC in the basement, so I decided to test the "Versatile Drill Guide" (below). This simple tool made it quite easy to drill perfect 90 degree holes through the center of the tubing. I anticipate this will really come in handy when mounting the 20 colinear reflector rods. As you can see in the video below, the result is a tight fit, where some force is required to position the rods, which will make the milimeter tolerances of the rod separations easier to attain.

Saturday, February 7, 2009

On a Bender

I did some more work on the Gray Hoverman today. Pictured below are the zig-zag elements, attached to the jig I built out of plywood. On the right are all of the colinear reflector rods (all but one - see below), as well as the cutting jig I built to cut the rods. I found that bending 1/4" aluminum rod using a homemade jig on a piece of plywood is not an exact science. The angles invariably have a curvature to them and as a result, it is difficult to adhere to exact measurements down to the mm. I don't know whether ultimately these slight variations will have much impact. My 3 and 6 year old boys are pushing me harder on this project than myself - they keep asking to go out in the garage to work on the 'Super-Antenna'.

Friday, February 6, 2009

Measure twice - cut once...

I cut all but one of the colinear rods for the reflector on my GH10 project this evening, but came up a little short. Note that there is very little to spare in 36' (3 x 12') of rods (about 20cm overall). I did the math - it is possible, but you have to plan your cuts wisely. My mistake was back in the parking lot when I cut the rods to fit in the car. I guess I'll be making another trip to the Metals Supermarket for another $4.14 worth of aluminum. The way I figure, I will likely want to build a small antenna to point at Toronto at some point too, so having extra will come in handy. I did all of the cuts with a hack saw and a jig that my boys and I put together to ensure accurate measures.

Versatile Drill Guide

I found a tool that should prove invaluable in drilling straight holes in PVC tubing or wood to hold the 1/4" aluminum colinear reflector rods in place at Lee Valley.,180,42311,42321

Metal Supermarkets

Yesterday I went to Metal Supermarkets, where I picked up 36 feet of ¼ inch aluminum round rod for CDN$12.43

Metal Supermarkets:

The Gray-Hoverman Experiment

I am now planning to build one of these (GH10):

Jed’s Gray-Hoverman HDTV UHF antenna:

Antenna Research

I did a little more research and reading – mostly here: Forum : Antenna Research & Development:

Antenna Gain Comparisons:

Coat Hanger HDTV Antenna

On the weekend I made one of these, put it up in my attic and received 13 digital channels – mostly from Buffalo (50+ miles away):