Home antenna build for TV

Jim O'Dell

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2,783
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Between Aledo and Fort Worth, TX
OK, I'm through with Charter TV. Last couple months, price has increased a little with another increase this next month. All in all about 10 dollars, they say mostly taxes. At the same time I noticed that several channels dropped out. I called last week and evidently they had me on a plan level we had not been paying for, so 40 channels all in all dropped. So to get our internet and the channels we have had for 25 years or so, it would cost about 135.00 a month plus taxes. That is no premium channels!! Ain't gonna happen. We have been with Charter for almost 30 years, and this just ticks me off.
I made a prototype of an antenna last week, installed it Friday late, and I'm getting 39 OTA channels in digital HD. This design: http://www.mikestechblog.com/joomla/misc/hdtv-antenna/127-build-high-gain-hdtv-antenna-plans.html I cleared off the foreign, to me, language stations, and I ended up with about 29 English speaking channels. Not bad. Only issue is I need to supplement for sports. Still looking into that online.

So I now need to rebuild the antenna with materials that won't disintegrate so fast. The plans for this antenna call for PVC pipe and aluminum. I dislike the idea of mounting the feelers on a curved surface, so thought I might use some PVC trim material like this: http://www.homedepot.com/h_d1/N-5yc...&keyword=PVC+trim"&storeId=10051#.URAV1zmn9pU The aluminum angle and flat material in the original instructions are expensive, so I'm wondering if I can use the PVC material for those parts as well.

My question to you is, if I rip this material into thinner strips, how will it hold up? I could seal off the cut edges with caulk if need be. Can you think of another material that would be better and still be cost effective? Here is a drawing of my version of the antenna: hd antenna.jpgThe piece on the center outside would be 2 1/4" wide and about 72" tall. This is what the 20 feelers are mounted to. The horizontal pieces of the boxed area would be 1 3/4" wide and about 24" long. The vertical parts of the box about 1 1/8" wide and 68" tall. The parts, except for the 68" vertical parts of the box, will be held together using long stove bolts that attach them to the aluminum mast(s) so everything is secure. The small animal fencing will be held on to the boxed parts with stainless steel machine screws, washers, and lock nuts on the pole side of the 3 horizontal members. Not sure how to attach the vertical parts of the box. They may go behind the fencing material and be held together with the stainless steel screws, sandwiching the fencing material between them and the horizontal parts.

Any insight you can offer on the materials I'm thinking about or alternatives would be greatly appreciated! Jim.
 
Cool link..

I think the main thing I'd be concerned about with that is whether or not the PVC would be strong enough for the backing part. The fence mesh could catch and hold a fair amount of wind so there could be a reasonable amount of toque on the connecting points.

I was also thinking there might be some additional grounding effect but having read some that doesn't appear to be the case, so mostly something strong enough looks like all that matters. Maybe some pieces old bed frames? You can often find those free if you did around a little (they make great welding practice, and I build my Dc cart out of them for $0)
 
Ryan, your concern that the PVC material wouldn't be strong enough, do you mean being attached at the three points it would not stay straight. That it would bow or otherwise distort? Do you think 2" PVC sch 40 pipe would be stronger? Or is it you fear that the PVC trim would flex in the wind? The aluminum and steel masts flex some with the current cobbled plywood version I'm using, but not the plywood part, thus the reason I'm considering using 3 guide wires to stabilize that. I guess I should have tried it in my attic before mounting it on the pole to see what would happen. Maybe I should try that before going out to purchase the parts to rebuild it, just to see if it picks up from in there or not. If it did, I could just use it as it is as I don't think it would deteriorate in the attic. I appreciate your post! Jim.
 
Yeah mostly that it would flex and twist if outside in the wind. You obviously don't want the reflector to contact the antenna itself so I think that the two parts should be fairly rigid to each other and if the supporting material allowed enough twist I think that would be a possibility. Of course flexing also introduces stress into other areas so that could perhaps lead to quicker failure of some of the connecting points or or parts.

Note: I'm not completely 100% sure I'm thinking of the same trim as shown in your link, but if it is it was fairly floppy over any length (I could be wrong there, wouldn't be the first time :D).

For outside I'd use schedule 80 instead of 40, when exposed to sun the schedule 40 gets brittle in 6 months to a year or so and would be more likely to shatter. From what I can tell the reflector part doesn't have to "do" a whole lot so you should be able to guy wire it down well without affecting the performance.
 
Good info Ryan. Like I said, I didn't find it the day I "kinda" looked for it. All I could find was the light weight foam core trim that comes in white and wood grain finishes. I don't need something that will twist. But the issue of the PVC pipe getting brittle over time bothers me too which is why I was looking for an alternative. The guy that posted the tutorial on how to build the antenna I built used black PVC. I haven't found that yet. I wonder if it would be better in the elements? I may break down and look for some plastic pieces I can mount the feelers to and then mount to the aluminum pipe, then to the steel mast. I thought I might be able to use the plastic pieces that came off the antenna that was up there. but the distance between the feelers is too far. Need to look at them again and see if I can cut off the old par and still use them. Worth a shot. Thanks for your help! I'll still try to find the stuff to actually look at before I decide which way to go for sure. Jim.
 
The black should be ok as far as brittle goes as well, its mostly just the white stuff that turns into shards of despair. HD used to have the black in sewer section, but last time I looked they seem to have moved to more brittle and annoying to work with materials :rolleyes:. Any decent plumbing supply should have it though.

I don't think there is a real functional difference (in this case) between the gray and the black PVC as you're just using it as an insulator so I'd go with whatever is cheapest/easiest to find :D
 
Ok, I went ahead and sent a message to Aztek asking how it might fair in this situation, but I think I know the answer, so I'm investigating alternate ideas. I think I may have found something that will work. UHMW is UV resistant, doesn't absorb moisture and is supposed to be great for outdoor use. I can get a small plank and cut it up and attach to the square aluminum tubing for each of the 10 feelers. Might have to use the aluminum for the reflector mounts. This might be a few dollars more expensive, depending on how much the UHMW is, but this may be the best route to go. Any ideas? Are there any holes in my thinking? Let me know! Jim.
 
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Just make sure the connection points for the fingers don't contact anything conductive connected to the reflector; I think that's probably why they used a pipe to begin with as you have a nice built in stand off in the pipe itself.

I'd suspect that Sched 80 would be a lot cheaper than UHMW, unless there is a secret source of cheap UHMW I haven't found ?? :D
 
I know the pipe would be cheaper, and I may have to go that route. I just dislike the idea of mounting the feelers on a curved surface. I can get a 1/2 X 4" X 48" piece of UMHW for 20 bucks at Peachtree. If I could find a free shipping code that would save the extra shipping expense. I could also save a little and not use the flat bar to sandwich the screen to the angle piece. I could use just the screws and large washers instead. That even beats the idea I had of using cheap T-track instead of the angle piece. Although, I like the T-track idea as it allows for easy positioning of the screws that stretch the reflector screen to keep it flat. Maybe I can find a cheaper source for three 24" pieces of T-track. Still lots of ideas floating out there. One will take hold and work before long! Jim.
 
Well, scrap everything :eek: :doh::doh:...well, almost everything. As I was looking at pricing, I was going from 55-65 dollars for the antenna to close to 95.:pullhair: Not going to happen. So I started looking through the internet for ideas and saw something that reminded me...I've got a gazillion cinch blocks in the attic with my old HO train stuff. Yep, I can make them work. So Azek trim, UMHW, and all that are out the window. I can mount these directly to the 1" square tubing I'm using for part of the mast. It gives me the flat surface I want, and the block is insulated. I'll use some 3/4" aluminum angle for the reflector part and drill holes and use some screws and washers to keep it tight. I'll get out for around 50 bucks. Thanks Ryan for bouncing ideas with me! I'll post when I get it all put together. Jim.
 
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I'm still going to try the antenna as it exists in the attic to see if I get reception there or not. I'll scrap the rebuild if it does. I went ahead yesterday afternoon and modified the cinch plates, so they are ready. I had to work today at the new job, so will wait til next weekend to take it down and try the attic so that I'll have 2 days to do the rebuild if it doesn't work in the attic. I'll post back with what happens and some progress pictures. Jim.
 
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