: Best Metals for Antennas: Performance, Soldering, Welding, Bending, Working
2011-07-12, 10:45 AM
majortom, I have an album posted which shows some of the basic steps used. I have since improved on those techniques, for example I press the steel rod into the channel to form the 'U' shape as opposed to hammering. Anyway, I am going to make some further improvements on my next effort which I will document with pictures. It produces a tube with an overlapped join but is quite rigid. It needed fiberglass rods thru partways on the longer reflectors to give them some weight bearing strength but this time I'm going to try doing a double roll on the longer ones to add strength. The major benefit of this is the low cost of material - I used .010" aluminum flashing sold in 10' rolls at Home Depot for $12. One roll produced enough for my GH10n3. I want to find a way to speed up my fabricating technique since this time I'm going to build a DBGH.
2011-07-13, 03:23 PM
unclesam where did you find your driveway markers? I've only been able to find them for $5 or $6 which seems a little expensive x13 or x26 for a DBGH.
I've checked rona, home depot and walmart.
2011-07-13, 04:26 PM
I just saw them today at my local Home Depot....$1.99 for a 4' length.
2011-07-13, 04:58 PM
Even cheaper, (but a bit heavier because they are solid) are 3/8" diameter X 4 ft fiberglass electric fence posts at $1.29 at Tractor Supply, if you have one of those stores in your area.
(Actually theyre a hair more than 3/8" in diameter. With my new digital calipers, I get 9.66 mm to 9.85 mm.)
2011-07-13, 05:57 PM
Has anyone succeeded in using 1/4 inch soft copper tubing for the active elements of a GH? Supposedly, it can be bent with a half inch radius.
I have a Stealth Hawk up on my roof, but I'm getting way too many drop outs, even when the weather is perfect and the trees are free of leafs:
So I bought a 20 foot roll of 1/4 inch soft copper tubing to make a WildWillie HiVHF+UHF Hourglass Bowtie-In-Loop:
However, Nickml's GH2n with NARODs gets twice the gain, and doesn't look all that much harder to build:
So, I'm wondering, should I return the 1/4 inch copper tubing and get some 8 gauge copper wire instead?
In case anyone cares to look, here's my TV Fool:
The only stations I care to receive are all LOS and in green at 172-176 degrees.
2011-07-13, 06:26 PM
You might want to look at unclesam's approach using 1/4" soft copper on Instructables.com
2011-07-13, 11:12 PM
Unclesam cuts it, flattens the ends, and then rivets it together? As much as a genius as he is (and he is), this looks like trouble waiting to happen - too many spots to corrode. Though, I could use solder instead of rivets. Hmm.
2011-07-14, 12:18 AM
So, I'm wondering, should I return the 1/4 inch copper tubing and get some 8 gauge copper wire instead?
Or 6 gauge, if they have it. Solid copper wire is much easier to straighten than tube.
2011-07-14, 06:07 AM
Though, I could use solder instead of rivets. Hmm.
Yes. Soldering would be much better. Otherwise corrosion would definitely be an issue (unless you could find all copper rivets).
Otherwise as 300ohm says, solid copper wire really is a lot easier.
2011-07-14, 03:32 PM
I've successfully bent 3/8 soft copper to 90 deg bends, approx 1.5-2 inch radius bends, using a hand tool / small tube bender purchaced to do car brake lines.
The tool has a white plastic/nylon half circle "shoe" "die" with a few radiused / rounded grooves for a few sizes of small tube. Likely for 3/16, 1/4, 3/8 tube. The shoe/die grooves are shaped to prevent the tube from kinking as you do the bending operation. Two little rollers on each side of the shoe and a threaded "ram" drives the half circle shoe/die forward to do the bending.
You might find something like that at a very reasonable price at a Canadian Tire or Princess Auto store.
I built a 23 inch / bowtie in loop antenna, bending the bowtie part nicely with the bender, and butting and soldering the tube parts without fittings.
1/4 soft copper roll / tube should bend easier and with a smaller radius without kinking.
I also have purchased a roll of 3/16 soft copper roll / tube to eventually make GH receive zig-zag elements by bending.
If you can make or improvise some sort of a round die with the right size and shape groove in it - you might be able to successfully bend the quarter inch soft copper tube. (ex. carefully bend in the groove of a small pulley)
(gotta straighten a length of tube first, cut to approx length, then bend the angles you want, flatten and file the ends)
Key point - must use SOFT copper that comes in a roll - I think you've got that.
Hard copper tube / pipe is very difficult to bend properly without kinking.
(that I learned from of some of my internet "research" and reading)
Otherwise, the soft copper roll / tube is very easy to work with- straighten and bend - if you use the right method / right tool / or improvise the right tool.
I think you'll see some pictures of the tools etc. I used in my album or in the UHF loops thread.
(Ya, look in Mrvanwinkles photo album, second image, top left, run mouse pointer over image, you see image labelled "Tools 1" ... and in that image you'll see the little bender I used.)
2011-07-14, 04:08 PM
I have a Stealth Hawk up on my roof, but I'm getting way too many drop outs
By the way, regarding the choice of antenna you wish to build / to help get rid of the drop outs:
- GH antennas work really great. Give good gain and directionality esp. w/the reflector. Probably a very good choice. NA rods if you need VHF hi channel recepetion. (probably the ultimate). But you've got to be able to aim point the GH.
- SBL's - (14 inch dia SBL loop ?) SBL -shorted-bowtie-loops have been deemed very good loops for UHF only if you don't need huge gain. They're bi-directional / receive from two directions. (and they work real well, I understand, if built with 1/4 in copper tube. My (23 inch dia loop) 3/8 copper "bowtie-in-loop" works very well. Looking at your TV Fool, almost all channels are UHF and in one direction. Check out the UHF Loops thread. Lots of tips there for working with soft copper tube - experience I've gained building the 23 inch bowtie-in-loop.)
- The Bow-Tie arrays (McLapp 's ?) are given high regard.
See the first thread in this Antenna Research section:
"Best do it yourself OTA Antennas ..."
That thread points you to a few different KEY threads for the best different types of do it yourself antennas. GH's / Bowties / Loops and others. (Depending on what you're trying to receive and your TV Fool and your receive conditions).
2011-07-14, 05:34 PM
Yup, I have a roll of soft copper. Probably right, wire would be easier to straighten, and easier to bend sharply.
Eight gauge may only be half the diameter, but I doubt it would cost me enough gain to make it worthwhile to attempt making GH active elements from 1/4 inch soft copper tube.
Also, I may only have one VHF-Hi station, but it's a station that occasionally has some really good programming on it, so I'd like to be able to pull it in as well. Thankfully, all of the local stations share an antenna farm.
2011-07-14, 11:27 PM
I bought a 5 ft roll of 3/8" OD copper today at Lowes (made in Canada according to the box) to replace a kinked propane line. Oddly the 3/8" OD 5 ft roll at $ 5.38 was about 50% cheaper than the 1/4" 5 ft roll at $7.54.
I was surprised how much thinner the walls were than the old 3/8" OD it replaced. It made flaring and bending it much easier. Of course, you have to very careful handling it.
2011-07-15, 12:59 PM
I have a bunch of those green vinyl coated garden stakes that I'm considering using for reflectors for my GH build. Inside is steel tubing.
Is steel ok by itself or should I cover the tubing with aluminum tape?
This will just be a test antenna so I'm not concerned about rust right now.
2011-07-15, 10:33 PM
Yeah, I bought some of those too last year. :) Theyll be OK for reflectors. (using them for driven elements would be a nightmare, heh). The gain difference of them over copper or aluminum reflectors is pretty small.
2011-07-16, 12:16 AM
Or 6 gauge, if they have it.
I stopped by the local home depot to check their stock.
8 gauge for $0.64 / foot
6 gauge for $0.93 / foot
4 gauge for $1.47 / foot
The 4 gauge looks nice and fat, but it's expensive and doesn't look like it'd be easy to straighten, let alone bend.
2011-07-16, 08:29 AM
The gain difference of them over copper or aluminum reflectors is pretty small.
Great! That will save me some work getting this together. Thanks.
2011-07-18, 11:53 AM
MikeInMKE, Unclesam flattens the ends of the links, drills and tins then, then solders their corners together. The elements are then fastened to the antenna's framework using copper pop rivets and pre-curved copper backup washers. A process not for everyone, but for me it beats wrestling with a stiff wire then trying to figure out how to fasten it to the framework without compromising its electrical function. See my photo albums and 3 detailed projects on this subject at Instructables.com. Enter unclesam in the home page search box, then on the new page repeatedly click "NEXT" to page through them all. You will be presented with fewer ads and be able to use more functions if you create a free, no-risk login there.
2011-07-18, 03:41 PM
Assuming 1/4 OD soft copper tubing has an ID of 0.19 inches, and 6-gauge copper wire has an OD of 0.1620 inches, I wonder if I could use two-inch pieces of copper wire for the corners, and copper tube for the straight sections, with solder holding it all together. There might be enough slop in the connections to allow the pieces to lay flat in a tight jig during the soldering process.
Then the bends consist of two-inch long pieces of copper wire, which is easily clamped in a vice for bending, versus bending zig-zags into a five-foot length of wire.
The straight sections are all relatively short pieces (338mm for the top-hat mid section being the longest) of copper tubing, which makes the job of straightening it that much easier.
2011-07-19, 04:23 PM
I'm definitely not the most knowledgeable person here but I don't see why your idea wouldn't work electrically. I might be a little concerned about cleaning the inside of the 1/4" tubing properly to get a good solder joint. And I still think the solid wire is easier even if it takes a little longer to work it straight. :)