Best Metals for Antennas: Performance, Soldering, Welding, Bending, Working

[theMikeD]

1/4" diameter wire doesn't sound like something I'm going to find at home depot....I'll look though.

I just tried the drill trick to straighten wire on some old 14/3 I have laying around...worked aces, so that's a neat trick. 1/4" wire though...that's going to be some stiff stuff!

...Mike

[rvsixer]

Originally Posted by theMikeD

1/4" diameter wire doesn't sound like something I'm going to find at home depot....I'll look though.

They carry it, but iirc at about $3usd/ft. They also have 1/4" flexible copper tubing (refrigerator coil kit, 20' for about $0.80/ft). A spring type tubing bender and you are good to go.

I've used versatube for aircraft projects before, and leaning towards it for my build. Very easy and forgiving to work with, relatively inexpensive:
http://www.aircraftspruce.com/catalo...3versatube.php. They also sell the 6061 if you go that route.

[rick5127]

Mike,
Home depot has 6 cu gage wire and it will be fine for the driven element. Not sure it is strong enough for the reflectors though unless you build a lot of support into it. I built my reflectors out of 3/8 cu but I doubt it was worth the expense. Finding an old antenna or two around might get you some alum rods you could use cheap.

Oh and my build is listed in my signature. I went to some extremes as an exercise. Maybe in futility. lol

And I am still not done with it. I keep getting sidetracted.

[300ohm]

We have an industrial wreckers in town, I think I may swing by there tomorrow to see what I find. Maybe they have old antennas or scram aluminum.

Thats one of the best places to get materials for diy antennas.

[theMikeD]

I found some of this at the scrap dealer. It's 5/8" aluminum tubing. I'm thinking this might do the trick for the reflectors. It's $1/ft. Thoughts?

[nikiml]

you need about about 34 1/2 feet for the straight elements (for GH10n3). the tubing should do for that.

But it is probably not good for the bent elements.

Also - solid aluminum should be cheaper.

[theMikeD]

The solid rod was $6/lb, and the tube was $1/ft. I guess I'd have to run the math Maybe they'll give me a deal if I buy a crap load of it.

I also re-read a few posts and I see that the reflector rods can be as small as 1/4"...somehow in my head it was 1/2". Does the diameter matter for the reflectors? Or the bendy part for that matter?

The stuff rvsixer recommended looks like an easy solution to me having no tools to bend wire

[300ohm]

to me having no tools to bend wire

You don't have an old board and an old nail ???

$6 a pound for scrap aluminum is a lot, considering they only pay you about 65 cents a pound for it when you take some in.
http://www.metalprices.com/

[nikiml]

by my calculations 12 ft of 1/4" dia round solid aluminum would be aprox .7lb or ~ $4
which comes to ~33 cents per ft.
much cheaper.
and easier to bend...

[mrvanwinkles]

The wide tubes are a great idea and build idea to simplify the design of the whiskers.

Idea - a little more complex, more work, not sure if worth the effort - but here it is:

1. Cut the tubes lengthwise in half, for most of their length, and then bend them open / spread them open at the correct angle - and make it a true whisker that way.

2. Cut the tubes into quarters, for most of their length, and then bend them open / spread them open at the correct angle - to approximate a 4-pronged "CONE". [ Now you're getting into real 3-D cone approximation ]


Cutting tubes accurately and straight lengthwise is not easy.

( I did a steel one, 1 inch thin steel electrical conduit tube, for about an 8 inch length, cut it in half lengthwise with a reciprocating saw / sawsall, and the tube in a vise - but not easy. Needed some half pieces to attach and get welded onto something else )

But if the tubes are thinner and softer material - like AL or CU - and if you use the right guide and the right cutting tool / cutting machine - I think you could do it well - straight and easy.

ex. Metal bandsaw with a jig to guide the tube straight and centered as you slide it lengthwise to do the cut(s).

ex. Table saw with thin blade. Again, need a cutting guide.

Careful - could be a dangerous procedure unless the workpiece is held and guided properly - and unless you have the right blade and machine and feed and speed to cut the tube safely, properly and efficiently. Machinists will know all about this sort of stuff.


In another thread I wanted to experiment with real 3-D CONES or approximations - but I don't have alot of time - a million other projects and responsibilities at the moment.

... and ... some mentioned that they think it would not lead to that much improvement.

Some mentioned, if you make 3-D cone approximations - you can make your whiskers shorter, and have the same performance - thereby saving space and material.

I imagined a multi-pronged whisker - which is what cutting the tube in four and spreading it would be.

Anyway - just an idea.

Good work with the 1" AL tubes.

[HDTV Junkee]

FYI -- Aluminum Tubing is usually very readily available. Old Tent Posts as an example. Tomato steaks (green plastic coating).

Just a couple of weeks ago, we had our shingles replaced up in the attic (after 15 years), as well as the big heavy metal air vents in favour of the newer plastic models.

So just for kicks, I cut up two old aluminum red "mop" handles (into 4 - 21 inch pieces -- mounted on wood board (one and one-half inch spread) -- with baluns on each and fed into a splitter (in reverse).

I don't have to worry about the bowties hitting the roof and now I can get another 3 feet height (for my one TV).

Receive all T.O. and Buffalo stations. Fox 29 (in Mississauga is usually pretty tough for me), but not now -- up to 60 to 80 percent depending on tropo affect. 13-1 and 28.1 are iffy because of the angles and the reflectors that I use to point toward Buffalo.

Of course 9 and 11 are solid as anything -- maybe too strong for the tuner sometimes (98%).

These "mop" handles for anyone that wishes to have one are the common "red" ones available at most retail and dollar store outlets.

Sometimes, Freshco / Sobeys sells ones for a couple of dollars, where the blue mop-head has been torn off and is of no use to anyone.

[mrvanwinkles]

Aluminum Shower Curtain Rods, purchaced at many hardware stores, are maybe around 5 or 6 feet long - if I remember correctly.

[ I can check - might be going to the hardware store later today for other stuff ]

They're definitely around one inch in diameter.

They're nice THIN aluminum material - probably very easy to work with.

5 ft = 60 inches, gives 8 tubes of only 7.5 inches

6 ft = 72 inches, gives 8 tubes of 9 inches

[ not counting any length lost for the cuts ]

[ but if you cut them with a tube cutter, you probably don't lose much length ]

so ... if you can get a 6 ft long AL Shower curtain rod - might be a good piece of material to use - for the do it yourselfer to build the TUBE elements.

Happy Building ! And Modelling !

[nezdepain]

This thread http://www.digitalhome.ca/forum/show...44#post1419444 touched briefly on the topic of metal and yagis. My assumption is that except for the driven element (the dipole), the metal used would not matter much since the elements are not meant to be connected together (non-metallic boom), so conductivity is not a factor. Is the assumption right? Would there be a performance improvement if all elements are made of copper versus stainless steel?

[stampeder]

nezdepain, always stay with the same metal for elements, directors, reflectors, and attachments and you will have great results if the antenna design is good in the first place. If you use the Search This Thread tool for "Galvanic Corrosion" you will see great info on why mixing of metals should be avoided. For the best performance per cost most people are going with all aluminum construction these days. A non-conductive boom would mean using plastic or wood, but those are too weak to last long so metal should be used.

[nezdepain]

Thanks for the answer. The antenna is already built and is the attic. There is no issue of contact between two sorts of metal in this case. The driven element is made of copper and the parasitic elements are made of steal. I am just wondering "what if" all elements (parasitic and D.E) were of copper? In theory and practice, would it change anything on performance alone?