Another material I have a small stash of and may get applied to a project is storm window/window screen framing channel, just wondering how that would do, it's aluminum, I think it's fairly malleable, but its a bit of a odd shape, some of it's U section some H... ish.... reflectors???

The U or the box shape would work great for a portable GH. :p The H shape would be fine for reflectors, having the flat side towards the transmitter. Aluminum is a great material for antennas, just use aluminum or zinc plated hardware with it.

I like that line, "Just to get some metal in the air"....

I believe you may have been misled somewhere. According to the Copper Development Association (copper.org) and the Canadian Copper and Brass Development Association (coppercanada.ca), copper plumbing tube is essentially 99% pure copper or better, in order to meet the standards laid out by ASTM B88 (American Society for Testing and Materials).

Hi folks,

Also I don't know how many are aware of this but plumbing pipe "copper" is not "copper" it's a variety of brass with about 15% zinc in it.

I believe you may have been misled somewhere. ....

Dang, yes, I believe I have. Sorry all. An engineer talked me out of using plumbing sourced copper for something a couple of years back telling me that for a fact. Funny thing was, I think I found something on the net that appeared to confirm it back then too. Odd.

A possible source of this confusion I see now is that plumbing fittings are often made from "red brass" one version of which is 85/15 and also that red brass may be more popular in other countries as a replacement for copper piping.

Red brass drain pipe was fairly popular in cities about 75 years ago, but rarely used for the past 40 years, except for tub drains until the PVC junction. PVC and CPVC are the cost effective copper replacements. Im not crazy about the PEX tubing which is also used.

Maybe somebody could point me to alluminium wire which I used to buy at Radio Shack. I believe it was 300 OHM allum. approximately 4 mil.
It seems to have disappeared, The Source doesn't carry it and I haven't as yet seen any staff there who can direct me to it....any ideas??

Cheers, Stubblies

Maybe somebody could point me to alluminium wire which I used to buy at Radio Shack. I believe it was 300 OHM allum. approximately 4 mil.
Heh, nope it wasnt 300 ohm wire, it was 8 or 9 gauge aluminum ground wire. Looking at the old Radio Shack catalogs, it was 99 cents for 40 feet just 20 years ago. I used that stuff in the first GH I built, but alas, have no more of it.

I think it was discontinued because of code violations. Most ground rods, the ones you pound into the earth, are copper clad. Aluminum and copper will eventually form corrosion, making a bad connection. Also eventually, there would have been corrosion between the aluminum and the brass (or brass plating) that was used on the lightning arrestors they sold for use with 300 ohm twin lead.

I've got some stainless steel banding left over from the chimney mount straps. The coil can be flattened straight with a hammer.
Roughly about 3 1/2 meters leftover. Was thinkin may be used for Yagi directors or sumthin, what ya think?

Stainless steel is about the worst conductor.

Wire conductivity

Below a wire conductivity table to be used for LD card type 5, wire loading

Material Conductivity
S/m
Perfect 9.9e99 (lossless)
Silver 6.29e7
Copper 5.80e7
Pure Alumin. 3.77e7
Al. 6063-T832 3.08e7
Al. 6061-T6 2.49e7
Brass 1.56e7
Phospor bronze 9.09e6
Stnlss Stl 302 1.39e6

It may be OK for directors or reflectors, but why bother with the thin strapping ? I think it may require more effort than its worth.
Stainless steel is a hard material to work with. Its tough to cut, drill or bend, cant be soldered, and is relatively heavy.

why bother
No reason, just didn't feel like tossing it in the trash is all.

The strapping is great for other uses, like holding up water pipes, etc, once you get a starter hole punched in it. :p

I have some difficulties to find #6 solid bare wire or 3/16” copper rod. Can I utilize for the driven elements a 1/4” copper rod?

http://www.user.dccnet.com/jonleblanc/Canada_TV_Stations/Gray-Hoverman/DBGH_VHF_hi_Antenna.pdf

Jean-Marc

Sure, its just harder to bend and is heavier. The gain difference will be minimal. 1/4" is almost 2 gauge.

Cheaper yet for you in Quebec would be aluminum rod from Metal Supermarket.

Thanks for the information.

Jean-Marc

Just get the type of aluminum that bends without breaking. You may have to test a piece before buying, as sometimes stuff is mis-marked. :p

I read the Skin effect (http://en.wikipedia.org/wiki/Skin_effect) article on wikipedia today and I'm starting to wonder if 1" aluminium tape isn't actually the best element material for an inside or attic antenna like the SBGH or the Stealth Hawk, like the one Bob_K showed in post #26 of this thread (http://www.digitalhome.ca/forum/showthread.php?t=109042&page=2).

As I understand it, current will only flow in the first ~25 microns (that's 0.025 mm) of the conductor anyways. Might as well have a flat element that's perpendicular to the EM wave in order to maximize signal reception instead of wasting metal that's not used to carry current anyways.

What do you guys think?

It'll work as long as the tape is conductive and you fold it right to maintain the conductivity.

I'm thinking that for indoor antennas, 1" aluminium tape might even be more efficient than #6 awg wire as it would have a bigger cross-section to "gather" signal from the air. It would also be easier to work with. Obviously, for outside antennas, other considerations like material strength and wind resistance come into play, but then it might be better to use copper tubing than solid wire as what we are looking for is to increase the amount of surface exposed to the signal instead of trying to increase overall conductivity.

I recently saw a common source for copper foil tape, available in different widths, on a tv craft show about stained glass hobby. I wasn't sure if this source had been previously included in this thread, thought I would mention it. The copper tape is wrapped around all the perimeter edges of each piece of glass. A soldering iron and solder are then used to connect the glass pieces where their edges butt together. This kind of tape would seem to be a good material for making antenna elements and reflectors of the thin metal strip variety, especially those that will be used indoors. Corners could be soldered or connected using copper pop rivets (sold online by gutter industry suppliers). Reflectors for outdoor use could be made by sticking narrow strips of copper foil tape to the INSIDE of half-inch plastic pipes. These reflector pipes could be completely sealed with caps, so weather would not pose a problem to the tape adhesive. The resultant antenna would be heavier and have more wind resistance than those made instead with small diameter metal tubes, but copper tape strips inside plastic pipes might offer an alternative method of construction where those considerations are not an issue.

So to sum things up would you say to make a nice GH antenna the best material would be between 1/8" and 1/4" copper or aluminum pipe or rod? Is there an advantage using solid rod as opposed to a tube? I might be able to get really cheap 1/8" stainless rod, steel doesn't seem to be that great though hey?