homebrew 6m beam safe element diameter

[mr_fx]

I am getting ready to build a 6 element 6m beam...

I already have an aluminium 20 foot boom

I plan to use 1/2" solid for the driven element...

What would be the minimum diameter for the directors and reflector?

I understand from an electrical standpoint anything will work... my question is more from a mechanical standpoint

Thanks in advance

 

[KC9Q]

Hi MR_FX,

I'd used 3/8" tubing for all elements. Nothing wrong with the 1/2" solid rod, however, the solid rod just adds a lot of needless weight, plus the solid rod is needless as the RF conducts on the outer skin of the rod.

Mike

 

[mr_fx]

Well because 3/8 solid aluminium is only $7.80 for 10ft but tubing is like $50 for 10ft

 

[Road Squawker]

Well because 3/8 solid aluminium is only $7.80 for 10ft but tubing is like $50 for 10ft

unused TV antennas are pretty cheap

 

[Captain Kilowatt]

Well because 3/8 solid aluminium is only $7.80 for 10ft but tubing is like $50 for 10ft

$50 for 10 feet of 3/8 tubing???? Better take another look at those prices. Something is DRASTICALLY wrong. That sounds more like boom material and a heavy one at that and not element material. Texas Towers has 3/8 tubing for $7.80 for a 12 foot length which is typical.

Texas Towers, Aluminum Tubing Page [12' Lengths]

There is no way I would use solid rod for elements that size.Far too much weight. My six element 6m yagi was build from the remains of an old Wilson Shooting Star 11m antenna. It has six foot center sections of 5/8 tubing with the ends made from 1/2 inch tubing which makes it real heavy duty for 6m.

 

[mr_fx]

Metal by the Foot, Inc.

They are local

Maybe i am looking at it wrong?

 

[Shockwave]

Metal by the Foot, Inc.

They are local

Maybe i am looking at it wrong?

I've purchased a lot of aluminum over the years and I've never in my life seen such inflated prices. Not like 50 or 100% too high but more like 485% over priced. I speced a piece of 7/8 tubing at 6 feet from DX engineering at $7.49. The same piece from metal by the foot is $34.02.

They are obviously trying their best to take advantage of people that don't know market value. Then they have the nerve to say their prices are adjusted to compensate for fluctuating metal value. You never have to readjust your price based on the metal cost when the product is already priced this many times too high.

PS: They must take solid rod and drill the center out for their tubing to cost this much. Perhaps someone should send this company a few links to competitors so they can see how ridiculously they have priced themselves out of the market.

 

[Captain Kilowatt]

Metal by the Foot, Inc.

They are local

Maybe i am looking at it wrong?

Nope. You are not looking at it wrong just looking at the wrong place. Holy mother of God what are they thinking? The company partner's must be named Dewey, Screwum, and Howe.

 

[wavrider]

1/2" or 3/4" EMT conduit get it at any home supply store for a few $ per 10'.

Works great.

Put a gamma match on that 6 meter yagi and have fun.

 

[Captain Kilowatt]

EMT is pretty heavy and will rust eventually. As for the feedpoint a Beta match with a split driver element and standard half wave coaxial balun works great. No fooling around with gamma tubes and everything is balanced and DC grounded. I'll try and post pictures and a dimensional layout of mine in a day or so. At work on my phone right now and cannot post the images on my laptop. It is optimized for maximum forward gain and has. Six elements on a 16-17 foot boom. Seems short at first until you see the ref-driver-#1 director spacing. The first director is only about 16 inches in front if the driven element. This supposedly increases the coupling. I believe it. Last week I assembled it for installation on the new tower and measured the impedance each time I added an element. The ref did little but the first director did a LOT. The F/B on it is fantastic but the bandwidth is a bit narrow. I don't mind as I only ever use the bottom 1MHz anyway.

 

[wavrider]

Search Results for emt conduit at The Home Depot

Hard to find aluminum tubing for that price.

If coated with any type of environmental coating ( paint) it will last for years.


Gamma gives a broad band of coverage, all of 6 meters is possible when I built my four element it covered the whole 6 meter band, of course it is not optimized for the lower 1mhz just a plain simple four element yagi with .2 wl spacing between the elements.

 

[BJ radionut]

This is my 6m beam...I decided to purchase mine this time rather than build, price R&L game me was to good to pass up!
All the Plans to build this are on the Innovate antenna website, which is a cool deal! I just wish now I would have gone the 7 element version on the 20 ft. boom...Maybe when the 60 ft tower goes with the Hazer!
All the Best
Gary

5 element 50MHz LFA-VR Yagi (4.35m)

 

[Captain Kilowatt]

These are the dimensions of my 6m yagi. The dimensions on the left are element spacing while the dimensions on the right are the tip to tip element lengths. The driver element is actually slightly shorter than the first director because of the use of the Beta match aka hairpin match.

Feedpoint without balun.

Half wave coaxial Balun attached.Coax to rig attaches to the middle SO239 jack.

Mounted on my old tower between the 2m yagi and a broken A3 tribander.