10 and 6mtr monobanders

[Glenn NY4NC]

I'm looking into the future for my new QTH. I'd like to install 10 and 6 meter monobanders on a tower. Either Hygain or cushcraft used to have 4 and 5 element monobanders with a decent boom length for 10 meters but all I see now are three element wimpy beams on short booms. Yea, I know I could build it myself but I'd rather buy the box with all the parts and just assemble...

Who makes a decent 4 or 5 element 10 meter monobander?

This looks like a good choice for a 6 meter beam... (9 elements on a 40ft boom)

http://www.texastowers.com/6m2wlc.htm

[WA1GFZ]

TOM Vu engineering

[Pete, WA2CWA]

I've been using this one for the last three years. Half the windload and weight of the one you posted and only 1db difference but beamwidth a little greater.

http://www.texastowers.com/6m7jhv.htm

M2 also makes some nice monoband beams
See: http://www.m2inc.com/index2.html
Click on Products and then Monoband.

[K1JJ]

Yep, M2 makes decent antennas. There are some things I don't like on some of them, like their mechanical feeding systems that fatigue and break, but over all, they are better built than most.  Telrex is even better if you can afford them.

The M2 5el 6M Yagi is very popular on an 18' boom. Also look at their 4el? or is it 5el? 10M Yagi.

These two beams are good choices if you intend to stack them later on. Otherwise for a single Yagi, go with the longest boom Yagi you can handle and expect the cleanest horizontal pattern.

BTW, do consider downloading a Yagi modeling program and building them. You can save 75% and build a stronger beam by far.  Order your SS u-bolts from McMaster Carr and visit the local metal scrap yard for the alum..

T

[Glenn NY4NC]

Hi Tom;

That's exactly what I want to do, stack them,  the 6m above the 10m, so those two models would be a good choice for that application? Is that because the longer the boom length, the more vertical distance you need to have between the two ants?

The M2 5el 6M Yagi is very popular on an 18' boom. Also look at their 4el? or is it 5el? 10M Yagi.

These two beams are good choices if you intend to stack them later on. T

[WA1GFZ]

I was in a starr hardware a few weeks ago and they sold a number of tubing sizes from 1 inch to 1/4 inch rod. They even sell 1 inch square tube.
Small beams with short elements are easy to build.

[K1JJ]

Hi Tom;
That's exactly what I want to do, stack them,  the 6m above the 10m, so those two models would be a good choice for that application? Is that because the longer the boom length, the more vertical distance you need to have between the two ants?

Hi Glenn,

Well, what I meant by "stacking them" was to have two per band, like 5 over 5 for 6M. You can use shorter boom Yagis for this kind of stacking cuz you get the benefit of a narrower vertical pattern without a single long boom. Plus mechanical ease and a broader horiz pattern for less rotator use.  Stacking a pair also lets you switch 180/0 degree phasing for the very high angles that are common on 10/6M E-skip.

ie, I wud try to do a small pair over a small pair... even if they are 10/6M 3el Yagis and one set was fixed in a certain direction down the tower, like west for USA, etc.

But, if you want single Yagis, go the longest booms possible and  then for spacing you will want to get the two separate bands spaced at LEAST 1/2 wavelength apart for the highest band, if you can. That would be maybe 10' minimum for the 6M Yagi. The 10M Yagi will not see the 6M elements, and the boom is at right angles... so OK. They can be closer, but the patterns will start to degrade somewhat.  I know guys put them 4' apart, etc, but try not to if ya can.  With a strong mast, you can probably put the 6M Yagi at 15' above the 10M Yagi that sits on the tower top.

T

[Pete, WA2CWA]

Here's my current stack, bottom 5 element tri-bander on 26 ft boom, next 7 element M2 6M beam on 31 ft boom, top 17 element 2M beam on 31 ft boom. Got a 432 24 element beam on 18(?) ft boom to go above the 2M beam. I see little to no reaction between any of these beams but I don't analyze the heck out of them either.

[K1JJ]

Vely, bery nice looking install, Pete!

Crank up tower -  you're all set for old buzzard-dom when the bones ache too much to climb in 20 years....

With that 7el  6M Yagi at 70'? as I think you said, no wonder you were head and shoulders above the average NJ station last week on 6M up here.

Right now I'm racing to get up some ants before the snow. Don't think I will make it on some. The WX must remain perfect.  Today I'm welding up the side tower swing gates for  FOUR, HB  5el 10M Yagis to go at 30', 60', 90' and 120'. Just added a section of Rohn 45 Tuesday to get that tower higher for this job. This is the "free" tower that is now gonna be doing involuntary servitude as a dedicated 10M slave.  The Yagis will be rotated by ropes and tied off in a selected direction, depending upon propagation - the Armstrong method.  ie, If I'm working USA and Saki breaks in to tell me to listen to him in Japan, I gotta go out in the snow and do some serious yanking.  I hate rotators, but maybe someday might add them to this array, who knows?

T

[WA1GFZ]

Tom
It would be a Gotham Vertical pisser if you ran ropes into the shack and hook them to Yaz like in the grinch who stold Christmas.

[Pete, WA2CWA]

Good luck with all the tower work. I still have much to do here too but developed some nasty pain in the left knee for ladder and roof climbing. Some "Jack" makes the pain more tolerable but not for ladder and roof climbing. In these pictures, the tower height is only about 50 ft, which puts at the 6 meter beam at about 57 ft and the 2 meter beam at 64 ft. The tower extends to 75 feet. There's over 6 yards of concrete at the base.

[Glenn NY4NC]

Hi Tom;

A few more questions..(Assuming a rotor install) You said... "the boom is at right angles"... Do you mean one should point West while the other is pointing north? 

Yes, we're talking about rotor mounted, 10m yagi on the bottom, 6 meter yagi on top. So 10ft spacing will be ok?... that's good. I might as well go for longer boom yagi's to get more gain. So it doesn't matter if the 6meter yagi on top has a longer boom than the bottom 10m yagi? the 10m yagi won't see the long boom 6m yagi? no interefence problems there?

Thanks...(it will be cool to work Sushi on 6 when the band opens in a few years)

Hi Glenn,

<snip> if you want single Yagis, go the longest booms possible and then for spacing you will want to get the two separate bands spaced at LEAST 1/2 wavelength apart for the highest band, if you can. That would be maybe 10' minimum for the 6M Yagi. The 10M Yagi will not see the 6M elements, and the boom is at right angles... so OK. They can be closer, but the patterns will start to degrade somewhat.  I know guys put them 4' apart, etc, but try not to if ya can.  With a strong mast, you can probably put the 6M Yagi at 15' above the 10M Yagi that sits on the tower top.

T

[Glenn NY4NC]

Hey Pete,

How ya gonna get that 432 beam up there on top? Does the tower tilt over?

[K1JJ]

Hi Tom;

A few more questions..(Assuming a rotor install) You said... "the boom is at right angles"... Do you mean one should point West while the other is pointing north? 
So it doesn't matter if the 6meter yagi on top has a longer boom than the bottom 10m yagi? the 10m yagi won't see the long boom 6m yagi? no interefence problems there?

Hola Glenn,

The booms both point in the same direction. The 6M els are too short to be seen by the 10M beam, but the 6M beam's boom is long enuff to have an effect on the 10M. But it will be at right angles to the 10M els, just like the 10M boom, so no problem.

However, the 6M beam will be affected by the 10M els, so that's why you need the spacing. BTW, yes, the longer the boom, the larger the "area of influence" in three dimensions. So, a short 3el el Yagi can be closer to other antennas than say, a bigger 6el Yagi.   The booms can be ANY length, since they are both at right angles to the els on both Yagis.

In your case, I would try for a minimum 18'-24' / 5- 7el  Yagi on 6M, and a 5el/24' boom for 10M. Or LONGER, why not? I wud make the spacing 15' using two 10' masts coupled together with an outside sleeve, or get a 20' mast. Use 5' into the tower for the rotator/thrust bearings and let 15' hang out for the 6M at the top and for the 10M at the top plate.

You will have interaction that amounts to less than 0.1 db for forward gain on the 6M and the f-b will be almost free space.  Closer than 15' apart and the pattern starts to change slightly at 10'  -  and at 5' gets seriously ugly like a $4 ho or 5 day old shushi dinner in the frig. Shoot for 15' and you can sleep like a turd.

T 

[Pete, WA2CWA]

Hey Pete,

How ya gonna get that 432 beam up there on top? Does the tower tilt over?

Yep. It's an Ez-Way RBZ-75 crank up/tilt over tower. Leg to leg length on the base section of each side is 18 or 19 inches. Tower is free-standing and capable of 25 to 30 sq. ft of antenna wind load. There is a 10 ft high steel pole about 7 to 8 in in diameter held in place by 2, 1 in dia. cement anchors in the cement. There is a hinge plate welded to the top of the pole and another hinge plate welded to the tower. Large steel pin holds them together. There is a winch on the pole. Cable from this winch swings around a pulley at the bottom of the tower and then swings back to the pole. There is a large steel pin that is inserted through a set of brackets at the bottom of the pole and through the tower, to keep the tower plum in the upright position. To tilt over, with the tower fully nested, I pull the bottom pin, let out a foot or so of cable to pull the tower off plum, and gravity and the winch tilt the tower over. There are also two steel pipes attached to the pole that act as additional legs to keep the pole rigid and provide balance for the downward forces. These two legs are also held in place in the concrete with 1 in cement anchors.

I could find one photo in my photo file that shows the base section.

[Glenn NY4NC]

Thanks for the advise Tom. That's exactly what I'll do. (20ft aluminum mast with 5 ft in tower)

Think I'll go with the M2 model 6M7 (7 elements on a 26' 9" boom) on top for 6m and the M2 model 10M4DX (4 elements on a 24ft boom) for 10m.

It's going to be either a 60 or 70ft aluminum tower so I want to keep the antenna weight and wind loading down. I'm one of these folks that are alergic to tower climbing so I'm thinking about using the "Hazer" system. Steel crank up towers are way too expensive!

In your case, I would try for a minimum 18'-24' / 5- 7el  Yagi on 6M, and a 5el/24' boom for 10M. Or LONGER, why not? I wud make the spacing 15' using two 10' masts coupled together with an outside sleeve, or get a 20' mast. Use 5' into the tower for the rotator/thrust bearings and let 15' hang out for the 6M at the top and for the 10M at the top plate.

You will have interaction that amounts to less than 0.1 db for forward gain on the 6M and the f-b will be almost free space.  Closer than 15' apart and the pattern starts to change slightly at 10'  -  and at 5' gets seriously ugly like a $4 ho or 5 day old shushi dinner in the frig. Shoot for 15' and you can sleep like a turd.

T 

[Glenn NY4NC]

I just checked the price of the 4 element M2 10 meter beam at $531 Geez!!!  maybe I will build from scratch after all!!!....

[W2VW]

Other than the element spacing which is not maximized for forward gain, these aren't too bad for the money. Scale it down & go. I know a guy who has had one of these up for the last 5 years without too much trouble.

[Glenn NY4NC]

I believe it is maximized for forward gain. I don't think yer gonna get more than 8DBd out of four elements on a 24ft boom.....

Other than the element spacing which is not maximized for forward gain, these aren't too bad for the money. Scale it down & go. I know a guy who has had one of these up for the last 5 years without too much trouble.

[K1JJ]

I just checked the price of the 4 element M2 10 meter beam at $531 Geez!!!  maybe I will build from scratch after all!!!....

Sounds like a plan, man.

Yeah, the commercial prices are outrageous. Do consider building all of your beams. It will open up a brand new facet of the hobby for you. I've encouraged many guys to build them and so far all have been successful and seem even more excited about their project than building a rig.  It interesting to see the reactions you get on the air when you mention that your Yagi is homebrew. Anothet topic of conversation when you run into other guys that build them too. Later, you will find it a natural to build up a 20M beam cheap-cheap.

Call around and try to find a scrap yard that sells alum for $1.50/ pound or less.  At that rate I was able to build FOUR, 5 element [24' boom]   10M Yagis here last week for about $200, including hardware. The booms are so strong they will not even need overhead trussing, but I'll add it anyway. Bullet proof to 1/2" radial ice and 120mph according to YagiStress mech modeling.

A Hazer seems like a neat idea, but the load seems limited, as you know. No 40M Yagis or big 20M 6el beams wid that.

You have lots of time to plan - you might even build the Yagis up slowly over the Winter.

73,
T

[Glenn NY4NC]

Tom, do you also make your own boom to element clamps?

[K1JJ]

Tom, do you also make your own boom to element clamps?

Do you mean boom to elements mounting plates?  For the plates I usually get a 1/4" or 3/16" thick sheet of aluminum and  saw off  4" X 6" plates. Two u-bolts hold the element and two u-bolts go at right angles and hold the plate to the boom.  I also use a 1/4" nut and bolt to "pin" the plate to the boom so that the ele does not spin in a hurricane.  [they may spin with only u-bolts depending upon the el length, so I do it on ALL Yagis]

The plate clamps are stainless steel u-bolts that I get from McMaster-Carr.

ALL eles are u-bolted directly to the plates, no insulation. The driven el uses a T match and a 1/2 wave coaxial balun.  Simple and works FB on all bands. M2 uses the T match and coaxial balun for most of their Yagis also. They also use a hairpin,  but I prefer the T-match these days. 

T

 

[Glenn NY4NC]

Sounds good master Vu  .... What would you suggest for element diameter?

I guess It's time for me to get that ant software eh?

[K1JJ]

Sounds good master Vu  .... What would you suggest for element diameter?
I guess It's time for me to get that ant software eh?

Use whatever you can find cheap.  I usually use 5/8" diameter elements for 6M. They can be run without tapered tips - strong.  For 10M I usually use a  5/8" el tube to a 1/2"  tube taper.

On all els, no matter what diameter, I use an outer sleeve over the center on the plate for strength. The sleeve is 6" long and is the same length as the el plate. The u bolts cannot crush this double thickness combo.
So, if the el is 5/8" dia, then you slide a 3/4" dia, 6" long sleeve over the center.

Yes, download the software and start playing around.

T

[W2VW]

Other than the element spacing which is not maximized for forward gain, these aren't too bad for the money. Scale it down & go. I know a guy who has had one of these up for the last 5 years without too much trouble.

Sorry, the link was missing.

http://www.copper.com/cgi-bin/checkitout/checkitout.cgi?catalogSTORE:CKIE:prodM00-05108+