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Author Topic: Hex beam questions  (Read 2334 times)
KD2CJJ
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Posts: 368




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« on: December 01, 2012, 07:29:43 AM »

Hi

I'm finally getting close on which antenna I was going to finally end up with.  Right now I am running a fan dipole at 30 feet.  I'm not overly happy for 1 I can't rotate it and 2 it's compromised in that one leg of the dipole is not perfect and draped over the top of a tree.

I was considering a ma5b or hex beam.  And from my research the hex is the way to go if the xyl will allow... I figure its better to ask for forgiveness than permission.

With that said, how does one get the antenna up a ladder extended 25 feet to the second story of a house.  Right now I have a steel mast attached to the sideof my house from the ground up 30 feet using side brackets reinforced from the attic... It lasted through sper storm sandy so it passed the strength test.  So what's the best method on greeting the antenna up? And 2 once up ow do I attach it to a 8 or 10 foot mast safely.   Would like your guidance and experience.  Any other comments outside the specific question welcome.

Thanks
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73

Mike
KD2CJJ
K2DC
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« Reply #1 on: December 01, 2012, 08:20:00 AM »

Just a suggestion - you might consider dropping the steel mast so you can attach the rotor and antenna at/near ground level.  Then you can haul the whole thing up from the roof level.  Seems to me that it would be a lot safer than trying to get it mounted from 8' or so above the roof.

73,

Don, K2DC
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WX7G
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Posts: 5917




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« Reply #2 on: December 01, 2012, 09:12:59 AM »

I really don't like working on the edge of a roof. I would reduce the mast height such that the antenna mounts 4' above the roof.

The antenna can be assembled on the roof or pulled up assembled by a rope.
« Last Edit: December 01, 2012, 09:17:07 AM by WX7G » Logged
KA5N
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Posts: 4380




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« Reply #3 on: December 01, 2012, 09:41:52 AM »

While an assembled hex beam is not very heavy, it is akward to handle and you probably
should have at least one helper.  If you use a ramp  (2X4s') you can just pull the Hex
up.  At a two story level you need at least two people to sit the beam in place.  If you
have a flat roof it is much easier.  I wouldn't consider an unguyed installation unless
you want the hex back on the ground.  Even though the wind loading is slight, the
typical mast type installation will not stand winds without any guying.  Have you
considered a rooftop tower or a Rohn tower bracketed to the siding?   However you do
it the rotor will be better if placed at the botton so you can lift out the mast and
replace or repair the rotor.  
Good Luck  by the way Hexes are the cheap easy way that do indeed work well.

Allen   KA5N
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KD2CJJ
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Posts: 368




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« Reply #4 on: December 02, 2012, 08:50:50 AM »

The main mast is a steel mast and is fairly heavy.. It's three 10 foot sections coupled into one another so it would be too heavy overall to mount the rotor at the bottom. I was planning to mount the rotor on the top.  It would be only 4 feet from the bracket.  From there I would put on a 8 foot section to get me above 33 feet.   I have considered a tripod on the roof but I need a new roof and don't want to touch it till its done and the side mount mast is there..  It's not going anywhere...it lasted through sandy...  I have  60 foot oaks that came down and the mast held... My dipole unfortunately did not.  I have a wire up for now to hold me through the winter.

Sounds like there is no one way...

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73

Mike
KD2CJJ
VE3FMC
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« Reply #5 on: December 02, 2012, 10:23:48 AM »

The main mast is a steel mast and is fairly heavy.. It's three 10 foot sections coupled into one another so it would be too heavy overall to mount the rotor at the bottom. I was planning to mount the rotor on the top.  It would be only 4 feet from the bracket.  From there I would put on a 8 foot section to get me above 33 feet.   I have considered a tripod on the roof but I need a new roof and don't want to touch it till its done and the side mount mast is there..  It's not going anywhere...it lasted through sandy...  I have  60 foot oaks that came down and the mast held... My dipole unfortunately did not.  I have a wire up for now to hold me through the winter.

Sounds like there is no one way...



Mike if I understand your setup correctly you have 25 feet to the peak of the house. So if the mast extends up past the peak by 2 feet you could mount a rotor on that. Any rotor that is center mounted would work. Then you could mount the Hex Beam on a piece of mast, about 5 feet would be the maximum I would use.

Get it on the roof, and two of you just lift the beam and the mast up and drop it into the rotor. With 2 feet of mast above the peak that would mean you only have to lift the mast/beam up 3 feet above the roof line.

So 27 feet of mast from the ground up to the rotor. A foot or so for the rotor gives you 28 feet, then 5 feet of mast from the rotor to the bottom of the hex beam gives you 33 feet.

You could go higher if you could guy the mast. However that would require you to lower the existing mast down, mount the rotor and beam then lift the mast/rotor/beam back up to attach it to the house. Lot of extra heavy lifting to gain a few more feet IMO.
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WB6BYU
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« Reply #6 on: December 02, 2012, 11:47:19 AM »

There are always several ways to do something, but you have to determine
what will work (and is safe) in your specific instance.

For example, if you have room beside the house you could tilt the existing mast
down, add the rotator and antenna, and then tilt it back up into position using
a come-along or winch.  Depending on the size of the mast, you could add
steps and climb it up to a point where it is convenient to work on it.

Hex beams tend to be light compared to some other beam antennas.  One
person can lift it, though it may bet awkward in the wind.  I typically
get up on a tower and attach a pulley and rope, then let the folks on the
ground pull the antenna up to me.  If necessary you can run a tram
line out into the back yard and clip the antenna onto that so it rides
up the line to the top of the tower.  (Things can get awkward at the top
of the tower unless thought is given in advance to which pieces go where
and how to get the mounting bracket around the mast.)  You can also run
a pair of ropes for the antenna to slide on as it is pulled up.  Depending on
the design you may be able to fold up the spreaders like an umbrella and
carry the antenna up to the roof, then fold it back out.

Actually, renting a bucket truck to lift it into position might not be a bad
idea, either.

Generally you want to inspect your antenna regularly, so developing some
scheme that makes it easy to access the antenna at the start will make
things easier over the life of the antenna.
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K4RVN
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Posts: 758




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« Reply #7 on: December 02, 2012, 01:19:51 PM »

Hello Mike,
I own a K4KIO Hex Beam 5 band. It weighs about 26 pounds plus the rotator which can be a lightweight TV type.
My advice is to spend about 150 bucks for a 40 ft or so fiberglass light duty push up mast and make or buy a tilt base. Tie a small pulley to your existing mast using your ladder up above the roof level and use a small rope to tilt the completed antenna and rotator
up to the existing mast. Strap it to the existing mast for support and you are done.
Don't try to work off a high ladder or at the edge of the roof as one mistake could ruin you for life or even end it all for you.
A scrap piece of 3/4" pipe just driven into the ground 3 or 4 ft makes a good pivot tilt over base. You can figure out the mechanics
of attaching the push up mast after you get it for drilling holes, etc. The antenna is awkward as someone posted, but not too heavy
for two people to handle with ease.
What ever you do be safe and take no chances. Her is a link to a pust up mast with deatails of what some have done. Scroll down.
http://www.mgs4u.com/fiberglass-push-up-mast-additional.htm

Frank











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NN4ZZ
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Posts: 36




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« Reply #8 on: December 03, 2012, 03:47:13 AM »


as Frank said "Don't try to work off a high ladder or at the edge of the roof as one mistake could ruin you for life or even end it all for you."

If you end up with a tiltover tower or mast you might want to look at the HexLock.  Then you can avoid ladders completely.   

http://www.nn4zz.com/HexLock.html

Regards, Al / NN4ZZ

Caveat: HexLock is one of the safety and convenience products I offer for tiltover towers











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K2MK
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Posts: 389




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« Reply #9 on: December 03, 2012, 04:09:38 AM »

Folks have suggested tilting up a mast. You have to be careful about how you hinge the base. It needs to be robust or the mast will sway sideways as you winch it up from the roof. Penninger offers robust aluminum masts and hinged bases. They are expensive but the overall weight will be less than steel which will make raising and lowering easier.

73,
Mike K2MK
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WX7G
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Posts: 5917




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« Reply #10 on: December 03, 2012, 04:54:03 AM »

The mast bracketed to the house is fine and I have used such masts. The way to keep it from falling down, and to make antenna installation safer, is to not get greedy and mount the antenna too far above the roof. Four feet above the roof makes the antenna simple to set onto the rotator.
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KD2CJJ
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Posts: 368




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« Reply #11 on: December 03, 2012, 12:40:49 PM »

Yea... this is kind of what I was suspecting..... My goal is to put the rotor about 3 feet above the roof line and then go with what mast is safe for lifting onto the rotor at the edge of my roof.  I can easily walk on my roof safely... I am now a pro at that.    I would love to get like 6 or 8 feet above the rotor.. I will buy a 8 footer and cut it down to a size that is manageable.  The problem is I dont have a reference as I have never done this before.

Im more afraid of breaking the antenna climbing up the ladder or falling while getting up the ladder... once I am on the roof that's the next obstacal on lifting it onto the rotor... but I believe this should not be an issue as the rotor will only be a few feet above the roof line..

Well.. this is spring project but wanted to get a jump on the research...

The mast bracketed to the house is fine and I have used such masts. The way to keep it from falling down, and to make antenna installation safer, is to not get greedy and mount the antenna too far above the roof. Four feet above the roof makes the antenna simple to set onto the rotator.
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73

Mike
KD2CJJ
K2MK
Member

Posts: 389




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« Reply #12 on: December 03, 2012, 01:58:56 PM »

When I first installed my Traffie hex beam I had the mast close to the edge of the roof such that about 1/3 of the antenna was always floating about 7 feet over the roof. It's just a normal wood frame house with common shingles. What I discovered was that when the antenna was pointed in the direction of the house the SWR was higher then when the antenna was pointed elsewhere. This was true on all 5 bands. As an example, if the SWR was 1.3:1 pointing away from the house it could be as high as 2.0:1 when over the house.

Overall performance was fine, however, I later moved the mast out into the yard and the SWR is now consistently low in all directions. And for information purposes, the Traffie Hex Beam is smaller in diameter and slightly lighter in weight then the newer style hex beams. I would also recommend a good quality rotator like the Yaesu G-450A. You might also want to join the hex beam reflector:
http://groups.yahoo.com/group/hex-beam/

If you scan the photo section of the reflector you will see many different mounting arrangements. If you see something you like you might see more photos on the ham's QRZ page.

73,
Mike K2MK
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WX7G
Member

Posts: 5917




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« Reply #13 on: December 03, 2012, 03:22:48 PM »

In a 90 mph wind the sideward force on a MA5B and rotator is 80 lbs. Imagine an 80 lb force at the point you plan to mount the antenna and decide if the mast and house bracket will survive.
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KB6HRT
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Posts: 100




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« Reply #14 on: December 05, 2012, 07:12:10 PM »

Hi,
 If you wanted performance I would go with the Traffie  because its the smallest HEX beam, I went with a TMG 26 mini be
an love the antenna, it has a wind load of 1.5 wl against 5 wl  for the Traffie and a tighter turning circle an it works very well for my needs. I also went with a Universal 30' aluminum tower that folds over, the antenna is at 36' when in the air, but can do the work on the antenna on the ground. There are lots of ways to skin a cat, so think thing out good an you will come up with a way that will make you, an your better half happy I'm sure..............KB6HRT
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