ROHN 25G foundation

[John K5PRO]

I started the groundwork to install the Rohn 25G that I took down from a SK's this summer in Albuquerque. The XYL approved the gardenside location, as long as I let her beans climb the tower. Of course, I haven't told her about radials, and since I do the rototilling each spring, I have to figure out how to make this possible on that side of the tower. Or maybe just skip them on that side. It's 46 feet tall, due to a section that I cut off when removing it. Last weekend I cut the legs flat and carefully drilled the matching holes for the 5/16 and 1/4 inch bolts. Got cold galvanizing spray that will be applied later today. Got another free section 8 feet long from local company, as it had been bent at the bottom. This was cut off, and will be the lower section in concrete.

Since I may reinstall the Tennadyne L10 LPA on top (10 ft^2 wind load), I will probably go with 2 guys at each of the 3 anchors. Our local wind peak is 75 MPH, but we don't get much heavy ice. 40 feet, by Rohn data, is OK with one guy, 50 feet needs two. This being all overengineered, of course. Once the anchor is in, and the tensioner is used, it don't matter if I have 3 or 6 cables to hang, just more $$ in materials.

The tower will be centrally located on my lot so that it has about 120 feet on each side to a support - for a center-fed dipole with open wire feeder. This will be a lot higher (44 feet versus 20 feet for my present trap dipole). I can get the ends about 25 feet up in the air also. Tuner will be at the base, and coax underground to the nearby garage shack.

I hope to be able to load it up on 160 or 80, like the OT did before, so that means strain insulators on the guys. The original guys had them, so that's a start.

Before winter sets in, I wanted to get the base in, and the 3 anchors drilled in. So last weekend the hole was dug to spec, 4 feet deep, 2 feet across. Went out to add rebar, and on Tuesday, I found that the #@%&!! gophers had completely destroyed my beautiful clean hole. Tunnels all around it, with balconies, mezzanines! I canceled yesterdays Redi-Mix truck, and today am going to dig out the side chambers, as they are collapsing just as I play with rebar in the hole. Tragedy! I have a gopher noise maker running 100% down in the hole now, and am heading to the store to get a smoke bomb, also have 2 traps in the hole. Once I clean up the mess, the truck has to be there pronto. Any delay and those pesky critters will make my job a lot harder, and cost me another yard of concrete! Anyone else had this problem?

I welcome any comments, especially on tensioning guys and using come-along's with a Chicago wire grip device.

[Mike/W8BAC]

Hi John,

On the foundation I recommend boxing it in with scrap plywood and 2X2's. With soft soil or in your case, critters it will keep the hole clean and sides straight.

For guy wire tensioning try making a loop on the dead end after passing it through the anchor,  with cable clamps (U clamp and saddle) and hook the cable come along to that,  than clamp the come along cable to the guy 4 or 5 feet up and cinch it up.

A better way to go is to use turnbuckles. Use the above method to cinch up the guy  after the dead end is passed through the turnbuckle loop. It helps to be able to fine tune the guys after the foundations settle and the guys stretch. Start with the turnbuckles set at half. Remember to lock the turnbuckles in place with the cable ends or a scrap cable piece after adjustments so vibration won't loosen them.

For safety, NEVER SADDLE A DEAD HORSE! That is never put the cable clamp saddle on the dead end. Only use the saddle of the clamp on the guy. I also recommend using thimbles to soften the cable loops at all the tower, turnbuckle and anchor connections.

Mike

[WA1GFZ]

John,
I have a very modified T12 on top of 7 sections of R25. The antenna weighs about 100 LBs now so almost double stock. Electrical work of art but mechanical hunk of crap. Anyway I have 1/4 inch guys every 17 feet with anti twist brackets. Also double thrust bearing with a 25 foot driveshaft coming down the tower to a tail twister. Mounting the rotor lower makes it easire for the guy wires to keep it stable. It has been up since '97 and had up to about 3/8 inch ice so far. It works very well and pretty flat except for a small range around 22 MHz.

[flintstone mop]

I dug a 4 X 4 X 4 foot hole and sunk a section of tower in the hole. I think Rohn has a tower section for the base. Pour your mix in and let it set-up for a couple of weeks and it should be good.

Fred

[Pete, WA2CWA]

Any delay and those pesky critters will make my job a lot harder, and cost me another yard of concrete! Anyone else had this problem?Huh

I had a frog jump into my tower hole base just before the concrete truck arrived. There's now 6+ yards of concrete above him as a monument.

On quiet spooky nights, I think I can still hear......... 

[k4kyv]

Something similar happened after I had completed the holes for my tower.  Except, instead of critters, it was an unexpected downpour, that even the wx forecaster missed, following a couple of months of extremely dry weather.  The dried out soil couldn't handle the sudden volume of water, so one of the holes completely collapsed, and big hunks off the sides of the others had fallen in.  Each hole was filled to ground level with mud the consistency of chocolate pudding.

I was almost to the point of giving up on the whole project, but I already had all the tower material on hand, so I decided not to quit at that point, and went ahead and salvaged the holes.  First, I had to dip out all the chocolate pudding and dump it far enough away for it not to run back into the hole. Then I filled in the missing hunks on the sides of the holes with a concoction made by mixing a  little portland cement with mud, to a consistency of modelling clay. When the cement set, it solidified the mud to a crunchy hardness, enough to make the repaired sides stable.  Inside the one that had completely collapsed I had to construct a wooden concrete form out of scrap plywood and planks I had on hand.

I had already planned for overkill on the sizes of the guy anchors and tower base.  I didn't bury the bottom section of the tower in concrete. IMO that's a Hammy Hambone method of tower construction.  Better to use a pier pin and base plate so that the guyed tower has some give allowing it to freely sway in the wind, instead of putting all that stress and strain on the tower  structure, although for only 46 ft it shouldn't make a lot of difference.  Mine uses a base insulator, so it had to be ball-and-socket construction in any case.

When the concrete truck had filled all the holes, there was some concrete left over.  The man asked me where I wanted him to dump it.  I thought he would take it back where they would have a place to dump it, but no, it doesn't work that way.  They dump all the  concrete at the customer's site and go back with the truck empty, regardless.  So I decided, instead of having a pile of unwanted hardened concrete  piled somewhere on the property to figure out what to do with, why not just dump the extra in the holes and fill them a little higher?  The original plan was to cover the guy anchors with 2 ft. of soil.  But what would a little extra concrete do, except make the guy anchors even more overkill, so I had him top off the concrete in all the holes, except the one with the wooden form which wasn't made to accept any extra concrete.  So two of my guy anchors have only 8 inches of soil covering the concrete instead of 2 ft, and those guy anchors are 28" thick instead of 12".

I suppose I used sound design and construction, since the tower is still standing after 28 years and numerous high winds.

[WA1GFZ]

Don,
I did the same thing with extra concrete and formed them into round humps.
A lot easier to cut the lawn when you can drive up the side so there is nothing to trim. My tower went up in '77 and reguyed and painted in '97.

[John K5PRO]

I went with the 'hambone' technique of burying tower section in 'crete, because it allows me to climb up and place the first guys (@31 feet) without having temporary guys lower. At least that's what I did taking it down in July. I agree with the suggestion that a pier post and single point base is better as the guys are really doing most if not all of the work keeping that steel in the air. Thats what most AM broadcasters have with guyed towers. 

I cleaned out the hole today, to the full 24 inch dimensions, and the gopher holes are not so bad, they go into the walls a few inches mostly. I think they will just add wings to the concrete mass as it oozes into them. But I am concerned tonight that they don't return as i have it now at the final dimensions before setting rebar tomorrow. My gopher noise maker is running tonight, and I bought some smoke grenades for them, however their tunnels got backfilled today and couldn't toss them in. Feel like Bill Murry in Caddyshack - that was one funny movie - never forgot the grimace on his face when he was trying to exterminate them on the golf course.

I have decided to just order a little extra concrete delivered, like 25%, which will cost me about $40 more. If there is extra after coming up to grade, I have a big hole in the yard, about 5 feet deep, that kid dug years ago, his underground fortress. It never got backfilled, and looks to be the perfect place for the truck to wash out into.

[KA1ZGC]

If you're going to bury a tower section in concrete, make sure you drill holes in the legs where the surface of the concrete is going to settle to allow water to escape from the inside of the tower legs. Even so, the level of concrete inside the legs may be lower than the outside, so you will still be running the risk of the tower legs rotting from the inside out with direct burial.

If you're going to spend the money on the tower and the concrete, the cost of a baseplate and the effort of temporary guys is small. It's cheaper and easier than a tower collapsing on your house (or your neighbor's) and not nearly as frustrating as gophers.

If you do go the hambone route, definately allow for water drainage. It carved the Grand Canyon, taking down your tower is small taters by comparison.

...for what it's worth.

[Jim, W5JO]

If you're going to bury a tower section in concrete, make sure you drill holes in the legs where the surface of the concrete is going to settle to allow water to escape from the inside of the tower legs. Even so, the level of concrete inside the legs may be lower than the outside, so you will still be running the risk of the tower legs rotting from the inside out with direct burial.

Dig the hole an extra 6 inches deep and put about 3" of pea gravel then 3" of gravel down.  Set the legs onto that so water will, hopefully, drain away from inside the legs.

I would hesitate about drilling holes in the legs.  Even though they are small, they can compromise the integrity of the tower.

[KB5MD]

I was told years ago to place about 6" of crushed rock (gravel) in the bottom of  the hole and set the  tower section upon this. It allows the water to drain out the bottom of the tower, rather than drilling holes in the tower legs, which will weaken them.  I have a 50' rohn 25g with  a Mosely TA-33 on top and it has been thru several wind storms during the past 20 years. There are no guys. The tower is made to  stress from the ground. The base is a 3'x3'x3' chunk of reinforced concrete,(about 2.5 tons of weight)
One other thing, tell the readymix guys to add 2% calcium chloride to the mix and it will set up alot faster.  Hope this helps

[k4kyv]

When I put up mine, I used #10 copperweld antenna wire and tent stakes for the temporary guys for the first section.  Then afterwards I used more of the copperweld but attached them to the permanent guy anchors.

I installed the first set of permanent guys at the 30 ft. level, but as the tower grew, I still used temporary copperweld guys every tower section till I installed the next set of permanent ones.  I never felt comfortable working at more than one tower section above a guy point.  I could stand on the ground and look at the tower and say, no way anything is going to  give way @ 2 or 3 sections above the guy point and I could safely swing on it like a trapeze artist, but when I climbed the tower it was an entirely different perspective. The top guy section appeared to be a long way down, and the tower would sway with my every move, and if I tried to lean back in the climbing belt it felt like the whole thing was coming down with me on it. No way;  I had to stabilise it with something.  About the only thing those temporary guys did was to stop the movement and make the tower seem more solid and stable, but that made me feel a lot more comfortable working.  Purely psycholoical, but that's crucial, since being less than fully at ease, in itself, can make a job like tower erection hazardous and vulnerable to human error.

As for drilling drain holes, if the tower is to be guyed, that shouldn't be a problem if the holes are kept small. The guys are what keeps the tower vertical, and although the tower will be stressed under wind conditions, it shouldn't be enough to cause a catastrophic failure.  Even if the tower broke completely in two (virtually zero likelihood), the bottom would still simply drop to rest on the concrete base and the guys would still hold it up.  It would take a tremendous lateral  force to displace the base of a tower, even if it were not anchored to anything, considering the downward force caused by the weight of the tower and antenna, plus the downward vertical component of the tension at each guy wire.

If the tower is to be self-supporting, I would be leery of drilling any kind of holes in the legs.  But in that case, it would be much better to purchase real self-supported tower components.

[K1JJ]

Maybe it was already mentioned here somewhere -  (I didn't see it) for the main reason to use a base pin and floating base on a guyed tower - might as well emphasize so nobody makes the same mistake I did...

When the bottom section is placed solid in concrete, there is no way to get the guy wires perfectly balanced to produce no stress on the bottom section. Even if tensioned perfectly, guys stretch over time, wind storms occur,  and there will be uneven stress on the lower section in concrete. This is like a lever and can snap/fold the legs right at the base.  The biggest stress is right at the point of coming out of the concrete.

With a floating base pin, the tower base can rock slightly and compensate for guying and wind pressure changes. If you think about it, the top of the tower is also free to move about, which is a good thing... :-)

Back in 1985, my first tower was a 150'er Rohn 45 with its base placed in solid concrete. A fool at a popular ham store recommended it... :-)  I didn't know any better myself. Years later in 1994 I loosened the turnbuckles and used a hydralic jack to raise the tower a few inches - I cut the three legs and inserted in a base pin and plate.  Quite a job, but it worked.


Yes, John, go with turnbuckles. Tweaking the guys every year or so is part of tower maintainence. After a big wind or ice storm, you will find they probably need a some minor adjustments.

It's amazing how much vertical weight a guyed tower can take. For example, if each Rohn 45 guy is tensioned to 600 pounds, this is 1800 pounds per set. Multiply this time five sets and you're pushing upwards of 10,000 pounds including the tower weight.  (The guying weight load is somewhat less cuz of the angle not being straight down) The  tower needs to be very straight to handle a big load like this. Curve it or torque slightly and this rating drops markedly.   Torque on a tower is the big killer and why many come down.  I built up homebrew torque-arms for all of my guyed towers. (6 guys per level) This really helps when rotating a big load.

It pays to develop a good eye and sight straight up the tower to see which sections need guy adjustments. After some time, the tower can be tweaked very straight using your eye. Another way is to borrow/rent a transit.  Set it up two hundred feet away from the tower and sight right up the rail. Do this from each 120 degree leg angle view. (Three times)  Using this method I was able to find one of my guyed towers had straight section alignment, but leaned about 2 inches from center of gravity... :-)  No other way to do this... even the level didn't show it.

Good luck.

73,

Tom, K1JJ

[WA1GFZ]

A friend not wanting to waste 5 feet of tower in the ground welded a frame with 3 vertical solid pins to hold the bottom section. This way water could drain around the pins. No, do not drill the bottom of a tower leg the hole will rot the leg in time.. Set it in stone so water can drain out.
Three pins seemed easier to deal with than a single center pin. I don't have my guys that tight Tom but I'm not kissing the clouds either. I just have my guys snug so it doesn't move. Reminds me I have not checked mine in a while.
I look up under each set of guys to make sure each level lines up. It is easy to make the structure straight.
knock on wood after 31 years. Guy anchor is where you want lots of concrete not so much the tower. As the tower moves it wants to pull the guy out of the ground or set the tower deeper in the ground. 

[WQ9E]

OK,  John is putting up a fairly short tower consisting of Rohn 25, not the Eiffel tower.  Properly installed, a short base in concrete will work just fine for him.  Rohn designed short concrete bases for Rohn 25, 45, 55, and 65 series tower and if they are installed with proper gravel for drainage they will last as long as the rest of the tower which is a very long time indeed.  The biggest reason for using a pier pin installation is for very tall towers so that any deviation from plumb in the base is not transferred as a stress factor throughout the rest of the structure; that isn't going to be an issue with 50 feet of tower unless John chugs a fifth of bourbon before installing the base.  Just make sure your holes truly are properly spaced and the pipe tops are properly flattened and then use your level across the tops of the legs.

The funniest (since I didn't live anywhere near it) and worst Rohn 25G installation I am aware of was a CB type who obviously leveled across the rungs instead of the tops of the legs and the base was far from level.  He followed that up by using nylon ropes for guys and tried to pull it straight with those stretchy ropes.  A friend in the city engineering office later told me that they investigated after concerns from the neighbors and also found the guy anchors consisted of 3 small block chevy V-8's buried just below the surface with an eyebolt threaded into one of the head bolt openings-this was probably the strongest part of the entire installation.  By the way this was in Gulfport MS down in hurricane country.  

John,  If you need specs, diagrams, etc. for you 25 installation PM me.  I still have the Rohn commercial products catalog I got when I installed my 55G around 15 years ago.  It has all the basic information, specs, etc. necessary for installation and I can scan and email you what you need to set your mind at rest.  If you have an accommodating Rohn dealer nearby you can probably acquire your own copy and it is a handy reference guide.

Rodger WQ9E

[KA1ZGC]

I don't have my guys that tight Tom but I'm not kissing the clouds either.

Have you seen Tom's guy anchors? You're right down the road, so I'm guessing you have. You could hold back a Saturn-V rocket with one!

The funniest (since I didn't live anywhere near it) and worst Rohn 25G installation I am aware of was a CB type who obviously leveled across the rungs instead of the tops of the legs and the base was far from level.  He followed that up by using nylon ropes for guys and tried to pull it straight with those stretchy ropes.

I know a 2M-CB kinda ham on the coast of Maine who put up something like 120' of tower. I forget exactly what kind of tower he used, but he figured he didn't really need to guy it if he went up the tower and welded the sections together. As an afterthought, he decided he probably should guy it after all, so he attached ropes (probably nylon) at 35' or so and tied them around nearby trees.

The amazing part was that it took a little over a month for the tower to come down and just barely miss his house. He got absolutely zero sympathy from any of us.

A friend in the city engineering office later told me that they investigated after concerns from the neighbors and also found the guy anchors consisted of 3 small block chevy V-8's buried just below the surface with an eyebolt threaded into one of the head bolt openings-this was probably the strongest part of the entire installation.

...all except the eyebolt. I help Timtron bury an engine block as a guy anchor for the short frankentower behind his trailer. We ran the cable right through a cylinder or two and cable-clamped it back on itself (appearently nobody makes preforms that will fit a chuffa-block).

Burying three complete engines, and then relying on the shearing strength of eyebolt threads (which I doubt would be grade 5 or grade 8 steel) strikes me like busting your ass the wrong way around, but certainly no dumber than the rope guys.

[John K5PRO]

Wow, quite a diversity of tower advice here. I have an old Rohn catalog so have all the info I think i need. Thanks for offers though.

OK, here's my design, concrete is scheduled for Tuesday AM. Today I finished out the square hole, It tapers bigger at the bottom, about 31 inches across and 24 at the top. This wasn't planned, but oh well. It has vertical room for 6 inches of gravel and sand at the bottom, and the top of the block about 5 inches above grade. The overall concrete height will be 4.5 feet. I put four 6 x 8 x 8 solid blocks on the gravel, to support a rebar cage. Four four foot pieces of #6 (3/4inch) are vertical on the corners, sitting on these blocks. Around these are five pieces of #4 bent into squares. All tied together with wire, this frame then lowered into the hole, and the tower sites inside the center. The tower legs poked down into the gravel bed to drain, and then some sand was tamped on top to help prevent cement from dripping through and sealing up the bottoms. I used cold-galvanizing spray, two coats, on the lower ends of the cut 8 foot section. The rebar cages is held 3 inches above the bottom of the foundation block. I plumbed the base section as well as using a long vertical level on all three legs with a wire "Y" tied across the legs, and a bolt hanging from a string. Once it looked true vertical, I staked and tied some big ropes to the upper end (this is an 8 foot piece of 25G, my base section). Tensioned it and then tied the rebar cage to the tower in a couple of places down the hole, so that it won't shift around in the hole during pour. A wooden form above grade finished the preparation. It comes out to 0.9 yards of concrete needed, so I will get a yard. I have some steps for the garage that I am going to also make, so will get more than that though.

Will be careful to get it plumb to the top, and equal-tension the guys. I have 3/16 EHT cable and am attempting to hire an electrical contractor who has a power auger on this truck, to drive in three big screw in anchors, the 6 inch helix with 66 inch steel shaft. I may spring for a tension gauge.

My other tower, a Universal aluminum self standing at 30 feet, has a 3 x 3 x 4' concrete base, next to the house, holding triband yagi for SSB and end of dipole, plus a UHF TV yagi and a Canopy WIFI suscriber antenna. I installed it in 1993, got it for nearly nothing from an old ham. It was so easy to install, lightweight, no guys. Didn't even use a gin pole, just muscled everything up there. It will continue to be an end anchor for the long dipole. Center will now be up this 46 foot 25G. Presently my trap dipole is only 20 feet high at center!

What became of the gopher... Well, as i was digging out the bottom of the hole today, I found Mr. Gopher dead in the dirt. Seems he was hiding there yesterday when I was cussing and found his tunnels. Before quitting for the day, I had dropped a big concrete block into the hole. I guess he was just under the soil and got smashed! My good fortune. Turns out that his tunnels were only superficial, a few inches deep in the walls of my hole. So I will let some concrete flow into there. I put a sonic gopher repeller in the bottom for the night, it is 90 decibels of horrible pulsed sweeping tones. Put a blanket around the tower so that the neighbors don't think their is a UFO landing over here. Hopefully those gophers will stay away until the pour....

Will feel a lot better once the concrete is setup and the first section is plumb. I have a lot of other work to do before putting up the rest of the tower, and daytime weather here in NM is excellent in November, usually.

[WQ9E]

John,

It sounds like you have a good plan and your base is going to be plenty stout.  Do be prepared to check/level the base during the pour as the concrete guy may try to dump most of it in a hurry so you may have to slightly adjust the base during/immediately after the pour.  I assume your soil is suitable for the screw anchors, your contractor should know.

Unless you have future plans for a lot more tower installations you don't really need a tension gauge.  As long as you don't try to put a crazy pre-load on the guys the gauge isn't really needed until you start trying to properly tension the very large diameter EHS cables.  I have a fairly expensive Starret tension meter for my bandsaw blades that I could probably use to tension my guywire also, I will have to try that out next time I do some tower maintenance.

Don't forget the ground rods!  As to breaking up the guy wires with insulators, the only Rohn 25G I have personally witnessed failing did so after an apparent lightning strike shattered a pair of insulators on one of the top guys and the change in tension caused the tower to fail.  I have a feeling that all of the guys may have had excessive pre-load which led to this failure but that is purely a guess.

Safe climbing!

Rodger

[WA1GFZ]

I used screw anchors with 2 yards of concrete on top of each one.

[k4kyv]

It may be difficult with only 46 ft. of tower, but I tension my guy wires by eye.  I go by the amount of sag, and make sure the sag on each one at a particular guy level is exactly the same.  I don't over tighten them or leave excessive amount of slop.  Be sure to check during any extreme cold periods, since metal  wires contract with cold and expand with heat.  To me, it's pretty easy to judge what is too tight and what is too slack.  IIRC, there are instructions in the 1960's vintage NAB broadcast engineers handbook on how to estimate the tension in pounds by the amount of sag.

I found out the hard way about contraction at low temperatures.  My open wire line running up the tower is tensioned with a set of small turn buckles.  I had them set  on the tight side, and a couple of years ago the temps dropped to the single digits (haven't seen sub-zero here in over 15 years), and it pulled one of the small ceramic "dog bone" insulators in two.  My temporary replacement, a bundle of scrap Phillistran held in place with plastic ties, is still in place and seems to work as well as the insulator.

Those guy wires with the  failed tower must have been way overtightened.  Normally, that's the way strain insulators are supposed to work; the loops of wire catch and hold the wire together in the event of an insulator failure.  Perhaps there was a strong wind coming from the same direction as the guy wire creating excessive tension when the lightning hit, and the shock wave was enough to cause something to snap.  Or something else may have failed under a heavy wind load, completely unrelated to the broken insulator.

Instructions say to tension the guy line to 10% of breaking strength.  I borrowed a tension gauge when I put up my tower, and  the proper figure, 500 lbs of tension on my 3/16" EHS cables seemed excessively tight, so I loosened them to a more reasonable feel.  Supposedly the purpose of the 10% figure is to hold the tower immobile and prevent it from swaying too much in the wind.  I would set them at the 10% figure maybe during a record cold snap, but surely never during the summer.  I think mine are only tensed to about 5% of breaking strength, and they still seem plenty tight.  And the tower has held up for nearly 30 years. 

Also, some guy wire materials the same size and weight have different breaking strengths.  For example, 3/16" HS (hardened steel, or high strength?) is rated at 3000 lbs breaking strength, while the EHS (extruded hardened steel ,or extra high strength?) is rated at 5000 lbs.  Otherwise the physical characteristics are very similar, except that HS is less springy, less brittle, a real pleasure to work with compared to EHS, but the only thing I have seen on the market for the past 30 years is EHS.

Another time I'll post a message explaining how I came way too close to losing an eye while working with EHS guy wire.

[WQ9E]

Don, as usual, raises some great points and in particular be very careful with the guy wire as it is very springy stuff.  I use 1/4" EHS (I believe EHS at least in Rohn speak is Extra High Strength) and I ALWAYS wear safety goggles and leather gloves when handling the stuff.   3/16" is probably a little less of a pain to manage but still go for safety. 

If you use the U type guy clamps instead of dead ends, particularly with 1/4 EHS, it is easiest to install the clamp that goes furthest from the loop first.  The first clamp helps capture the wire into a manageable loop, you can then loosely install the others and slide them forward to create the fairly tight loop around the turnbuckle/insulator/torque bar attachment point.  Don't forget to properly serve the ends if you use clamps.

If you do use Phillystran or similar follow their recommendations and use regular galvanized steel for the final few feet close to the ground anchor to prevent damage from fire/animals/vandals.  Always loop and secure a piece of guy wire through the turnbuckle to prevent it from loosening under vibration and to discourage someone from playing games with your tower.  The turnbuckles with just a hook in one end are NFG, under the wrong conditions of wind and under-tensioned guys they can come loose.  They must be good for something since you can find them at the farm stores around here and they are otherwise sturdy but definitely not good for our use.

Don, I am pretty sure that the guys were severely over tensioned (the tower was owned/installed by a use a bigger hammer type guy) and he also had a TH7 and some sort of 2 and 6 meter interlaced beam stuck on some pretty tall mast on top so he was probably at/over the ratings for 90' of tower.

[John K5PRO]

The concrete got delayed until today, as I also set up to pour two steps for the 2 doors into the garage. This is on a slab, and I drilled into it, then set rebar with concrete epoxy, so that the steps don't detach from the building. No more gopher attacks.

A cold front came through, and it was 13 deg F in my yard this morning. Luckily, by 9 it was nearly 35 and rising. Poured 1.75 cu. yards and had only a wheelbarrow full left over from the truck. The 25G tower base section looks fine. I can't detect any deviation from level, on all three legs, using several levels. My plumb string didn't work as it was blowing wind all morning. Leaves coming down in droves, trying to mess up my concrete. I had CaCl accelerator in the mix, so it is setting up nicely. Gotta run and trowel steps now, photos will be posted later.

[WA1GFZ]

I put roofing tar around each leg on top of the concrete so water can't leak in around the tubes. Wait till it drys a few days. No cracks after 31 years.
KOW.

[WA1HZK]

A famous union boss disappeared after my last foundation was poured.......

All the 25G drawings are posted here:
http://www.criticaltowers.com/ROHN%20Industries/Media/pdfs/25G/25gtowers.html
That will give you the factory recommendations.
Keith
WA1HZK

[John K5PRO]

Here are three photos taken this AM after the pour. We are expecting single digit temperatures tonight, so everything is covered with blankets now. What happened to autumn?