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Message |
    
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 259
Registered: 4-2002
| | Posted on Monday, March 29, 2004 - 5:05 pm: | 
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I have about hopefully another month and then this 35 foot tower is going in concrete. We just sided the house so I can't have anything attach to the house but was wondering how much concrete and how deep and how wide of a hole will this 35 foot tower hold into? I was thinking about 3 feet wide and about 3 feet deep. Is that enough? Reason I'm asking this is because I thought about putting up my penetrator and those take a little more wind than an imax 2000. Don't want this to take some wind then fall over because it was a little top heavy.
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Bruce
Senior Member
Username: Bruce
Post Number: 1096
Registered: 9-2003
| | Posted on Monday, March 29, 2004 - 5:58 pm: |
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Boxcar ....
My tower in 1976 was in a 3 foot by 6 foot deep block i would check with the tower maker and MAKE SURE you have enough. |
Ca346
Advanced Member
Username: Ca346
Post Number: 664
Registered: 8-2003
| | Posted on Monday, March 29, 2004 - 6:09 pm: |
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I believe in overkill. My tower is in a 4'x4'x4' hole with 1/2" rebar every 1 ft. My tower is 50 ft however. But the wind loads are severe sometimes here and I wanted to ensure it stayed there! I also have it guyed (wire) at the 42ft height. Go to the Rohn tower website for a quick download of spec's on different tower heights. Don't forget grounding rods...
You should have no problems with your 35ft tower with a 3x3x3 conc. base. Is it free standing? Do you know the wind load of the antenna's you are putting up? |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 259
Registered: 4-2002
| | Posted on Monday, March 29, 2004 - 10:01 pm: |
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Ca346, Yes, it's a free standing tower. I've never had to guy wire anything except the poles that come out of the top just to be on the safe side. The windload on the antenna is about 90 miles an hour. I think! Not sure if I remember right about those old penetrator 500's. I'm either putting that back up there or a new imax 2000 that I bought off of copper just a while back. I bet i'll need a permit though.
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Ozzie
Intermediate Member
Username: Ozzie
Post Number: 155
Registered: 11-2003
| | Posted on Tuesday, March 30, 2004 - 9:17 am: |
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3x3x3 SHOULD be enough but I agree that more is better.. My old 45ft tower (left in Australia) was in a 3x3x3 block of concrete with enough fibresteel reo to do a 60x30x6" workshop floor. On top of that the tower support frame weas then dyna-bolted into the rock shelf that run under half the town.
One day I'll have to visit and see what the new onwers of that house did with that concrete block because it sure wasnt coming out. |
Ozzie
Intermediate Member
Username: Ozzie
Post Number: 156
Registered: 11-2003
| | Posted on Tuesday, March 30, 2004 - 9:19 am: |
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PS.
If possible tie the concrete into the concrete foundations for the house. That helps too. |
Pig040
Intermediate Member
Username: Pig040
Post Number: 359
Registered: 7-2003
| | Posted on Tuesday, March 30, 2004 - 9:37 am: |
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I have my 40' tower in about 3x3 block of concrete, but with the winds here I made sure I used good guy wires, I would never try to have it free standing in a windy area, unless it was truly a free standing design. |
Cm3885
Intermediate Member
Username: Cm3885
Post Number: 308
Registered: 12-2003
| | Posted on Tuesday, March 30, 2004 - 1:27 pm: |
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My 40' tower is in a block of 3x3x3 and its not a freestanding tower its an American tower guyed to the trees and the garage roof. Been up 10 years with a set of rakers and no problems. |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 260
Registered: 4-2002
| | Posted on Tuesday, March 30, 2004 - 4:21 pm: |
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Maybe I'll just have to make sure I get some rebar in the ground real good to give it some extra support. I guess we'll find out when I get it done and climb up it and shake on it like a monkey swinging in a tree then if she falls down, I will know! LOL!!!!!!!!! Somebody got a bandaid?
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Ca346
Advanced Member
Username: Ca346
Post Number: 668
Registered: 8-2003
| | Posted on Tuesday, March 30, 2004 - 5:30 pm: |
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Don't forget the pictures! Get that wife or girlfriend out there to take pictures of the event. My wife was taking pictures of my hair raising event and I still look at them and get chills...
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Boxcar
Intermediate Member
Username: Boxcar
Post Number: 261
Registered: 4-2002
| | Posted on Tuesday, March 30, 2004 - 6:58 pm: |
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Hey Ca346, I do have a few pic's that were pretty scary from past incidences. I will tell you a story why I get nervous when I have to deal with this hobby it still spooks me to this day. When I first got into this hobby, I was able to find a fire deparment that was no longer using their tower so I had stopped in to ask if I could purchase it from them to which they said take it down and don't give us anything for it. Down it went and had paused about a month before I was going to figure out some way to put it back up. Easier taking it down than putting it up, that's for sure. So, I had my 2 cousins stop over and help out. So up it went and I had climbed to the top and strapped myself to the pole using an old leather weight lifting belt to keep me from visiting the heavenly gates. I had took a 9 foot pole and loosened the bolt and slid it down on top of my foot enough so I could get the top pole in that had the antenna on it, in doing so my foot was getting very tired so I switched feet and put the other foot inside NOT realizing that the pole was still loose sitting on top of my foot, it slid past my foot and down the middle section of the tower. Down it went until it hit the top of one of my cousins foot right smack dab in the middle of the top of his foot causing him to yell some pretty choice words. I had shoved the antenna in the top, bolted it down all within seconds so I could release my belt and see what damage it had done. When I got to the bottom, the pole had hit the top of his foot causing half of it on his foot, the other half hit into his sandle(yes, stupid shoes for that occasion). There was a chunk about a 1/4 inch deep that needed some hospital attention. No stitches required because it stopped bleeding right away but from there on, I promised myself I would take all measures in rehearsing any future tower improvements and make safety the biggest factor. Have not had any other downfalls and it's a good thing!!
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Dindin
Junior Member
Username: Dindin
Post Number: 38
Registered: 2-2004
| | Posted on Tuesday, March 30, 2004 - 11:30 pm: |
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Boxcar,I read your post and I shuddered at the thought of something like that happening!Another thing you mentioned was the belt you used.While I commend you on the idea,ask yourself "was that belt designed for that?"Any one doing tower work,no matter how high should only use a saftybelt designed for that purpose!Would that weightlifting belt actually have supported you in a sudden slip?I have a Miller climbers belt I have used for over20 years and 2 years ago,had factory inspected(still good as new).Myself I would not myself or let anyone else working for me go up a tower unless properly equipt to do so.That would also include a tool bag or linemans pouch to carry tools and hardware.Also NEVER do tower work alone.Be sure those on the ground are keeping an eye on whats going on over head.(You could probley imagine what it would be like to get hit in the head by a 2 pound ratchet from 50 feet or so)With spring here I'm sure lots of you are ready to do some antenna work weather its erecting that new Imax youve had in storage since Christmas,repairing winter damage,to trying a homebrew idea.Lets keep this hobbie or livleyhood SAFE and enjoyable.I would hate to see any of my new or old friends leave the hobbie over a mishap that is preventable.Be safe and 73's from my home to yours! |
Ozzie
Intermediate Member
Username: Ozzie
Post Number: 159
Registered: 11-2003
| | Posted on Wednesday, March 31, 2004 - 8:58 am: |
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CM,
Once dropped a N-type connector from the top of a 110ft tower. It embedded itslef into the hard clay some 15 feet out from the tower. Needless to say that connector was also useless after that. |
Pp1616
Member
Username: Pp1616
Post Number: 64
Registered: 2-2004
| | Posted on Wednesday, March 31, 2004 - 10:50 am: |
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when u guys did your towers did u mix your concrete youre self or have it brought in??? and does any one know the min amount u can get if u have it brought in. reason asking is thats kinda a big hole u have to fill lol and im going to be puting one up in a month or 2...thanks
cef #301 |
Ca346
Advanced Member
Username: Ca346
Post Number: 672
Registered: 8-2003
| | Posted on Wednesday, March 31, 2004 - 11:51 am: |
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I took several weeks to dig the hole (4x4x4) and then used alot of rebar and tie wire. I also drove my two ground rods (diagonally opposed)in next to the foundation before filling with concrete. (Note Tech808 will tell you 4 grnd rods on his...). My hole calc'd to be 2.4 Cubic Yards of conc. I ordered 2 1/2 and was happy. Conc was $50 a yard delv'd. I rented a "stinger" (vibrating rubber coated 4ft long) and boy was that a good investment! Truck backed up to the hole and was gone in 20 minutes. |
Cm3885
Intermediate Member
Username: Cm3885
Post Number: 310
Registered: 12-2003
| | Posted on Wednesday, March 31, 2004 - 12:36 pm: |
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I got mine for free! I called the local concrete place and they sent over the truck and gave me some for nothing.. Thing to do is call the place that does conrete jobs and see if they have a big job they are doing. If they are doing it late in the day and they have some left over they will usually just dump the extra out somewere and wash out the drum in the truck. If you can get them to come by you if you are close to their route they will usually give it to you for free.. Then they dont have to worry about dumping it somewere.. |
Pp1616
Member
Username: Pp1616
Post Number: 67
Registered: 2-2004
| | Posted on Wednesday, March 31, 2004 - 1:56 pm: |
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i got a small backhoe i can use =) come in handy.. thanks for the info ca346 that just what i needed.. |
Pp1616
Member
Username: Pp1616
Post Number: 70
Registered: 2-2004
| | Posted on Wednesday, March 31, 2004 - 3:10 pm: |
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any buddy know how many 100lb bags = 2.5 yards hehehe |
Ca346
Advanced Member
Username: Ca346
Post Number: 674
Registered: 8-2003
| | Posted on Wednesday, March 31, 2004 - 4:35 pm: |
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A bunch! (That's more than a passel) |
Dindin
Junior Member
Username: Dindin
Post Number: 39
Registered: 2-2004
| | Posted on Wednesday, March 31, 2004 - 5:31 pm: |
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PP1616,27 90 pound bags of Sackrete to a cubic yard so;68 bags,portable mixer rental,back ache....Hmmm....call your local readymix plant! |
