PDA

View Full Version : Tower planning



KC2UGV
10-14-2012, 11:26 AM
So, as to not get crazy or anything, I've decided a 30-40ft tower would be more than ample, given my plot. So, I'm debating right now.

My old QTH, the landlord/neighbor (Who is a ham) had an TV antenna tower basically weighed down with cinder brick, and attached to the garage for support. I hazard it's a 25 footer. Can't seen any issue with that way, it worked well there for a number of years. I could go with that, and it would be relatively inexpensive to do, and it would work well enough.

But, I got to looking at US Towers, and I like the idea of a crank up tower. But, I would need a proper foundation for it. For a 30-40ft antenna, what size foundation am I looking at?

ab1ga
10-14-2012, 12:41 PM
You need two pieces of information first:

1. The expected wind loading, which depends on the antenna size mounted on the mast. Manufacturers of commercial antennas usually have this data on their web site, but I remember at least one ham publication (from RSGB) gave a procedure on how to estimate it given the dimensions of the antenna elements.

2. Expected wind speed, which is probably where you have to do a bit of work. I checked the Texas Towers web side for a 40' HyGain crank up. The foundation size specified was 3 feet square by 4'6" deep, for an antenna with 10 sq ft wind loading at 50mph. In Buffalo you may be dealing with speeds much higher than that (even here in Pepperell the design speed is 90mph because of recent hurricane tracks passing within a certain distance of the town).

There are two groups of people who need to be kept happy. The first is the building inspector, who will probably know the design wind speed requirement for your location and will probably call on the town engineer to look things over, too. Having manufacturer's data will go a long way toward getting approval.

The other group is your insurer. Risks are injury to kids due to attractive nuisance and damage to neighbor's property if the mast falls over. Getting a building inspector's approval is essential to ensure coverage, but the insurer may have additional requirements.

73,

W3WN
10-14-2012, 10:00 PM
So, as to not get crazy or anything, I've decided a 30-40ft tower would be more than ample, given my plot. So, I'm debating right now.

My old QTH, the landlord/neighbor (Who is a ham) had an TV antenna tower basically weighed down with cinder brick, and attached to the garage for support. I hazard it's a 25 footer. Can't seen any issue with that way, it worked well there for a number of years. I could go with that, and it would be relatively inexpensive to do, and it would work well enough.

But, I got to looking at US Towers, and I like the idea of a crank up tower. But, I would need a proper foundation for it. For a 30-40ft antenna, what size foundation am I looking at?Off the top of my head, 3 feet by 3 feet by about 4 1/2 feet deep. A touch more than 2 cubic yards.

First things first. Find out what building codes you have to adhere to. What type of permit; whether or not a variance will be required; the whole 9 yards.

W5GA
10-14-2012, 11:18 PM
Corey, for any U.S. Tower manufactured tower, get the mfr's dwg of the foundation, and use it religiously. For my 72', that amounted to a 4'x4'x8' chunk, or if you prefer, 10 yds (one truck). Remember, it's the weight of the concrete against undisturbed soil that holds the whole mess upright.

Also, get yourself a copy of this.
http://www.championradio.com/UP-THE-TOWER-The-Complete-Guide-To-Tower-Construction.1

You won't regret it.

KC2UGV
10-15-2012, 12:28 AM
Good advice all! I guess a trip to the planning office for Buffalo is in order, and ordering a couple of books :)

W3WN
10-15-2012, 07:24 AM
One more thought...

Check with your local Volunteer Counsel, to see if there's anything you need to know that's not obvious. They're often clued in to some of the inner trappings of how government (doesn't) works.

I've gotten a lot of good info from my friend Mike K3AIR, who is also the WPa VC. I probably won't get my tower in this year, but at least I know what to do, and what I can do, and what I should do even if I'm not required.

NN3W
10-18-2012, 06:01 AM
Since you're up in New York, take to W2RE at Hudson Valley Towers. Ray is very very good at what he does.

n2ize
10-22-2012, 09:15 PM
Wind loading is especially bad if you live in Brooklyn or upper Manhattan. We have sustained crosswinds here that will demolish any tower in short order.

XE1/N5AL
10-22-2012, 11:11 PM
Good advice from everyone.

There are at least a couple of threads, currently running over on the Zed, where new tower owners are at odds with their municipal authorities over unapproved erections (which lasted more than 4 hours).

------

Down here, it's a little bit different:

About a dozen years ago, we had problems with water and mud entering the kitchen during Summer's torrential downpours. The kitchen floor would go under a couple of inches of water. A building engineer came out and devised a three-pronged plan to fix the problem. One step involved digging a twelve foot long, by two foot wide, by one foot deep trench in the street, building a cement drain and putting an iron grate over it!

I asked the engineer if we needed permission from the city to do that. He told me, "Yes, permission is required", but he didn't advise asking for it. The engineer questioned me: "What are you going to do if the city says, no?" "You will have to live with a kitchen that floods a few times per year!" He stated that sooner or later, the city would figure out what we had done and issue a fine. So, without city permission, he dug the trench in the street and installed the drain.

Five years later, I received a notice in the mail. It was from the city and they were accusing me of street construction without a permit. The fine for such a heinous deed was going to be 600 pesos, or about $50 USD. I paid the fine and the city was happy. Since the construction, we have never had a flooding problem again!

KC2UGV
10-23-2012, 07:17 AM
Good advice from everyone.

There are at least a couple of threads, currently running over on the Zed, where new tower owners are at odds with their municipal authorities over unapproved erections (which lasted more than 4 hours).

------

Down here, it's a little bit different:

About a dozen years ago, we had problems with water and mud entering the kitchen during Summer's torrential downpours. The kitchen floor would go under a couple of inches of water. A building engineer came out and devised a three-pronged plan to fix the problem. One step involved digging a twelve foot long, by two foot wide, by one foot deep trench in the street, building a cement drain and putting an iron grate over it!

I asked the engineer if we needed permission from the city to do that. He told me, "Yes, permission is required", but he didn't advise asking for it. The engineer questioned me: "What are you going to do if the city says, no?" "You will have to live with a kitchen that floods a few times per year!" He stated that sooner or later, the city would figure out what we had done and issue a fine. So, without city permission, he dug the trench in the street and installed the drain.

Five years later, I received a notice in the mail. It was from the city and they were accusing me of street construction without a permit. The fine for such a heinous deed was going to be 600 pesos, or about $50 USD. I paid the fine and the city was happy. Since the construction, we have never had a flooding problem again!

It generally works like this in the city proper here as well. If I were to go to the permitting office for a 30 ft tower, chances are it would be declined. If I were to install the tower, and the city discovers it, I'll get a fine from $20-$50, and then an approved permit.

However, I'm looking to at least do the construction right, so I've got to ping some other tower owners here in the area, and get the feel for what they did. Heck, after thinking about it for a bit this weekend, I might not even need the tower.

30-40 ft is only 10ft or so above my roofline. With the tower comes issues such as foundation and whatnot. If I were to just stick a mast on my roof, it's way easier, and just as tall. Just not as easy to service. But, that's fixed easily.

Since I use mostly wire antennas, I'm sure I could rig some sort of pulley system to raise and lower the center piece.

W3WN
10-23-2012, 07:25 AM
Well, I don't know about NYS Corey, which is why I suggested you talk to your local VC.

In Pa, though, ever since Act 88 was enacted (state's version of PRB-1), they can't unilaterally decline to issue a permit, especially for a relatively short tower. (I have that direct from K3AIR). That's not to say that they won't, but there have to be good, specific reasons.

Also, the thought occurs to me that if you were to (plan to) mount a small TV antenna on the tower, for OTA HDTV reception, some of the FCC's OTA rules would come into play as well. Just sayin'...

KC2UGV
10-23-2012, 07:33 AM
Well, I don't know about NYS Corey, which is why I suggested you talk to your local VC.

In Pa, though, ever since Act 88 was enacted (state's version of PRB-1), they can't unilaterally decline to issue a permit, especially for a relatively short tower. (I have that direct from K3AIR). That's not to say that they won't, but there have to be good, specific reasons.

Also, the thought occurs to me that if you were to (plan to) mount a small TV antenna on the tower, for OTA HDTV reception, some of the FCC's OTA rules would come into play as well. Just sayin'...

PRB-1 was along the lines of what I was thinking as well. A 30 ft tower is basically a TV antenna tower. Antenna wind load will be minimal, it'll be a wire, not a yagi-uda (lol).

I'm going to get the lay of the land here, so it was good advice. Heck, a permit is free, just takes time, and if I find out the permit is a slam dunk due to height, I'll just go that route, instead of taking the fine.

W3WN
10-23-2012, 08:43 AM
I would not go out of my way to risk the fine. There's no telling how big the fine would be; and it may be more than a fine, it may also be an order to remove the offending structure (ie tower).

I've dealt with some people, over the years, at the municipal level. Can you say "petty tyrants"? Some (fortunately a very few, but enough) are.

N2CHX
10-23-2012, 12:44 PM
It generally works like this in the city proper here as well. If I were to go to the permitting office for a 30 ft tower, chances are it would be declined. If I were to install the tower, and the city discovers it, I'll get a fine from $20-$50, and then an approved permit.

However, I'm looking to at least do the construction right, so I've got to ping some other tower owners here in the area, and get the feel for what they did. Heck, after thinking about it for a bit this weekend, I might not even need the tower.

30-40 ft is only 10ft or so above my roofline. With the tower comes issues such as foundation and whatnot. If I were to just stick a mast on my roof, it's way easier, and just as tall. Just not as easy to service. But, that's fixed easily.

Since I use mostly wire antennas, I'm sure I could rig some sort of pulley system to raise and lower the center piece.

Make friends with your neighbors, bring them lots of beer, then just put the damn thing up. I know a couple of Buffalo building inspectors. They're not going to care as long as no one complains. Yeah you might get a fine sooner or later, but with Buffalo your best bet is to commit your sin and then pay your penance later rather than ask permission. I know I shouldn't be telling you that, but.... The biggest thing in Buffalo is to keep your yard clean and trimmed. Don't leave shit laying around and don't tangle with them over trash/trash pickup issues.

EDIT: I wouldn't go any higher than 40 or 50 feet though, and the smaller face you can get away with, the better.

K7SGJ
10-23-2012, 02:30 PM
Make friends with your neighbors, bring them lots of beer, then just put the damn thing up. I know a couple of Buffalo building inspectors. They're not going to care as long as no one complains. Yeah you might get a fine sooner or later, but with Buffalo your best bet is to commit your sin and then pay your penance later rather than ask permission. I know I shouldn't be telling you that, but.... The biggest thing in Buffalo is to keep your yard clean and trimmed. Don't leave shit laying around and don't tangle with them over trash/trash pickup issues.

EDIT: I wouldn't go any higher than 40 or 50 feet though, and the smaller face you can get away with, the better.


Oh just great. Now he has to have plastic surgery, too?

KC2UGV
10-23-2012, 05:18 PM
Oh just great. Now he has to have plastic surgery, too?

Small? I'd need more than plastic surgery...