Where to put my 50ft tower? Up high close to trees or lower and far from trees? - Page 1
Forum section: electronics / rf-microwave

author: W9GFO
author_rank: Regular Contributor
timestamp: March 31, 2018, 01:46:57 am
content: I just got a pretty good deal on a 50 ft self supporting, tilting, crank-up tower. I now need to decide where to put it. If I put it near the house then it is in fairly clear space with the nearest trees about 150ft away. Or I could put the tower about 250 ft away from the house and about 35ft higher but there would be trees just 30 ft away on two sides. Our property is on about a 10% slope. I'll start with just a 2 meter antenna on it but will probably want to go into HF in the near future.So near the house is convenient but I think the extra 35ft of altitude is worth the inconvenience. There is also my neighbor, If I put the tower closer to them (at the higher altitude) it will be hidden from their view by a tall tree, if I put it near my house it will be more visible to them. What would you do?

author: TheSteve
author_rank: Unknown
timestamp: March 31, 2018, 06:35:29 am
content: Before considering putting the tower 250 feet from your house do some research on the cost of coax cable and the loss it will introduce. The 35 feet will likely get you no return on HF, on VHF it will help but the loss in the coax will outweigh any gain unless you go with some expensive stuff.To sum up - put it near the house.

author: Wirehead
author_rank: Regular Contributor
timestamp: March 31, 2018, 04:31:03 pm
content: Or turn the statement around, putting it further from the house, less QRM

author: TheSteve
author_rank: Unknown
timestamp: March 31, 2018, 05:57:23 pm
content: Quote from: Wirehead on March 31, 2018, 04:31:03 pmThat is also a consideration. However I'd be much more comfortable keeping the tower close to my house and as far away from the neighbors as possible. I can control the QRM from my house, I can't control it from a neighbors.

author: W9GFO
author_rank: Regular Contributor
timestamp: March 31, 2018, 10:49:43 pm
content: True that I wouldn't want to run 250 ft of coax. I was thinking I would put a small shack next to the tower with some solar panels and other equipment, possibly making it big enough to be the ham shack or keep it small and operate remotely using a cross band repeater. "Near" to my neighbors is relative, I should have said that it would still be 200ft from their house if I put it at the higher location.I don't really want it near our house unless there is a significant benefit to it being there. Since we live on a slope, when you first enter the property you can't see the house because it is lower, but you would certainly see an antenna tower and it would be a bit of an eyesore. Placing the tower up high near the entrance to the property would mostly keep it out of sight. You would only see it when approaching the property along the shared driveway. Even then it would only be visible through a small gap in the trees....and I just spent some time in Google Earth and did a bunch of math and discovered that to achieve LOS to the Gold Mt repeater I need the antenna to be 356 ASL or 62 ft AGL if the tower is placed at the higher location. But, sitting in my house I can work that repeater using my HT on VHF even though there is a 120 ft hill a quarter mile away between me and Gold Mt - which is 12 miles away. Even UHF works if I step outside the house. I guess LOS isn't as important as I have been lead to believe.What I am having trouble finding information on is how the signal (esp VHF and above) is affected when going through trees that are close by vs. having more airspace before encountering trees.

author: Nusa
author_rank: Super Contributor
timestamp: March 31, 2018, 11:21:19 pm
content: If you have already trees that are that tall, have you considered mounting an antenna at the top of one? That's often far cheaper to install and will last a long time if done right.Are there any zoning laws that might come in play if someone invokes them? If not, I suggest simply asking the neighbors if you really care about their opinion on the matter.

author: GreyWoolfe
author_rank: Unknown
timestamp: April 01, 2018, 02:11:53 am
content: I would certainly never consider a tower of any type an eyesore, even though SWMBO would. That said, closer to the house, shorter coax run, less loss, especially on VHF. 'Nuff said.

author: W9GFO
author_rank: Regular Contributor
timestamp: April 01, 2018, 04:33:03 am
content: Thanks for the replies. The consensus seems to be close to the house for shorter coax runs, but close to the house for me would be near the shop which is about a 60ft run - although the shop could become the shack so the short run argument still applies I guess.Mainly what I am trying to figure out is how being close to trees affects the signal and if that is a reason against putting the tower at the higher location. If I do put it up there then I will also put a shack next to it for the shortest possible coax run. In my searching I have not come across any information on trees in close proximity having an effect so I am leaning heavily toward the higher location, unless I learn that I would get a better signal by moving 100ft further from the trees and 35 ft lower.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 01, 2018, 05:18:40 am
content: Quote from: TheSteve on March 31, 2018, 06:35:29 amWith the disadvantage of having electronics outdoors (condensation and whatnot), you could put the RF front end as close to the antenna as you practically can, then route power and signals back to the lab. That's regularly done at microwave frequencies since the cable losses quickly become unreasonable with any real distance.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 01, 2018, 01:29:28 pm
content: Quote from: W9GFO on March 31, 2018, 01:46:57 am...Can you use the System who 97% of the People in the World use?I have no clue what you talking about! You are VERY rude!

author: donmr
author_rank: Regular Contributor
timestamp: April 01, 2018, 03:19:11 pm
content: You might want to look at the article in the Feb 2018 issue of QST about the affects of trees on antennas and signals. Short answer, yes trees can have an affect.

author: Nusa
author_rank: Super Contributor
timestamp: April 01, 2018, 04:10:09 pm
content: Quote from: Lord of nothing on April 01, 2018, 01:29:28 pm97% is high. The US has 4.4% of the worlds population, plus there are still other countries that still use the units regularly while being on the metric standard. Started to happen in 1975, but politicians torpedoed it a few years later. I agree we should convert, and in some areas like food packaging it's happening anyway. The final policy steps will probably have to wait for more of the old guard to die off.In any case, Google is your friend. "150 ft in m?" will set you straight. Is that too hard to do in the spirit of international understanding? It's nothing compared to having learned English in the first place, I suspect, and only about 20% of the world speak English. [Side note...long ago my father learned to read German solely because a number of significant books in Chemistry were not translated at the time.]Or if you want to do it in your head, dividing by 3 will get you yards, which is close enough to a meter for ballpark purposes.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 01, 2018, 04:27:33 pm
content: Quote from: Nusa on April 01, 2018, 04:10:09 pmThe other2 Country are Liberia, Myanmar....

author: Nusa
author_rank: Super Contributor
timestamp: April 01, 2018, 04:39:57 pm
content: Quote from: Lord of nothing on April 01, 2018, 04:27:33 pmOfficially, yes. But I was thinking of places like Canada, Mexico, Australia, the UK...all places that mostly understand feet and inches, even if they aren't "officially" using them anymore. In practice, the switch takes a few generations before the old units are unfamiliar, no matter what the laws say.

author: W9GFO
author_rank: Regular Contributor
timestamp: April 01, 2018, 07:53:02 pm
content: Quote from: Lord of nothing on April 01, 2018, 01:29:28 pmMay I kindly suggest that you review theforum rules, #1 and #2 in particular, and I will keep #4 in mind.

author: W9GFO
author_rank: Regular Contributor
timestamp: April 01, 2018, 11:16:48 pm
content: Quote from: donmr on April 01, 2018, 03:19:11 pmThis is the type of info I was after. Thank you. It looks like if I stay 10m away from the trees that the effect will be minimal, moving 30m away would nearly eliminate the effect, but then the 10m loss in height is probably worse. Also, at the height of the antenna the size of the trees is pretty small. The trees that are near are just a little taller than the tower.

author: denverpilot
author_rank: Regular Contributor
timestamp: April 02, 2018, 07:52:49 am
content: Also I wouldn’t base your tower location on hitting an FM repeater. You’ll find you can simply do simplex work with a good tower. You can put a pole up for VHF/UHF verticals. Save the tower for stuff that goes on towers. Rotatable, awesome stuff. Think big antennas here. Directional antennas.Make that RF go somewhere.Also keep in mind as you head into HF yagis and such that you need some swing room for the antenna on a rotor. In other words, don’t put it up against the trees. Even large 6m yagis and long boom VHF+ stuff takes a lot of feet of swing radius.Think about how you’ll erect and lower antennas that big and where they’ll have to sit for hoisting and lowering. Not just how to get the tower up. Trust me in this.Rigging large antennas up where you have to hoist them to a roof and then up again is a pain in the rear. But hoisting them through tree branches is an exercise in loud cursing and never having any friends over to help with your tower work ever again.Buy hard hats. Have extras. Don’t let anyone near your tower work without one on. Send them home if they won’t comply.And think about your climbing gear and learn about what the pros use and use it. Including fall arrest gear. And get someone in the tower biz to train you on its use. Don’t be the doofus hanging from a 1970s vintage leather lineman’s belt. Get a proper harness. Note: This stuff isn’t cheap. But used properly it will save your life.I think you mentioned it’s a fold over. You’ll be surprised once you have coax strung up it or even hardline how little you’ll want to crank it over to work on it. But make sure there’s space. On large antenna stacks (if what you have for tower size will handle large wind loads) once the tower is tilted any wind from the side is acting as a twisting force at the base.You WILL have to climb it whether it is a fold over or not. And in some conditions you CAN’T fold it over. So be prepared to do antenna work like a normal non-foldable sometimes. Often folding it down will just take incredible amounts of time and lots of care, when a safe climb with proper gear will have the problem fixed in a minute or two. A great example of this is when the coax jumpers at the top get caught on a leg or similar after wild winds or other mis-rigging that allows them too much slack and they bounce or jump over things they shouldn’t.Also with large antennas on the stack it can’t always come down to the ground because the antennas will hit, so you’ll want to make a wooden X-frame or similar for the tower to rest in when it’s folded down for extended antenona work.For crank over towers many people also retrofit or start them with electric winches with locks. Sized correctly they can save quite a bit of huffing and puffing cranking on a handle to go down or up.What kind of tower segments are they? There’s a lot of people successfully using light tower like Rohn 25 or equivalent but I’m not a fan. We have too much wind here. I prefer 45 or 55 sizes when I can get them.Oh. Anchors and guy wire. The other main thing to look at in where to erect the tower. I assume you need them and this isn’t a free-standing tower. Make sure you have the radii figured out and where the proper anchors can go on the property.

author: SeanB
author_rank: Super Contributor
timestamp: April 02, 2018, 06:40:15 pm
content: A reminder on climbing gear is that it too also has a defined lifetime, and the 10 year expiry date is really not something to base your life on. Old worn out strapping still acting as a safe arrestor and safely ripping the frangible sewing to give you a gentle stop, as opposed to the ripping of the web meaning you plummet down almost unchecked, or you break your back in the stop as the frangible link was too weak to actually absorb the energy.

author: W9GFO
author_rank: Regular Contributor
timestamp: April 02, 2018, 08:04:51 pm
content: Quote from: denverpilot on April 02, 2018, 07:52:49 amThe tower is a Tri-ex (now Tashjian) WT-51. Three section telescopic crank-up, it is self supporting and I also have the tilt over accessory. There would have to be a life and death reason for me to climb that with it cranked up - I can't imagine what that reason would be. If it needs my attention it will have to wait for me to crank it down to 21ft, then I'll climb it - or tilt it over if it is worth the extra trouble.

author: denverpilot
author_rank: Regular Contributor
timestamp: April 02, 2018, 08:44:19 pm
content: Quote from: W9GFO on April 02, 2018, 08:04:51 pmI missed that it was also a crank up besides a fold over. But have seen crank ups get stuck and lots of people climb crank ups when coax systems get hung up on the way up and down.Feedline considerations for engineering purposes are always more compex on movable towers. And you won’t typically be able to utilize hardline on the tower itself in your RF design.Never seen a tower that didn’t have to be climbed yet. Crank up, fold over, stick. Someone has to go up all of them eventually. Highly recommended if climbing a crank up that it be blocked physically through the tower sections as the climber ascends. They have a nasty tendency to collapse if not maintained properly in a straight down fashion and the climber injured severely or killed when they do.When all the mechanical bits are working, they’re a nice compromise to a stick tower. When stuff jams or doesn’t work correctly they can be hyper-dangerous for the worker who has to climb up and fix them.If your plan is never to climb it ever, budget for a professional tower crew when certain problems occur. And stick to manufacturer recommendations for installation and maintenance.I’m planning a tower on my property that folds at approximately the halfway point. It’s what was available locally when someone else took it down. It was up without being folded for approximately a decade and was climbed fairly regularly for silly problems like coax wrapping around things it shouldn’t have at the top in the rotating section, and minor antenna work or coax replacement. Much more than it was folded over. The previous owner said the fold over safety pins were probably only removed to allow it to fold (climbing required to pull those) three times in the decade it stood at its former location.Obviously a crank up has some ability to avoid some of that, but has more opportunities for coax to loop up and get sucked into tower sections as the tower goes up and down if the coax management system isn’t engineered properly. Many pro climbers truly hate crank ups because they’re always called to climb a rickety poorly maintained one and need to block it prior to putting weight on cable based systems not designed to hold the weight of a climber, in order to work on them.Your addition of the ability to fold it over could alleviate that, as long as you leave enough room to fold it over in the fully extended position, which usually stresses them and could lead to a failure also. But at least nobody would be on it or under it if it fell.The more a tower can move, the more thought goes into dealing with problems on it. Sticks, once erected and guyed, don’t have any moving parts. And can be erected very safely with cranes.But when it comes to non-commercial towers with no budget, I’ve seen some rather impressive solutions to erecting and removing them over the years.Be careful, whatever you do. Never any sense in being permanently injured or dead for a hobby. Have fun.