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#1
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So, a mechanical question this time -
On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? The wire itself is light, but the counterweight needs to account for tension as well. The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce |
#2
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On 2/11/11 13:22 , bpnjensen wrote:
So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? The wire itself is light, but the counterweight needs to account for tension as well. The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce Weigh the wire. The counterweight will find a balance with the weight of the wire, allowing an amount of sag equal to the length of the counterweight support. Doubling the counterweight will halve the amount of sag. Redoubling will halve the sag, again. Don't exceed the tensile strength of the wire and start with about 4 times the weight of the wire. |
#3
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On 02/11/2011 11:22 AM, bpnjensen wrote:
So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? The wire itself is light, but the counterweight needs to account for tension as well. The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce Gallon jug of water |
#4
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On Feb 11, 2:11*pm, dave wrote:
On 02/11/2011 11:22 AM, bpnjensen wrote: So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? *The wire itself is light, but the counterweight needs to account for tension as well. *The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. *For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce Gallon jug of water Dave that's a good handy and free starting point. Except if you Live where the Water might Freeze {Oops!} -and- You may be getting Snow and Ice on your Antenna Wire and Loading it down down down,,, Old Plastic Bleach Bottle the Kind with a Handle built into it. Fill the Bottle with about 3~5~10+ Pounds of Small Rocks {or Gravel}. Place the Cap back-on the Bottle and and Tie your Antenna Tension Rope End to the Handle of the Bottle. * Option Tape the Handle of the Bottle with Duck Tape to Reinforce it if needed. * Option Spray Paint the Bottle Green Brown to blend in with the surroundings if needed. -service- These Bottles usually last about 3-Years. -Safety- Use a 5~6 Foot Step Ladder and Position the Bottle at around7~8 Feet or more above Ground so that it is not a Head Injury Hazard. -Rigging- Use a small Pulley to Rig the Tension Rope End through so that the natural dynamic movement of the Antenna Wire and the Counter-Weight Bottle can occur as it happens due to Weather. http://g8jnj.webs.com/Multi%20antenn...igs%28s%29.gif BpnJ - Since you live in the SF Bay go to a Fishing 'Bait' Shop and buy a few Salmon / Down Rigger Weights {3~5 Pound Lead Balls} http://s.ecrater.com/stores/118075/4...4a_118075n.jpg http://cdn.sella.co.nz/images/thumb/...0j-640x500.jpg |
#5
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On Feb 11, 12:16*pm, "D. Peter Maus" wrote:
On 2/11/11 13:22 , bpnjensen wrote: So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? *The wire itself is light, but the counterweight needs to account for tension as well. *The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. *For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce * *Weigh the wire. The counterweight will find a balance with the weight of the wire, allowing an amount of sag equal to the length of the counterweight support. Doubling the counterweight will halve the amount of sag. Redoubling will halve the sag, again. Don't exceed the tensile strength of the wire and start with about 4 times the weight of the wire. Well, the wire's already up there - but I don't think the whole roll weighed but a couple pounds, and this is about 2/3 of the roll in the air (maybe 65 horz feet). So, maybe something like 8 pounds will be a good starting point. Water in any mass doesn't really freeze here (at most we get thin ice on the birdbath, and then only about 5 or 6 times a winter), so that gallon jug of water would be a good starting weight - IIRC, the tensile strength of 14 gauge wire is pretty high, over 100 lbs - isn't that right? So any reasonable weight (like less than 20) is not liable to break it. Good ideas, Peter and Roy and Dave - thanks. |
#6
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On 02/11/2011 03:52 PM, RHF wrote:
.. -service- These Bottles usually last about 3-Years. -Safety- Use a 5~6 Foot Step Ladder and Position the Bottle at around7~8 Feet or more above Ground so that it is not a Head Injury Hazard. So you want the bottle full of rocks so when the UV dissolves it the rocks fall on people? How about a glass jug on UV treated Dacron antenna rope? . |
#7
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On Feb 11, 6:11*pm, dave wrote:
On 02/11/2011 03:52 PM, RHF wrote: . - - -service- These Bottles usually last about 3-Years. - - -Safety- Use a 5~6 Foot Step Ladder and Position - - the Bottle at around7~8 Feet or more above Ground - - so that it is not a Head Injury Hazard. - So you want the bottle full of rocks so when the - UV dissolves it the rocks fall on people? Dave -which-part-of- "-service- These Bottles usually last about 3-Years." - How about a glass jug on UV treated Dacron - antenna rope? Dave : ? "Glass Jug" ? Neighbor's Kid with a Pellet Gun |
#8
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On 2/11/2011 2:22 PM, bpnjensen wrote:
So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? The wire itself is light, but the counterweight needs to account for tension as well. The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce Let me point you in a different direction... When you ask about a weight, that implies you will also be using a pulley (block, for you sailors). This is another piece to purchase and another piece to rust up and fail, at least the hardware store galvanized ones. Don't ask what the ones for sailboats cost. I have had a 130 foot dipole (stranded 14 ga.) up between two trees since 1994, with no failures here in the great Midwest (lots o' wind, lots o' snow). I considered the weight/pulley arrangement but ultimately decided on using a screen door spring at each end. These are typically a foot (or a little more) long and readily available at any hardware store. I would recommend you pay a buck or two more and get the ones that are chrome plated and then spray paint it too, for a little additional weatherproofing (belt AND suspenders). Works fine, lasts a long time. |
#9
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On Feb 12, 6:38*am, Joe from Kokomo wrote:
On 2/11/2011 2:22 PM, bpnjensen wrote: So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? *The wire itself is light, but the counterweight needs to account for tension as well. *The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. *For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce Let me point you in a different direction... When you ask about a weight, that implies you will also be using a pulley (block, for you sailors). This is another piece to purchase and another piece to rust up and fail, at least the hardware store galvanized ones. Don't ask what the ones for sailboats cost. I have had a 130 foot dipole (stranded 14 ga.) up between two trees since 1994, with no failures here in the great Midwest (lots o' wind, lots o' snow). I considered the weight/pulley arrangement but ultimately decided on using a screen door spring at each end. These are typically *a foot (or a little more) long and readily available at any hardware store. I would recommend you pay a buck or two more and get the ones that are chrome plated and then spray paint it too, for a little additional weatherproofing (belt AND suspenders). Works fine, lasts a long time. Hi, Joe- I have thought about a spring - those screen door springs provide enough tension and travel? I expect up to about 3 feet travel on that tree in the highest winds we get here. To be honest, a counterweight is not a problem as to position and safety. A spring might be a little bit neater if it has enough strength and give. Neither one sounds very expensive. Thanks, Bruce |
#10
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On Feb 13, 8:56*am, bpnjensen wrote:
On Feb 13, 4:03*am, RHF wrote: On Feb 12, 10:03*pm, bpnjensen wrote: On Feb 12, 6:38*am, Joe from Kokomo wrote: On 2/11/2011 2:22 PM, bpnjensen wrote: So, a mechanical question this time - On a relatively short run of wire of fairly light weight (in this case, 14 gauge stranded, insulated, and about 60-65 feet horizontal), what's a good estimated counterweight for the far end? *The wire itself is light, but the counterweight needs to account for tension as well. *The support line is over a freewheeling pulley and is currently tied off, but I think a modest eight would be better in this circumstance as the near end of the line is a treetop with some sway in the wind. So, I ask if anybody has an idea about what a good weight night be to maintain tension and avoid too much sagging. *For starters, I was thinking a simple barbell weight of 5 lbs or so more or less, but I'm wide open on this one. Thanks so much! Bruce Let me point you in a different direction... When you ask about a weight, that implies you will also be using a pulley (block, for you sailors). This is another piece to purchase and another piece to rust up and fail, at least the hardware store galvanized ones. Don't ask what the ones for sailboats cost. I have had a 130 foot dipole (stranded 14 ga.) up between two trees since 1994, with no failures here in the great Midwest (lots o' wind, lots o' snow). I considered the weight/pulley arrangement but ultimately decided on using a screen door spring at each end. These are typically *a foot (or a little more) long and readily available at any hardware store. I would recommend you pay a buck or two more and get the ones that are chrome plated and then spray paint it too, for a little additional weatherproofing (belt AND suspenders). Works fine, lasts a long time. Hi, Joe- I have thought about a spring - those screen door springs provide enough tension and travel? I expect up to about 3 feet travel on that tree in the highest winds we get here. To be honest, a counterweight is not a problem as to position and safety. *A spring might be a little bit neater if it has enough strength and give. *Neither one sounds very expensive. Thanks, Bruce OSH Hardware* has Good Quality Chromed Pulleys with Brass Roller; Poly & Nylon Rope and a fair selection of Zinc Plated Springs of all Diameters, Lengths and Gauges. ~ RHF Pulley : Chrome-Plated Zinc Die-Cast Housing and Swivel Eyehttp://www.fdsons.com/popup_image.php?pID=19638http://www.acehardware... * ACE, *Home Depot and Lowe's too. *. - OSH is my store, not the least of which because - they have great free train calendars :-) Free Train Calendars :-) ![]() ![]() ![]() ![]() |
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