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Using speaker wire for a dipole
Anyone have experience making a dipole from 18 gauge speaker wire? I
have a whole lot of it lying around the house, and was wondering if I could put it to some good use. |
Using speaker wire for a dipole
|
Using speaker wire for a dipole
On 7/31/2011 4:02 PM, Owen Duffy wrote:
Owen PS: hams universally ignore the guidance of NFPA 70 which makes recommendation on conductors for antennas. Maybe because NFPA 70 costs $150 US? John |
Using speaker wire for a dipole
John S wrote in :
Maybe because NFPA 70 costs $150 US? Yes, standards are expensive things and it is a frustration when researching. Anyway, NFPA makes recommendation on the wires for ham antennas specifically, and it may be binding in some places. I suspect the reason for ignoring it is that the advice is unaccepable to most hams. That said, it does seem over the top in some areas, and is hardly comprehensive in its thinking. For example, the prescription for feedlines seems to not be aware of the existence and use of coax. I guess it is these gaps that give critics the basis for arguing against the whole thing. Anyway, in respect of antenna wires, it does not 'permit' annealled copper or other low strength materials, and it 'requires' a minimum conductor diameter of #14 for up to 150' span. They may have had in mind the risk to persons and property where low strength conductor are broken in high wind and make contact with power lines. Owen |
Using speaker wire for a dipole
"KD2AIP" wrote in message ... Anyone have experience making a dipole from 18 gauge speaker wire? I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. - Should work fine with the caveats of added weight from the insulation, etc. Some years ago, there was a QST article written by a ham who built a 20 meter quad using insulated wire. He found that it changed the expected resonance, IIRC downward. So you may have to play with the length a little more than expected from the calculated lengths. |
Using speaker wire for a dipole
This topic is likely to spur a lot of discussion. For a while two of us
were using zip cord which in itself is frequently used as speaker wire. Mine was strung across and somewhat around the back yard to I could work 75m and up with a tuner. George, VE6VA surprised me when I noticed he had a feedling going out of his shack -- it was cloth covered line cord! Both of us had lots of fun on the bands. I should add that my transmission line and both halves of the dipole were made from one piece of line cord/speaker wire -- I just brought the end of the transmission line into a plastic wire-tie, and fed the lines around the yard, using a couple tree branches and a small pole on the garage. The other dipole half was just long enough to reach the front of the house where it was then suspended by a small lilac bush and a tall fir tree. End insulators were just bits of scrap plastic and both ends were suspended with a long string of short and medium pieces tied together! From experience I think that I can generalize that you matter how much nylon line a ham buys, in time it degenerates into a wide assortment of randomly short lengths, none of which alone can serve any purpose! After 50 plus years of hamming fun, I have come to the conclusion that anything with a little metal in it will serve as an antenna if you hook it up in the right manner. It has truly surprised me over the years just how little antenna I had, and how far it was getting out. Some antenna's will work better than others, and eventually every ham, whose expectations eventually approch infinity will want to try a 'better antenna'. Aside from collecting materials, and it doesn't take much to make a dipole, once you know where you can string your wires, it's easy to try a variety of antennas. In the long run you will probably find that a half wave dipole will do the best, and if you can drop the ends, changing it into an inverted-Vee you will have near omnidirectional operation on the higher bands. Antennas, discussed here have impedance, Jx+something or other, specific lengths, and so many rules that your life as a ham will make you miserable when you dare approach the shack. Throw an arrow into the air (throw an antenna into the air), suspend it here and there, and then see if it works. If it does, Great! -- If it doesn't -- well, try something else. Chances are you will have so much fun that you postpone tidying up the knots, but some of those things stay up for ever until their age approaches that of a typical old fogie antenna fussy, Smith chart interpreter, know-it- all hams, like most of us here Antennas are funny people! Get the wire up, have a ball! Irv VE6BP, Calgary Political correctness is a doctrine, fostered by a delusional, illogical minority, and rapidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a piece of poop by the clean end. "KD2AIP" wrote in message ... Anyone have experience making a dipole from 18 gauge speaker wire? I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. |
Using speaker wire for a dipole
"KD2AIP" wrote in message ... Anyone have experience making a dipole from 18 gauge speaker wire? I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. My favored gauges are 12 and 14. I took a dipole I modeled in EZNEC (Evaluation Version) and changed from 12 gauge to 18 gauge. The behavior of the antenna changed dramatically. No, I'm kidding. EZNEC showed insignificant shifts in VSWR and gain at optimum takeoff angle. You apparently face only mechanical issues. If the wire parts when you pull it up, you'll need to connect it to a stout span line. I have two 20m dipoles hanging, one with a span line and one free-hanging. They were both temporary ... last year. "Sal" Champion Procrastinator |
Using speaker wire for a dipole
"Irv Finkleman" wrote in
: .... I should add that my transmission line and both halves of the dipole were made from one piece of line cord/speaker wire Yes, I freely admit that I was a sucker who implemented that type of antenna system on the advice of mentors. Since learning those j thingies that you deride, I have come to learn enough to quantify the sacrifice in performance. Yes, it 'works', whatever that means! One way to make sure newbies never challenge you is to lead them down the same misdirected paths as yourself in the hope that they never catch up. Whilst there are those who glibly recite that "any antenna is better than no antenna at all", it is also true that you might work stations on any antenna, just you will work more on a better antenna. I know that dumbing down the hobby is the fashionable trend, deride those who see ham radio as an essentially techical exploit as the new age ham is embarking on a social experience, just the connectivity is several orders of magnitude below those of most social network appliances. Whilst cutting edge hams are breaking DX records with things like WSPR at 0.5bps, kids are socialising on mobile phones at greater than 10Mbps. When you take the passion for understanding the technology out of ham radio, it just doesn't compete. Owen |
Using speaker wire for a dipole
"Sal" wrote in :
I have two 20m dipoles hanging, one with a span line and one free-hanging. They were both temporary ... last year. Sal, there would be those who would chide you that such an antenna obviously wasn't big enough... in the sense that "if it didn't blow down last season, it wasn't big enough". And we wonder why so many housing block have restictive covenants that are not ham friendly. We might just have bought that on ourselves to some extent. Owen |
Using speaker wire for a dipole
On 7/31/2011 2:02 PM, Owen Duffy wrote:
PS: hams universally ignore the guidance of NFPA 70 which makes recommendation on conductors for antennas. Are you saying the electrical code is sort of like the pirate code? more guidelines than actual requirements? I think the way that hams can rationalize it is that most wire antennas (particularly those made with fine wire) are, by their nature, "temporary installations". The finer the wire, the more temporary. |
Using speaker wire for a dipole
On 7/31/2011 3:09 PM, John S wrote:
On 7/31/2011 4:02 PM, Owen Duffy wrote: Owen PS: hams universally ignore the guidance of NFPA 70 which makes recommendation on conductors for antennas. Maybe because NFPA 70 costs $150 US? John Free at the library, and at various sites for California Title 24. http://rrdocs.nfpa.org/rrserver/brow...tricalCode2010 And the sections on antennas are widely quoted. I don't think cost of a copy of the code is why hams don't follow it. here you go: II Receiving Equipment - Antenna Systems Article 810.16 Size of Wire-Strung Antenna -Receiving Station (A) Size of Antenna Conductors. Outdoor antenna conductors for receiving stations shall be of a size not less than given in Table 810.16(A) Table 810.16(A) Size of Receiving Station Outdoor Antenna Conductors Minimum size of Conductors (AWG) where Maximum Open Span Length is: Less than 11m 11m to 45m Over 45m Al Alloy, hard drawn copper 19 14 12 Cu Clad Steel, Bronze, other high strength matl 20 17 14 Or III Amateur Transmitting and Receiving Stations - Antenna Systems less than 45 m over 45 m Hard drawn copper AWG 14 AWG 10 CCS, bronze, etc. AWG 14 AWG 12 |
Using speaker wire for a dipole
On 7/31/2011 3:26 PM, Owen Duffy wrote:
John wrote in : Maybe because NFPA 70 costs $150 US? Yes, standards are expensive things and it is a frustration when researching. Anyway, NFPA makes recommendation on the wires for ham antennas specifically, and it may be binding in some places. I suspect the reason for ignoring it is that the advice is unaccepable to most hams. That said, it does seem over the top in some areas, and is hardly comprehensive in its thinking. For example, the prescription for feedlines seems to not be aware of the existence and use of coax. You refer to the "continuously enclosed metallic shield", I suspect. I guess it is these gaps that give critics the basis for arguing against the whole thing. Anyway, in respect of antenna wires, it does not 'permit' annealled copper or other low strength materials, and it 'requires' a minimum conductor diameter of #14 for up to 150' span. They may have had in mind the risk to persons and property where low strength conductor are broken in high wind and make contact with power lines. That is precisely why. (ice loads, too) |
Using speaker wire for a dipole
Jim Lux wrote in
: .... III Amateur Transmitting and Receiving Stations - Antenna Systems less than 45 m over 45 m Hard drawn copper AWG 14 AWG 10 CCS, bronze, etc. AWG 14 AWG 12 Examples 7 and 8 in the catenary calculator at http://vk1od.net/calc/awcc/awcc.htm use #14 and #10 HDC. Readers can explore the survivability of wind and ice with the calculator. If I model a 45m simple span of #14 HDC at the lowest wind speeds applicable to the design of structures in this jurisdiction, using the mandated safety factor, the minimum sag is about 5% of span, about as large as it typically practical for such a span. NFPA 70 does not apply in VK, though there are standards that apply and the answer comes up pretty much the same, just there is more freedom in engineering shorter spans. Owen |
Using speaker wire for a dipole
Stainless steel mig welding wire.
Any reason why this won't work as a wire antenna? Very strong, fairly cheap, but doesn't like kinks. 'I personally think Ray Davies wrote some very good songs.' http://en.wikipedia.org/wiki/Ray_Davies |
Using speaker wire for a dipole
wrote in :
Stainless steel mig welding wire. Any reason why this won't work as a wire antenna? Very strong, fairly cheap, but doesn't like kinks. It is small diameter, high resistivity material. If it is magnetic, even worse. I depends on its length, and the current flowing. The article http://vk1od.net/antenna/conductors/loss.htm includes an example of 316 SS MIG wire. It is great for stealth antennas, actually doubly so, because not only is it hard to see, it is hard to hear. Owen |
Using speaker wire for a dipole
On 1 Aug,
Owen Duffy wrote: "Sal" wrote in : I have two 20m dipoles hanging, one with a span line and one free-hanging. They were both temporary ... last year. Sal, there would be those who would chide you that such an antenna obviously wasn't big enough... in the sense that "if it didn't blow down last season, it wasn't big enough". And we wonder why so many housing block have restictive covenants that are not ham friendly. We might just have bought that on ourselves to some extent. At one time I was working JA from yhe UK using a long wire (about 40m) of 30 swg and 100w. It didn't blow down. however it was only up for a week as a stealth ant. currently my long wire is 1mm enameled wire, to be less vu=isibly intrusive (and at current copper prices cheaper) than the recommended 14 swg (12 awg). This replaces one which failed a couple of years ago constructed with thin insulated 5A lighting flex not much more than bell wire that had been up nearly 30 years. It's better using a non optimal stealth ant than none at all! -- BD Change lycos to yahoo to reply |
Using speaker wire for a dipole
On 8/1/2011 7:52 PM, Jim Lux wrote:
On 7/31/2011 3:26 PM, Owen Duffy wrote: John wrote in : Maybe because NFPA 70 costs $150 US? Yes, standards are expensive things and it is a frustration when researching. Anyway, NFPA makes recommendation on the wires for ham antennas specifically, and it may be binding in some places. I suspect the reason for ignoring it is that the advice is unaccepable to most hams. That said, it does seem over the top in some areas, and is hardly comprehensive in its thinking. For example, the prescription for feedlines seems to not be aware of the existence and use of coax. You refer to the "continuously enclosed metallic shield", I suspect. I guess it is these gaps that give critics the basis for arguing against the whole thing. Anyway, in respect of antenna wires, it does not 'permit' annealled copper or other low strength materials, and it 'requires' a minimum conductor diameter of #14 for up to 150' span. They may have had in mind the risk to persons and property where low strength conductor are broken in high wind and make contact with power lines. That is precisely why. (ice loads, too) NFPA (according to what you posted) requires heavier gauge wire for transmitting than for receiving. Transmitting makes the wire weigh more? |
Using speaker wire for a dipole
"Owen Duffy" wrote in message ... "Sal" wrote in : I have two 20m dipoles hanging, one with a span line and one free-hanging. They were both temporary ... last year. Sal, there would be those who would chide you that such an antenna obviously wasn't big enough... in the sense that "if it didn't blow down last season, it wasn't big enough". LOL And we wonder why so many housing block have restictive covenants that are not ham friendly. We might just have bought that on ourselves to some extent. I'm in a 1960s neighborhood. If anybody bitches about antennas (nothing, yet), I will invite their attention to the old-fashioned utility poles & wires that decorate (?) the streets. A few blocks out and a few years later, they undergrounded the utilities. Sal |
Using speaker wire for a dipole
wrote in message ... On 1 Aug, This replaces one which failed a couple of years ago constructed with thin insulated 5A lighting flex not much more than bell wire that had been up nearly 30 years. This got me thinking. (Dangerous, yes, but I occasionally risk it.) Since a normal dipole has current max near the center, is there more localized heating (I-squared-R) nearer the feed point? Seems like it ought to be. Can you overheat a small wire and make it fail there by melting????? No, I don't want to try it. I'm hoping somebody knows. Exciting story even better. "Sal" |
Using speaker wire for a dipole
On 7/31/2011 16:32, KD2AIP wrote:
Anyone have experience making a dipole from 18 gauge speaker wire? I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. Be aware that the National Electric Code (NEC); that is enforced as law in many jurisdictions; forbids the use of wire that small for aerials of radio stations. The NEC specifically requires that size fourteen American Wire Gauge be the minimum size that is used. In point of fact you are unlikely to ever get inspected unless some neighbor is raising a stink about your antenna. The danger is that in the event of a physical failure of the antenna that brings harm to anyone or anything, the use of non code compliant size wire will shift all blame on to you. That could include a trespassing neighbor kid yanking on your coax lead in and being burned before you realized that the antenna was in direct contact with him because the wire of the antenna that was supporting the coax had failed. The reason that you might be blamed for something that at first blush appears to be outrageous conduct on the kids part is based on the idea that anything like that which is not sufficiently guarded so as to prevent that kind of occurrence is considered to be an attractive nuisance in the eyes of the law. If the wire is supported on a messenger that has at least the breaking strength of #14 AWG wire the reasonableness standard should serve as an effective shield against that particular approach in a law suit. Be aware that in electrical parlance, which is what the code is written in, messenger supported means that it is continuously supported by another means. It does not mean that it is suspended from some stronger support at it's ends. To be messenger supported the entire weight and the catenary strain of the support system would have to be born entirely by a means other than the undersized conductor itself. I am not a lawyer nor do I play one on local cable access television. If you need advice about the most likely legal affects of an injury that is caused by your amateur radio equipment you might want to patronize a law schools legal clinic. The Professors that supervise such clinics love questions like this because they take a fair amount of effort to answer well. What you end up with is really high quality advice prepared under the supervision of some of the best legal minds that a person of ordinary means could ever get access to. I've quoted the sections of the NEC which are applicable to antenna conductor size below. Be aware that the NEC contains many more provisions covering amateur radio stations specifically. It is worth your time to obtain the use of the edition of the NEC that is adopted for enforcement in your community and check your installation against the provisions of the code. -- FWIW YMMV Tom Horne, W3TDH "ARTICLE 810 Radio and Television Equipment I. General 810.1 Scope. This article covers antenna systems for radio and television receiving equipment, amateur radio transmitting and receiving equipment, and certain features of transmitter safety. This article covers antennas such as multi-element, vertical rod, and dish, and also covers the wiring and cabling that connects them to equipment. 810.11 Material. Antennas and lead-in conductors shall be of hard-drawn copper, bronze, aluminum alloy, copper-clad steel, or other high-strength, corrosion-resistant material. Exception: Soft-drawn or medium-drawn copper shall be permitted for lead-in conductors where the maximum span between points of support is less than 11 m (35 ft). 810.12 Supports. Outdoor antennas and lead-in conductors shall be securely supported. The antennas or lead-in conductors shall not be attached to the electric service mast. They shall not be attached to poles or similar structures carrying open electric light or power wires or trolley wires of over 250 volts between conductors. Insulators supporting the antenna conductors shall have sufficient mechanical strength to safely support the conductors. Lead-in conductors shall be securely attached to the antennas. 810.13 Avoidance of Contacts with Conductors of Other Systems. Outdoor antennas and lead-in conductors from an antenna to a building shall not cross over open conductors of electric light or power circuits and shall be kept well away from all such circuits so as to avoid the possibility of accidental contact. Where proximity to open electric light or power service conductors of less than 250 volts between conductors cannot be avoided, the installation shall be such as to provide a clearance of at least 600 mm (2 ft). Where practicable, antenna conductors shall be installed so as not to cross under open electric light or power conductors. [One of the leading causes of electrical shock and electrocution, according to statistical reports, is the accidental contact of radio, television, and amateur radio transmitting and receiving antennas and equipment with light or power conductors. Extreme caution should therefore be exercised during this type of installation, and periodic visual inspections should be conducted thereafter. ] This is explanatory material from the NEC Handbook and not part of the NEC. 810.14 Splices. Splices and joints in antenna spans shall be made mechanically secure with approved splicing devices or by such other means as will not appreciably weaken the conductors. [Conductor spans from antennas should be of sufficient size and strength to maintain clearances and avoid possible contact with light or power conductors. Splices and joints should be made with approved connectors or other means that provide sufficient mechanical strength so that conductors are not weakened appreciably, a condition that could cause them to break and come into contact with higher-voltage conductors.] This is explanatory material from the NEC Handbook and not part of the NEC. 810.15 Grounding. Masts and metal structures supporting antennas shall be grounded in accordance with 810.21. 810.52 Size of Antenna. Antenna conductors for transmitting and receiving stations shall be of a size not less than given in Table 810.52. Table 810.52 Size of Amateur Station Outdoor Antenna Conductors Material Minimum Size of Conductors (AWG) Where Maximum Open Span Length Is Less Than 45 m (150 ft) Over 45 m (150 ft) Hard-drawn copper 14 10 Copper-clad steel, bronze, or other high-strength material 14 12 810.53 Size of Lead-In Conductors. Lead-in conductors for transmitting stations shall, for various maximum span lengths, be of a size at least as great as that of conductors for antennas as specified in 810.52." Copyright 2002 the National Fire Protection Association. |
Using speaker wire for a dipole
On 8/2/2011 11:24, John S wrote:
On 8/1/2011 7:52 PM, Jim Lux wrote: On 7/31/2011 3:26 PM, Owen Duffy wrote: John wrote in : Maybe because NFPA 70 costs $150 US? Yes, standards are expensive things and it is a frustration when researching. Anyway, NFPA makes recommendation on the wires for ham antennas specifically, and it may be binding in some places. I suspect the reason for ignoring it is that the advice is unaccepable to most hams. That said, it does seem over the top in some areas, and is hardly comprehensive in its thinking. For example, the prescription for feedlines seems to not be aware of the existence and use of coax. You refer to the "continuously enclosed metallic shield", I suspect. I guess it is these gaps that give critics the basis for arguing against the whole thing. Anyway, in respect of antenna wires, it does not 'permit' annealled copper or other low strength materials, and it 'requires' a minimum conductor diameter of #14 for up to 150' span. They may have had in mind the risk to persons and property where low strength conductor are broken in high wind and make contact with power lines. That is precisely why. (ice loads, too) NFPA (according to what you posted) requires heavier gauge wire for transmitting than for receiving. Transmitting makes the wire weigh more? No but it does make it more dangerous to persons and things on which it might fall if it breaks. -- Tom Horne, W3TDH |
Using speaker wire for a dipole
On Tue, 2 Aug 2011 12:24:10 -0700, "Sal" wrote:
This got me thinking. (Dangerous, yes, but I occasionally risk it.) It is supposed to be a license requirment. Since a normal dipole has current max near the center, is there more localized heating (I-squared-R) nearer the feed point? Seems like it ought to be. Can you overheat a small wire and make it fail there by melting????? Yup. The amount of current that would do that is called the "Fuse Current" which can be dramatically large. Example, wirewrap wire's fuse current is slightly more than 10 Amps. 73's Richard Clark, KB7QHC |
Using speaker wire for a dipole
On 8/1/2011 20:42, Jim Lux wrote:
On 7/31/2011 2:02 PM, Owen Duffy wrote: PS: hams universally ignore the guidance of NFPA 70 which makes recommendation on conductors for antennas. Are you saying the electrical code is sort of like the pirate code? more guidelines than actual requirements? I think the way that hams can rationalize it is that most wire antennas (particularly those made with fine wire) are, by their nature, "temporary installations". The finer the wire, the more temporary. The National Electric Code limits the use of Temporary installations to power and lighting conductors. "ARTICLE 527 Temporary Installations 527.1 Scope. The provisions of this article apply to temporary electrical power and lighting installations." Copyright 2002 the National Fire Protection Association. -- Tom Horne, W3TDH |
Using speaker wire for a dipole
On 7/31/2011 23:51, Irv Finkleman wrote:
This topic is likely to spur a lot of discussion. For a while two of us were using zip cord which in itself is frequently used as speaker wire. Mine was strung across and somewhat around the back yard to I could work 75m and up with a tuner. George, VE6VA surprised me when I noticed he had a feedling going out of his shack -- it was cloth covered line cord! Both of us had lots of fun on the bands. I should add that my transmission line and both halves of the dipole were made from one piece of line cord/speaker wire -- I just brought the end of the transmission line into a plastic wire-tie, and fed the lines around the yard, using a couple tree branches and a small pole on the garage. The other dipole half was just long enough to reach the front of the house where it was then suspended by a small lilac bush and a tall fir tree. End insulators were just bits of scrap plastic and both ends were suspended with a long string of short and medium pieces tied together! From experience I think that I can generalize that you matter how much nylon line a ham buys, in time it degenerates into a wide assortment of randomly short lengths, none of which alone can serve any purpose! After 50 plus years of hamming fun, I have come to the conclusion that anything with a little metal in it will serve as an antenna if you hook it up in the right manner. It has truly surprised me over the years just how little antenna I had, and how far it was getting out. Some antenna's will work better than others, and eventually every ham, whose expectations eventually approch infinity will want to try a 'better antenna'. Aside from collecting materials, and it doesn't take much to make a dipole, once you know where you can string your wires, it's easy to try a variety of antennas. In the long run you will probably find that a half wave dipole will do the best, and if you can drop the ends, changing it into an inverted-Vee you will have near omnidirectional operation on the higher bands. Antennas, discussed here have impedance, Jx+something or other, specific lengths, and so many rules that your life as a ham will make you miserable when you dare approach the shack. Throw an arrow into the air (throw an antenna into the air), suspend it here and there, and then see if it works. If it does, Great! -- If it doesn't -- well, try something else. Chances are you will have so much fun that you postpone tidying up the knots, but some of those things stay up for ever until their age approaches that of a typical old fogie antenna fussy, Smith chart interpreter, know-it- all hams, like most of us here Antennas are funny people! Get the wire up, have a ball! Irv VE6BP, Calgary Political correctness is a doctrine, fostered by a delusional, illogical minority, and rapidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a piece of poop by the clean end. "KD2AIP" wrote in message ... Anyone have experience making a dipole from 18 gauge speaker wire? I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. Because it disrupts the normal flow of the conversation. Why is top posting on use net considered discourteous? -- Tom Horne, W3TDH |
Using speaker wire for a dipole
"Tom Horne" wrote in message ... On 7/31/2011 16:32, KD2AIP wrote: Anyone have experience making a dipole from 18 gauge speaker wire? I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. Be aware that the National Electric Code (NEC); that is enforced as law in many jurisdictions; forbids the use of wire that small for aerials of radio stations. The NEC specifically requires that size fourteen American Wire Gauge be the minimum size that is used. snip - And of course, there are hams out there who consider the NEC, as applied to antennas on their own property, to be an irrelevant government overreach. Naturally, that is not my opinion :) |
Using speaker wire for a dipole
On 8/2/2011 7:33 PM, Tom Horne wrote:
No but it does make it more dangerous to persons and things on which it might fall if it breaks. Come on, Guys! While it's a great idea to follow every official code and reccomendation, and that no one in their "right mind" would ever consider anything less than the lowest gauge copperweld wire for their antenna, the original question is answerable by "Yes, you can make a serviceable antenna out of speaker wire." Will it stay up as long as a Copperweld antenna held in place by1/4 inch thick 100 percent nylon rope? No it won't. But it will work. Surprisingly well, in fact. Let the new guys learn, and throw up antennas that work. As they have to put up a new one every so often, they will eventually learn about more long lasting antennas, as well as ones that might have a better pattern, and other effects that bear on performance. But the idea that hams are responsible for restrictive covenents (in reality, Cable television is more responsible for antenna covenants than anything else) or that the choice of speaker wire is going to electrocute the neighbors is doing a disservice to the new guys and gals. I can say this with some conviction because I was one of those noobs once, and nearly didn't even get on HF because with all the input, I gave up on putting up an antenna because nothing was good enough. I didn't have enough space, I didn't have enough height. There just wasn't any use in getting on the low bands. I needed a separate antenna for every band because ladder line was awful and traps were bad and every other option was awful except for some idealized correct antenna, coax fed, at the proper height. - 73 de Mike N3LI - |
Using speaker wire for a dipole
On 8/2/2011 7:42 PM, Tom Horne wrote:
"ARTICLE 527 Temporary Installations 527.1 Scope. The provisions of this article apply to temporary electrical power and lighting installations." Copyright 2002 the National Fire Protection Association. I have found that the safest option is to not ever put up any antenna whatsoever, Tom. It's just too dangerous, and gives us unneeded exposure. Can you ensure that an antenna that is installed to the code specifications, will not fall down? Will your code spec prevent you from incurring liability if a wire antenna falls down and electrocutes a neighbor? The answer to both questions is "no", BTW. I find that this entire discussion is pretty amazing when compared to the original question. As opposed to electrical code and liability admonitions, perhaps a good answer is: "Yes, you can make an adequate antenna from speaker wire. There might be better options, though." - 73 de Mike N3LI - |
Using speaker wire for a dipole
On Tue, 02 Aug 2011 23:11:33 -0400, Mike Coslo rearranged some electrons
to say: But it will work. Surprisingly well, in fact. My present HF antenna is a piece of 4-conductor ribbon cable, with 60 feet of each outside conductor pulled off to make a 120 foot dipole, the rest of the cable being used as a feedline to a balun and thence to a tuner. Is it ideal? No. But it's good enough to work 45 states so far on 75m, a few dozen DX contacts on 20 and 40m, etc. Plus, it's nearly invisible against the side of the house. During field day, I used a homemade doublet fed with 450 ohm ladder line to the same tuner, remotely mounted in a waterproof box, I was able to work 15m and 80m on the same antenna, made a few hundred contacts. Eventually (when the leaves fall) I plan to replace the ribbon cable dipole with the doublet and the remote tuner on some tall trees in the backyard. |
Using speaker wire for a dipole
Very simply, yes, it can be used for making antennas. If it's strong
enough to hold up it's own weight, and that of the feed line without stretching unreasonably, then it should do fine. What happens if it stretches? You shorten it. I think I'd try a larger size for 160 meters and maybe 80 meters, but if it can stand the weight and the weather, why not? - 'Doc |
Using speaker wire for a dipole
Hear! Hear!
I would have been off the air forever if this newsgroup had been my only source of knowledge. I would have been afraid! What I didn't know about Jx and SWR didn't make any difference -- I was on the air and really enjoying the hobby! I didn't even know how to solder then! Irv VE6BP (first licenced in '58) "Mike Coslo" wrote in message ... On 8/2/2011 7:33 PM, Tom Horne wrote: No but it does make it more dangerous to persons and things on which it might fall if it breaks. Come on, Guys! While it's a great idea to follow every official code and reccomendation, and that no one in their "right mind" would ever consider anything less than the lowest gauge copperweld wire for their antenna, the original question is answerable by "Yes, you can make a serviceable antenna out of speaker wire." Will it stay up as long as a Copperweld antenna held in place by1/4 inch thick 100 percent nylon rope? No it won't. But it will work. Surprisingly well, in fact. Let the new guys learn, and throw up antennas that work. As they have to put up a new one every so often, they will eventually learn about more long lasting antennas, as well as ones that might have a better pattern, and other effects that bear on performance. But the idea that hams are responsible for restrictive covenents (in reality, Cable television is more responsible for antenna covenants than anything else) or that the choice of speaker wire is going to electrocute the neighbors is doing a disservice to the new guys and gals. I can say this with some conviction because I was one of those noobs once, and nearly didn't even get on HF because with all the input, I gave up on putting up an antenna because nothing was good enough. I didn't have enough space, I didn't have enough height. There just wasn't any use in getting on the low bands. I needed a separate antenna for every band because ladder line was awful and traps were bad and every other option was awful except for some idealized correct antenna, coax fed, at the proper height. - 73 de Mike N3LI - |
Using speaker wire for a dipole
On 8/3/2011 4:48 PM, Irv Finkleman wrote:
Hear! Hear! I would have been off the air forever if this newsgroup had been my only source of knowledge. I would have been afraid! What I didn't know about Jx and SWR didn't make any difference -- I was on the air and really enjoying the hobby! I didn't even know how to solder then! Right. But I would like to say that it isn't at all that the information is wrong. In fact, the experts are generally 100 percent right. And that is where some of the problems are. A noob comes in, and gets 3 different answers, and becomes hopelessly confused because they would seem to contradict each other. They don't really know how to figure it out. It isn't confined to this group. Another group I'm in where I am a bit of an expert, Amateur telescope making, some times suffers from the same thing. My point is that I'm not trying to chide the experts. After all, it's not very graceful to bust peoples chops when they take the time to answer a question. I's more begging them to realize that I'm a bit of an idiot, and easily confused! - 73 de Mike N3LI - |
Using speaker wire for a dipole
"Irv Finkleman" wrote in message ... snip After 50 plus years of hamming fun, I have come to the conclusion that anything with a little metal in it will serve as an antenna if you hook it up in the right manner. Yes. I have properly-built 6m jpole which terminates in my shack. If I disconnect the coax from the 6m rig, the connector center pin fits nicely into the LONG WIRE terminal on my HF tuner. Electrically, the antenna is merely a 13' hunk of metal, untuned as far as HF is concerned, except after a little tuner knobulation. It's not the equal of a 'proper" antenna, but it works. |
Using speaker wire for a dipole
On 8/2/2011 8:24 AM, John S wrote:
On 8/1/2011 7:52 PM, Jim Lux wrote: On 7/31/2011 3:26 PM, Owen Duffy wrote: John wrote in : Maybe because NFPA 70 costs $150 US? Yes, standards are expensive things and it is a frustration when researching. Anyway, NFPA makes recommendation on the wires for ham antennas specifically, and it may be binding in some places. I suspect the reason for ignoring it is that the advice is unaccepable to most hams. That said, it does seem over the top in some areas, and is hardly comprehensive in its thinking. For example, the prescription for feedlines seems to not be aware of the existence and use of coax. You refer to the "continuously enclosed metallic shield", I suspect. I guess it is these gaps that give critics the basis for arguing against the whole thing. Anyway, in respect of antenna wires, it does not 'permit' annealled copper or other low strength materials, and it 'requires' a minimum conductor diameter of #14 for up to 150' span. They may have had in mind the risk to persons and property where low strength conductor are broken in high wind and make contact with power lines. That is precisely why. (ice loads, too) NFPA (according to what you posted) requires heavier gauge wire for transmitting than for receiving. Transmitting makes the wire weigh more? An interesting observation. You'd have to go look at the history of that article in the code to find out why. It's not impossible that they were following standard commercial installation practice/recommendations back in the day, and it was "acceptable power loss" related. (the wire sizing for AC branch circuits is based on tolerating a 2% voltage drop, not overheating of the conductor) |
Using speaker wire for a dipole
On 8/2/2011 12:24 PM, Sal wrote:
wrote in message ... On 1 Aug, This replaces one which failed a couple of years ago constructed with thin insulated 5A lighting flex not much more than bell wire that had been up nearly 30 years. This got me thinking. (Dangerous, yes, but I occasionally risk it.) Since a normal dipole has current max near the center, is there more localized heating (I-squared-R) nearer the feed point? Seems like it ought to be. Can you overheat a small wire and make it fail there by melting????? No, I don't want to try it. I'm hoping somebody knows. Exciting story even better. "Sal" Fusing current is remarkably high for small conductors in free air, even for 100% duty cycle. AWG30 (0.01" diameter) = about 10 Amps (Preece equation) Scales as 1.5 power.. so, going to AWG 20 (.0316") - about 50 amps.. Considering an inverted V dipole with feedpoint Z of 50 ohms, at 1kW, the current is about 5 amps... So running that legal limit amp with a brick on the key to your AWG30 stealth antenna won't melt it. (it probably will get pretty warm.. and corona at the ends might be spectacular) |
Using speaker wire for a dipole
On 8/2/2011 4:42 PM, Tom Horne wrote:
On 8/1/2011 20:42, Jim Lux wrote: On 7/31/2011 2:02 PM, Owen Duffy wrote: PS: hams universally ignore the guidance of NFPA 70 which makes recommendation on conductors for antennas. Are you saying the electrical code is sort of like the pirate code? more guidelines than actual requirements? I think the way that hams can rationalize it is that most wire antennas (particularly those made with fine wire) are, by their nature, "temporary installations". The finer the wire, the more temporary. The National Electric Code limits the use of Temporary installations to power and lighting conductors. "ARTICLE 527 Temporary Installations 527.1 Scope. The provisions of this article apply to temporary electrical power and lighting installations." Copyright 2002 the National Fire Protection Association. -- Tom Horne, W3TDH I was thinking more of local codes or enforcement. After all, the local "Authority Having Jurisdiction" (AHJ in code-speak) can and does override the NEC all the time. There are also a whole lot of other "installations of a temporary nature" in the code: check out the sections about theatrical and motion picture filming. They allow substantially higher currents for a given size wire, on the not unreasonable basis that they're being operated under the (hopefully) continuous supervision of qualified personnel. |
Using speaker wire for a dipole
"Jim Lux" wrote in message ... Fusing current is remarkably high for small conductors in free air, even for 100% duty cycle. AWG30 (0.01" diameter) = about 10 Amps (Preece equation) Scales as 1.5 power.. so, going to AWG 20 (.0316") - about 50 amps.. Considering an inverted V dipole with feedpoint Z of 50 ohms, at 1kW, the current is about 5 amps... So running that legal limit amp with a brick on the key to your AWG30 stealth antenna won't melt it. (it probably will get pretty warm.. and corona at the ends might be spectacular) Thank you very much. It's exactly what I was wondering about. "Sal" |
Using speaker wire for a dipole
On Aug 1, 6:32*am, KD2AIP wrote:
Anyone have experience making a dipole from 18 gauge speaker wire? *I have a whole lot of it lying around the house, and was wondering if I could put it to some good use. Well, not sure what gauge wire it is, but I've been using cheap speakerwire for HF dipoles with no problems whatsoever. Not certain, but I think this is the stuff I use he http://www.jaycar.com.au/productView...SUBCATID=992#1 My prime HF antenna started out as a coax-fed 40m half-wave (10m/leg) dipole made of this stuff in an inverted-V configuration. I used a home made 1:1 voltage balun at the feed point. Over time, I moved the feed point to near the back of the tuner with a short 3in length of coax, and ran a random length of 300ohm ribbon to the feed point of the dipole. Later after reading about the G5RV, I extended each leg to 16m long. It is important to note that while similar to a G5RV, my antenna does not feature the same length of ribbon as a G5RV. The antenna is not mounted up high, the apex would be at gutter level (we have a two- storey house here). Legs tie off no higher than 2m in the air. One end ties off to a frangipannie (sp?) tree in our front yard, the other to a piece of rope running to a macadamia tree in our back yard. I have a feeling the frangipannie is helping form part of the antenna. This antenna, while quite deaf I find on the 10m band, has worked into VK5 on 15m, I have had contacts into ZL on 20m, and it works quite well locally on 40m and 80m. I have had successful contacts using QRP power levels on 80m with this antenna, and it is very easy to tune there. It has broken once or twice. It has never taken me any longer than about 15 minutes to repair and get back up in the air. It's also cheap enough to consider being disposable, should disaster truly strike. So I say, go for it … it might as well do something useful. Regards, Stuart VK4MSL |
Using speaker wire for a dipole
A local job lot store was selling 100' rolls of #18 speaker wire. I bought as many as I could. I use it for not only hf antennas, but am making open wire line with discarded Bic pens as separators (there was an article in QST about this). I have had a lot of success with this.
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Using speaker wire for a dipole
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