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cantenna
"KC8QJP" wrote in message . .. a crisco can works well http://www.radiobanter.com/showpost....73&postcount=1 |
cantenna
"RF BURNS" wrote in message ... "KC8QJP" wrote in message . .. a crisco can works well http://www.radiobanter.com/showpost....73&postcount=1 leave the crisco in it and after tuning up you can fry your dinner! |
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In article IDh7l.451354$TT4.408322@attbi_s22, Erich
wrote: Jim-NN7K wrote: funkbastler wrote: On Thu, 01 Jan 2009 17:41:27 +0000, Dave wrote: KC8QJP wrote: a crisco can works well http://www.mfjenterprises.com/Produc...uctid=MFJ-250X Where's a good place to find transformer oil (besides at the top of the utility pole outside the house)? Or, what's an acceptable substitute? Mineral Oil (available at your local drug store). Just be prepared for some strange looks when you purchase a gallon of mineral oil all at once. :-O yup, that's what I used when I got my ticket many years ago to fill up my cantenna. Still have it in the closet but haven't used it in years! |
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Billy Burpelson wrote:
Barry L. Ornitz, PhD WA4VZQ wrote: Silicone oils are excellent from a health standpoint... John Smith wrote: However, the last silicone oil I purchased was at an auction... and food grade to boot!) I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Inquiring minds want to know. There are plenty of things that are inert when passing through the gut that will be lethal if introduced directly into the body. |
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On Fri, 02 Jan 2009 15:36:17 -0500, Billy Burpelson wrote:
I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Plaintiffs' lawyers and defendants' lawyers.... |
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Billy Burpelson wrote:
... I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Inquiring minds want to know. A friend of mine, in the medical profession, once told me there is only 3 things she knew of which the body would "tolerate" as implant materials: teflon/nylon, glass, and some grades of stainless steel ... I don't know, but seems like diamond would be ok, doesn't it? Others substances? Perhaps she was only speaking of the materials she has seen, next time I see her, I will ask ... you have me curious now. Regards, JS |
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Billy Burpelson wrote: Barry L. Ornitz, PhD WA4VZQ wrote: Silicone oils are excellent from a health standpoint... John Smith wrote: However, the last silicone oil I purchased was at an auction... and food grade to boot!) I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Inquiring minds want to know. Kenneth P. Stox wrote: There are plenty of things that are inert when passing through the gut that will be lethal if introduced directly into the body. And swallowing something is -not- being "introduced directly into the body"? I would have thought otherwise... |
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"RF BURNS" wrote in message ... "KC8QJP" wrote in message . .. a crisco can works well http://www.radiobanter.com/showpost....73&postcount=1 Dave wrote: leave the crisco in it and after tuning up you can fry your dinner! ....and fry your arteries with all the cholesterol! |
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Billy Burpelson wrote:
... And swallowing something is -not- being "introduced directly into the body"? I would have thought otherwise... I mean, "Come on!" You have to ask that? A hypodermic needles injection is "directly." A swallowed substance is directly introduced into the digestive tract, where it is the assimilated into the blood ... Another example? A bullet from a gun is "directly" introduced into the body, a swallowed bullet is not ... Regards, JS |
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On Jan 2, 2:16*pm, "Kenneth P. Stox" wrote:
Billy Burpelson wrote: Barry L. Ornitz, PhD * WA4VZQ wrote: Silicone oils are excellent from a health standpoint... John Smith wrote: However, the last silicone oil I purchased was at an auction... and food grade to boot!) I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Inquiring minds want to know. - There are plenty of things that are inert when - passing through the gut that will be lethal if - introduced directly into the body. Yeah - You can Sallow a FMJ Bullet and 'pass-it' quite nicely. -fwiw- a Solid Lead Bullet might produce different results in the 'gut'. But that same FMJ Bullet 'passing-thru' the Body could be very Lethal. |
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Bob Campbell wrote:
John Smith wrote: Dave wrote: ... http://www.eham.net/forums/Elmers/1574 Uh, yeah, I guess your reference to a dummy load is helpful, in some other reality ... I was just happy to see someone in that thread pop up with the warning about PCBs in old transformer oil. I couldn't believe someone said they actually got power company transformer oil! After I refurbished my Cantenna (needed a new globar resistor and cleaning), I was able to get a gallon from my local power company (free gratis). It took a few phone calls to find the supervisor of the transformer shop. At the rate their pump runs, the trick was getting /only/ one gallon! I considered mineral oil but learned transformer oil has better thermal characteristics. I now have a homebrew air-cooled dummy load that will handle over a kilowatt continuously. Bryan WA7PRC |
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On Jan 3, 12:31*am, "Bryan" wrote:
Bob Campbell wrote: John Smith wrote: Dave wrote: ... http://www.eham.net/forums/Elmers/1574 Uh, yeah, I guess your reference to a dummy load is helpful, in some other reality ... I was just happy to see someone in that thread pop up with the warning about PCBs in old transformer oil. * I couldn't believe someone said they actually got power company transformer oil! After I refurbished my Cantenna (needed a new globar resistor and cleaning), I was able to get a gallon from my local power company (free gratis). *It took a few phone calls to find the supervisor of the transformer shop. *At the rate their pump runs, the trick was getting /only/ one gallon! I considered mineral oil but learned transformer oil has better thermal characteristics. *I now have a homebrew air-cooled dummy load that will handle over a kilowatt continuously. Bryan WA7PRC I used Shell Diala for years in radar systems. The last time I changed the oil we used somrthing else, probably cheaper. The main ingredient in all odf it is mineral oil but it has a few additives. Local PoCO uses the same. We got some from them one time and they had a RR tank car full of it. Jimmie |
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Billy Burpelson wrote: ... And swallowing something is -not- being "introduced directly into the body"? I would have thought otherwise... John Smith wrote: I mean, "Come on!" You have to ask that? A hypodermic needles injection is "directly." A swallowed substance is directly introduced into the digestive tract, where it is the assimilated into the blood ... Huh? Are we both saying the same thing? If a substance is injected by a hypodermic needle and then 'assimilated into the blood', how is that different from you saying "A swallowed substance is directly introduced into the digestive tract, where it is the[n] assimilated into the blood ..."? Seems like it gets into the blood stream (and is thus circulated around the entire body) in -either- case. So your point is...? Back to my original, bottom line question: is silicone in the blood stream good for you or bad for you? (and yes, I DO have to ask, because your response seems to make no sense). Regards, Billy |
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Billy Burpelson wrote:
Back to my original, bottom line question: is silicone in the blood stream good for you or bad for you? (and yes, I DO have to ask, because your response seems to make no sense). Yes. Ask the women whose breast implants broke. - 73 de Mike N3LI - |
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In rec.radio.amateur.antenna Mike Coslo wrote:
Billy Burpelson wrote: Back to my original, bottom line question: is silicone in the blood stream good for you or bad for you? (and yes, I DO have to ask, because your response seems to make no sense). Yes. Ask the women whose breast implants broke. Or you could ask the Mayo Clinic which says the only problem is the formation of scar tissue, which happens with any foreign object in the body. http://www.mayoclinic.com/health/bre...plants/AN01212 -- Jim Pennino Remove .spam.sux to reply. |
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In rec.radio.amateur.antenna Billy Burpelson wrote:
Billy Burpelson wrote: ... And swallowing something is -not- being "introduced directly into the body"? I would have thought otherwise... John Smith wrote: I mean, "Come on!" You have to ask that? A hypodermic needles injection is "directly." A swallowed substance is directly introduced into the digestive tract, where it is the assimilated into the blood ... Huh? Are we both saying the same thing? If a substance is injected by a hypodermic needle and then 'assimilated into the blood', how is that different from you saying "A swallowed substance is directly introduced into the digestive tract, where it is the[n] assimilated into the blood ..."? Seems like it gets into the blood stream (and is thus circulated around the entire body) in -either- case. So your point is...? Back to my original, bottom line question: is silicone in the blood stream good for you or bad for you? (and yes, I DO have to ask, because your response seems to make no sense). It is not very likely to be "good" for you and depending on how much, it could be "bad" for you. But there is the bottom line question of how could an oranically inert substance get into the blood stream other than through direct injection? The question is like asking if glass in the blood stream is a problem. -- Jim Pennino Remove .spam.sux to reply. |
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On Fri, 2 Jan 2009 01:35:16 -0500, "NoSPAM"
wrote: However, the Cantenna relies on natural convection of the oil for cooling and the higher viscosity of commonly available silicone oils will limit the power handling capability of the Cantenna. So, a low density fluid would be the better choice? If that were the prime criteria, I would think that water or antifreeze would be the best. If having convection currents agitate the fluid is important, it would be easy enough to install a paddle stirrer and thermometer. Oh wait. This is ham radio. Forget the thermometer. I'm also wondering if the electrical characteristics of water are an issue for an HF dummy load. Even if someone dumps salt water into the paint can, the conduction losses to ground from the resistor to the can ground can't be all that much below 30MHz. Thermal Conductivity Viscosity W/mK cSt @20c Water 0.6 0.9 AF (glycol) 0.24 2.0 Water+AF 0.8(?) 1.5 50%/50% Silicon Oil 0.1 varies radically Mineral Oil 0.138 34.5 Fluorinert FC-77 0.063 0.75 Ok, I see why. Water has 1/5th of the thermal conductivity of mineral oil. 50/50 water and antifreeze won't work. That raises the boiling point but ruins the thermal conductivity. Pure ethylene glycol looks tolerable. Other than the health and ecology issues, any reason that 100% antifreeze won't work? Incidentally my theory is that the Heath engineers of the 1960's used mineral oil because that's what's inside a Lava Lamp. They were probably designing Heathkit Lava Lamps but when that failed, they had to do something useful with the mineral oil. Remember that the Cantenna must be de-rated when used for long duty cycles, and a high viscosity oil will lower the power rating still more. Also remember that silicone oils are not cheap (and my buddy at Dow would only send me small samples). Well, if you want expensive and near perfect, there's 3M Fluoinert. http://en.wikipedia.org/wiki/Fluorinert http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtnxTE5X46EVuQEcuZgVs 6EVs6E666666-- About $400/liter for recycled FC-77 and $2,200/liter for the new FC-770 stuff from various 3M dealers. A 1 gallon cantenna required 3.78 liters or about $1,500 in recycled FC-77. For those hams that want the very best. Gold plated paint can is optional. I would suggest using modern RF terminations made by Bourns and other companies. These are designed to be bolted to a large heatsink. The CHF9838CNF series is rated for 50 ohms, 250 watts, VSWR below 1.1 from DC to 2.2 GHz. It only costs $27.50 in single lot quantities. I think this is higher than the continuous rating of the Cantenna. I don't know for sure as I disposed of my Cantenna years ago. Digi-Key sells these Bourns terminations if you want one. Nice. Thanks. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CHF9838CNF500L-ND http://www.mouser.com/Search/Refine.aspx?Msid=65210000&Keyword=CHF9838CNF500L http://www.bourns.com/data/global/PDFs/CHF9838CNF.pdf I kinda prefer to use 4ea 200 ohm loads in parallel. In a previous power amp design, I had to dump 200 watts into a load if the antenna failed. The thermal resistance of the flange mount was too high for one device to handle the load at the rated temperatures. However, 4 devices did the trick. Barry L. Ornitz, PhD WA4VZQ -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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In article ,
Jeff Liebermann wrote: I'm also wondering if the electrical characteristics of water are an issue for an HF dummy load. Even if someone dumps salt water into the paint can, the conduction losses to ground from the resistor to the can ground can't be all that much below 30MHz. It's probably not worth much, but here's some anecdotal evidence. About 50 years ago several of us at W8LT (The Ohio State University amateur radio club) needed a low-power dummy load to be used at moderate frequencies (e.g. 20 meters). I came up with the idea of immersing a 2 watt, 51 ohm carbon resistor in a large glass of Columbus, Ohio tap water. We found that at 14 MHz putting the resistor under water made negligible change in observed SWR, which surprised me because Columbus water (unlike the stuff we're blessed with here in the Vancouver, BC area which comes right from the mountain snow-pack) was fairly hard. This also indicated that the water didn't put too much capacitance in parallel with the resistance. Water-cooling did allow the 2 watt resistor to absorb a fair bit more power than 2 watts, at least for a while until the water heated up too much. Thermal Conductivity Viscosity W/mK cSt @20c Water 0.6 0.9 AF (glycol) 0.24 2.0 Water+AF 0.8(?) 1.5 50%/50% Silicon Oil 0.1 varies radically Mineral Oil 0.138 34.5 Fluorinert FC-77 0.063 0.75 Ok, I see why. Water has 1/5th of the thermal conductivity of mineral oil. It's still a heck of a lot better than air. As I recall, we were in a hurry, we had the resistor, and we didn't have any suitable oil on hand. David. ex-W8EZE -- David Ryeburn To send e-mail, use "ca" instead of "caz". |
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On Sat, 03 Jan 2009 18:53:59 -0800, Jeff Liebermann
wrote: Thermal Conductivity Viscosity W/mK cSt @20c Water 0.6 0.9 AF (glycol) 0.24 2.0 Water+AF 0.8(?) 1.5 50%/50% Silicon Oil 0.1 varies radically Mineral Oil 0.138 34.5 Fluorinert FC-77 0.063 0.75 Air 0.025 Copper 370. Diamond 1000. Ok, I see why. Water has 1/5th of the thermal conductivity of mineral oil. 50/50 water and antifreeze won't work. That raises the boiling point but ruins the thermal conductivity. Pure ethylene glycol looks tolerable. Other than the health and ecology issues, any reason that 100% antifreeze won't work? Sorry, I goofed. Vicodin etc. It should be the higher the W/mK, the better the thermal conductivity. So why is Fluorinert favored for cooling when it has such a lousy thermal conductivity? http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtnxTE5X46EVuQEcuZgVs 6EVs6E666666-- Since it's usually circulated with a pump and involves direct immersion, is it because of it's low viscosity and superior electrical characteristics? It would also appear that water has 5 times the thermal conductivity than mineral oil. So, why use mineral oil? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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Jeff Liebermann wrote:
On Sat, 03 Jan 2009 18:53:59 -0800, Jeff Liebermann wrote: Thermal Conductivity Viscosity W/mK cSt @20c Water 0.6 0.9 AF (glycol) 0.24 2.0 Water+AF 0.8(?) 1.5 50%/50% Silicon Oil 0.1 varies radically Mineral Oil 0.138 34.5 Fluorinert FC-77 0.063 0.75 Air 0.025 Copper 370. Diamond 1000. Ok, I see why. Water has 1/5th of the thermal conductivity of mineral oil. 50/50 water and antifreeze won't work. That raises the boiling point but ruins the thermal conductivity. Pure ethylene glycol looks tolerable. Other than the health and ecology issues, any reason that 100% antifreeze won't work? Sorry, I goofed. Vicodin etc. It should be the higher the W/mK, the better the thermal conductivity. So why is Fluorinert favored for cooling when it has such a lousy thermal conductivity? http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtnxTE5X46EVuQEcuZgVs 6EVs6E666666-- Since it's usually circulated with a pump and involves direct immersion, is it because of it's low viscosity and superior electrical characteristics? It would also appear that water has 5 times the thermal conductivity than mineral oil. So, why use mineral oil? It doesn't turn to steam or otherwise evaporate. Dave WD9BDZ |
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Jeff Liebermann wrote:
... ... The thermal resistance of the flange mount was too high for one device to handle the load at the rated temperatures. However, 4 devices did the trick. Barry L. Ornitz, PhD WA4VZQ Yeah, all that, and then try to sink 5KW+ into a paint can ... 20 X 1000 ohm resistors is very minimum, in a tubular aluminum heat-sink-no less, in my humble opinion ... as when you are in key-down, and your attention is diverted, things can get warm, quickly, or so it seems! Regards, JS |
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In article ,
Jeff Liebermann wrote: On Sat, 03 Jan 2009 18:53:59 -0800, Jeff Liebermann wrote: Thermal Conductivity Viscosity W/mK cSt @20c Water 0.6 0.9 AF (glycol) 0.24 2.0 Water+AF 0.8(?) 1.5 50%/50% Silicon Oil 0.1 varies radically Mineral Oil 0.138 34.5 Fluorinert FC-77 0.063 0.75 Air 0.025 Copper 370. Diamond 1000. Ok, I see why. Water has 1/5th of the thermal conductivity of mineral oil. 50/50 water and antifreeze won't work. That raises the boiling point but ruins the thermal conductivity. Pure ethylene glycol looks tolerable. Other than the health and ecology issues, any reason that 100% antifreeze won't work? Sorry, I goofed. Vicodin etc. It should be the higher the W/mK, the better the thermal conductivity. So why is Fluorinert favored for cooling when it has such a lousy thermal conductivity? High resistivity High dielectric strength Low maintenance Low corrosion = very compatible with most materials Leaks don't cause more damage low viscosity Wide useful temperature range http://multimedia.3m.com/mws/mediawe...E5X46EVuQEcuZg Vs6EVs6E666666-- Since it's usually circulated with a pump and involves direct immersion, is it because of it's low viscosity and superior electrical characteristics? It would also appear that water has 5 times the thermal conductivity than mineral oil. So, why use mineral oil? DI water is very corrosive and requires stainless steel heat transfer radiators among other components. It is difficult to keep uncontaminated and you have to keep changing filters for example. Get a leak and it usually causes additional damage. Mineral oil makes a mess and is old technology. I know of one ATE manufacture that used DI water for cooling in the mainframe and test head. What a mistake that was. Every time they had a leak in the test head expensive boards got damaged. -- Telamon Ventura, California |
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On Jan 4, 3:21*am, Telamon
wrote: In article , *Jeff Liebermann wrote: On Sat, 03 Jan 2009 18:53:59 -0800, Jeff Liebermann wrote: * * * * *Thermal Conductivity * * Viscosity * * * * * * * * *W/mK * * * * * * * * cSt @20c Water * * * * * * 0.6 * * * * * * * * *0..9 AF (glycol) * * * 0.24 * * * * * * * * 2.0 Water+AF * * * * *0.8(?) * * * * * * * 1.5 * 50%/50% Silicon Oil * * * 0.1 * * * * * * * * *varies radically Mineral Oil * * * 0.138 * * * * * * * *34.5 Fluorinert FC-77 *0.063 * * * * * * * *0.75 *Air * * * * * * * 0.025 *Copper * * * * *370. *Diamond * * * *1000. Ok, I see why. *Water has 1/5th of the thermal conductivity of mineral oil. *50/50 water and antifreeze won't work. *That raises the boiling point but ruins the thermal conductivity. *Pure ethylene glycol looks tolerable. *Other than the health and ecology issues, any reason that 100% antifreeze won't work? Sorry, I goofed. *Vicodin etc. *It should be the higher the W/mK, the better the thermal conductivity. * So why is Fluorinert favored for cooling when it has such a lousy thermal conductivity? High resistivity High dielectric strength Low maintenance Low corrosion = very compatible with most materials Leaks don't cause more damage low viscosity Wide useful temperature range http://multimedia.3m.com/mws/mediawe...SLXTtnxTE5X46E.... Vs6EVs6E666666-- Since it's usually circulated with a pump and involves direct immersion, is it because of it's low viscosity and superior electrical characteristics? It would also appear that water has 5 times the thermal conductivity than mineral oil. *So, why use mineral oil? DI water is very corrosive and requires stainless steel heat transfer radiators among other components. It is difficult to keep uncontaminated and you have to keep changing filters for example. Get a leak and it usually causes additional damage. Mineral oil makes a mess and is old technology. I know of one ATE manufacture that used DI water for cooling in the mainframe and test head. What a mistake that was. Every time they had a leak in the test head expensive boards got damaged. -- Telamon Ventura, California- Hide quoted text - - Show quoted text - No kidding on how messy mineral oil can be. I had a leak in a recirculating pump and it put about 20 gal of oil on the carpeted floor of the radar site. We had to take up the carpet and the asphalt tile. The floor is now bare concrete because carpet is forbidden around oil and the concrete will not take adhesive to put down new tile. Jimmie |
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"Allodoxaphobia" wrote in message ... On Fri, 02 Jan 2009 15:36:17 -0500, Billy Burpelson wrote: I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Plaintiffs' lawyers and defendants' lawyers.... In the food industry, it is necessary to provide lubricants, coolants, etc., for the proper operation of equipment and preparation of product. The same holds true in the pharmaceutical/medical device industries, where silicone (medical grade 360) is used to lubricate rubber stoppers which are inserted by machine into vials, etc. There are at least 2 classifications: (1) product contact, and (2) incidental product contact. These are essentially the same; just a matter of degree. They (silicones) are not a food ingredient. HankG |
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"JB" wrote in message ... Mineral Oil (available at your local drug store). Just be prepared for some strange looks when you purchase a gallon of mineral oil all at once. :-O Is motor oil a conductor? Might burn and sludge up your resistor. Lots of additives you just don't need. I had a cantenna for 20 years with light mineral oil. there was a little seepage to the top of the lid through the vent. I actually had transformer oil but never used it because of the thought of that stuff seeping. It really is a lot cleaner. Check feed stores, Vet supply stores, paint stores, hardware. Check this out: http://www.pugetsystems.com/submerged.php When I was in the Navy, we had some gear that used a high power TWT. It was immersed in a bath of a fluorocarbon called FC-75, trade name Fluorinert. Good heat conductor, great insulator, totally inert. Supposedly, you could drink it. It's still around. Google FC-75 and wikipedia will tell you all about it. $68/ten gallons is a little pricey for my Cantenna but you might not think so. Here's a summary of that chemical family's characteristics for the curious: http://www.acota.co.uk/products/fluo...tronic-liquids |
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"John Smith" wrote in message ... Jeff Liebermann wrote: ... ... The thermal resistance of the flange mount was too high for one device to handle the load at the rated temperatures. However, 4 devices did the trick. Barry L. Ornitz, PhD WA4VZQ Yeah, all that, and then try to sink 5KW+ into a paint can ... 20 X 1000 ohm resistors is very minimum, in a tubular aluminum heat-sink-no less, in my humble opinion ... as when you are in key-down, and your attention is diverted, things can get warm, quickly, or so it seems! That's where the crisco comes in handy! Regards, JS |
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"HankG" wrote in message ... "Allodoxaphobia" wrote in message ... On Fri, 02 Jan 2009 15:36:17 -0500, Billy Burpelson wrote: I am a bit puzzled. IIRC, the silicone in women's breast implants would/could/did leak and cause fairly serious health problems. Yet, Dr. Ornitz says "Silicone oils are excellent from a health standpoint" and Mr. Smith says: "food grade". Could anyone take a shot at explaining this apparent dichotomy? Plaintiffs' lawyers and defendants' lawyers.... In the food industry, it is necessary to provide lubricants, coolants, etc., for the proper operation of equipment and preparation of product. The same holds true in the pharmaceutical/medical device industries, where silicone (medical grade 360) is used to lubricate rubber stoppers which are inserted by machine into vials, etc. There are at least 2 classifications: (1) product contact, and (2) incidental product contact. These are essentially the same; just a matter of degree. They (silicones) are not a food ingredient. The crisco is! HankG |
cantenna
"Billy Burpelson" wrote in message ... "RF BURNS" wrote in message ... "KC8QJP" wrote in message . .. a crisco can works well http://www.radiobanter.com/showpost....73&postcount=1 Dave wrote: leave the crisco in it and after tuning up you can fry your dinner! ...and fry your arteries with all the cholesterol! We make deep fried fatback sandwiches with it. |
cantenna
Modern dielectric oil (aka transformer oil) is refined mineral oil
with an antioxidant (tocopherol, BHA, or BHT) added to retard spoiling. Shell Diala AX ExxonMobil Univolt 65 are the two major kinds (there's one from Castrol,too) Both are sold (in 5 gallon pails, typically, as a minimum quantity) by "jobbers" which can be found on the mfr's website (you enter a zip code and gives you the distributors within X miles), or by looking in the yellow pages under Oil,Lubricants-Jobbers. Used to be in the $4-5/ gallon range, but I just was talking to someone who had to pay around $50 for a 5gallon pail. (probably a hangover from $100/bbl crude prices) You *can* use USP White Mineral Oil (laxative) available in pints at the drugstore, gallons at the feedstore (If you've got a colicky horse, gallons are the quantity wanted), but it's a) more expensive b) not water content controlled For HV dielectric purposes water content (in the ppm range) is important. So is particulate contamination. For a dummy load, probably not so much. Another inexpensive source of mineral oil without many additives is hydraulic oil (as used in, say, tractors, etc.). Even "straight weight" motor oil without additives/detergents can work (look for the SAE 10,15, or 20 viscosities).. it can be VERY cheap on sale as a "loss leader" to get folks into the store (since nobody in their right mind would actually run this in an engine) For a dummy load, viscosity IS important, because convective flow is important. (viscosity change with temperature, too...) Silicone would be massive overkill, and we won't even get into Fluorinert. BTW, if you spill mineral oil, it cleans up nicely with detergent and water.. the same cannot be said of silicone or FC-xx.. Silicone oils are almost impossible to remove. Jim, w6rmk |
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On Jan 1, 9:49*am, "KC8QJP" wrote:
"John Passaneau" wrote in message ... KC8QJP wrote: a crisco can works well Sometimes you can get empty paint cans at professional paint supplies stores. They are nice as they are clean and shiny. John W3JXP Thanks for the tip! Yes. I did that The new can had a plastic type coating on the inside to prevent any possible leaks and corrosion, a great improvement over cans of yesteryear that leaked on to the floor over time. Same story for the lid., Cost me something like $3 and well worth it. Art |
cantenna
wrote in message
... Modern dielectric oil (aka transformer oil) is refined mineral oil with an antioxidant (tocopherol, BHA, or BHT) added to retard spoiling. Mineral oil does not "spoil" in the sense that animal or vegetable fats (long chain carboxylic acids) do. Tocopherol (Vitamin E), butylated-hydroxyanisole and butylated-hydroxytoluene are used (in the low part per million range) to prevent oxidation of the oil which produces "sludge" and "varnish" (here used as referring to deposits from hydrocarbons such as gasoline on fuel tanks and carburetters). All three compounds are also used in the food industry - to prevent spoilage. :-) Shell Diala AX ExxonMobil Univolt 65 are the two major kinds (there's one from Castrol,too) Both are sold (in 5 gallon pails, typically, as a minimum quantity) by "jobbers" which can be found on the mfr's website (you enter a zip code and gives you the distributors within X miles), or by looking in the yellow pages under Oil,Lubricants-Jobbers. Used to be in the $4-5/ gallon range, but I just was talking to someone who had to pay around $50 for a 5gallon pail. (probably a hangover from $100/bbl crude prices) You *can* use USP White Mineral Oil (laxative) available in pints at the drugstore, gallons at the feedstore (If you've got a colicky horse, gallons are the quantity wanted), but it's a) more expensive b) not water content controlled For HV dielectric purposes water content (in the ppm range) is important. So is particulate contamination. For a dummy load, probably not so much. The partioning coefficient of agricultural grade white mineral oil is greater than one million. Dissolved water will have no measurable effect on the dummy load. Another inexpensive source of mineral oil without many additives is hydraulic oil (as used in, say, tractors, etc.). Even "straight weight" motor oil without additives/detergents can work (look for the SAE 10,15, or 20 viscosities).. it can be VERY cheap on sale as a "loss leader" to get folks into the store (since nobody in their right mind would actually run this in an engine) For good natural convection around and through the Kanthal-Globar silicon carbide resistor used in the Cantenna, I would use no higher a viscosity oil than SAE 5. For a dummy load, viscosity IS important, because convective flow is important. (viscosity change with temperature, too...) Most organic oils are less viscous at higher temperatures. This is good in the Cantenna application. The lubricating properties of the oil are unimportant here. Silicone would be massive overkill, and we won't even get into Fluorinert. BTW, if you spill mineral oil, it cleans up nicely with detergent and water.. the same cannot be said of silicone or FC-xx.. Silicone oils are almost impossible to remove. This is an excellent point. Freon TF® (1,1,2-trichloro-1,2,2-trifluoroethane) was excellent for removing silicone oils and greases, and it had a number of physical properties that made it ideal for many electronic applications. It is too bad that it is banned as a ozone destroying chlorofluorocarbon. In looking at some of the alternatives for cleaning away silicone oils, I would suggest looking at Caig Laboratories (makers of DeoxIT®) CaiKleen NF which is mainly 1,1,1,3,3-pentafluoropropane. Unfortunately its boiling point is 15 C (59 F) and it is quite expensive. Good post, Jim! 73, Dr. Barry L. Ornitz WA4VZQ |
cantenna
Art Unwin wrote:
On Jan 1, 9:49 am, "KC8QJP" wrote: "John Passaneau" wrote in message ... KC8QJP wrote: a crisco can works well Sometimes you can get empty paint cans at professional paint supplies stores. They are nice as they are clean and shiny. John W3JXP Thanks for the tip! Yes. I did that The new can had a plastic type coating on the inside to prevent any possible leaks and corrosion, a great improvement over cans of yesteryear that leaked on to the floor over time. Same story for the lid., Cost me something like $3 and well worth it. Art The hole in the lid of a Heathkit Cantenna was to allow for expansion due to heat buildup in the oil during heavy use. Make sure you allow for this expansion in any sealed container if you roll your own cantenna. Dave WD9BDZ |
cantenna
NoSPAM wrote:
wrote in message ... Modern dielectric oil (aka transformer oil) is refined mineral oil with an antioxidant (tocopherol, BHA, or BHT) added to retard spoiling. Mineral oil does not "spoil" in the sense that animal or vegetable fats (long chain carboxylic acids) do. Tocopherol (Vitamin E), butylated-hydroxyanisole and butylated-hydroxytoluene are used (in the low part per million range) to prevent oxidation of the oil which produces "sludge" and "varnish" (here used as referring to deposits from hydrocarbons such as gasoline on fuel tanks and carburetters). All three compounds are also used in the food industry - to prevent spoilage. :-) Shell Diala AX ExxonMobil Univolt 65 are the two major kinds (there's one from Castrol,too) Both are sold (in 5 gallon pails, typically, as a minimum quantity) by "jobbers" which can be found on the mfr's website (you enter a zip code and gives you the distributors within X miles), or by looking in the yellow pages under Oil,Lubricants-Jobbers. Used to be in the $4-5/ gallon range, but I just was talking to someone who had to pay around $50 for a 5gallon pail. (probably a hangover from $100/bbl crude prices) You *can* use USP White Mineral Oil (laxative) available in pints at the drugstore, gallons at the feedstore (If you've got a colicky horse, gallons are the quantity wanted), but it's a) more expensive b) not water content controlled For HV dielectric purposes water content (in the ppm range) is important. So is particulate contamination. For a dummy load, probably not so much. The partioning coefficient of agricultural grade white mineral oil is greater than one million. Dissolved water will have no measurable effect on the dummy load. Another inexpensive source of mineral oil without many additives is hydraulic oil (as used in, say, tractors, etc.). Even "straight weight" motor oil without additives/detergents can work (look for the SAE 10,15, or 20 viscosities).. it can be VERY cheap on sale as a "loss leader" to get folks into the store (since nobody in their right mind would actually run this in an engine) For good natural convection around and through the Kanthal-Globar silicon carbide resistor used in the Cantenna, I would use no higher a viscosity oil than SAE 5. For a dummy load, viscosity IS important, because convective flow is important. (viscosity change with temperature, too...) Most organic oils are less viscous at higher temperatures. This is good in the Cantenna application. The lubricating properties of the oil are unimportant here. Silicone would be massive overkill, and we won't even get into Fluorinert. BTW, if you spill mineral oil, it cleans up nicely with detergent and water.. the same cannot be said of silicone or FC-xx.. Silicone oils are almost impossible to remove. This is an excellent point. Freon TF® (1,1,2-trichloro-1,2,2-trifluoroethane) was excellent for removing silicone oils and greases, and it had a number of physical properties that made it ideal for many electronic applications. It is too bad that it is banned as a ozone destroying chlorofluorocarbon. In looking at some of the alternatives for cleaning away silicone oils, I would suggest looking at Caig Laboratories (makers of DeoxIT®) CaiKleen NF which is mainly 1,1,1,3,3-pentafluoropropane. Unfortunately its boiling point is 15 C (59 F) and it is quite expensive. Good post, Jim! 73, Dr. Barry L. Ornitz WA4VZQ Hi all: Great post with lots of good info. But look for a power line transformer there are very high voltages and a lot of power. In a Ham dummy load the max voltage on the resistor would be about 275V at 1500w. Unless your a CB'er you will not see more than that. So hundreds, my self includeDd Ham's have use common mineral oil from the drug store with fine results. So go for it. The last time I was took part in filling a dummy load was back in the seventy's. I was helping friend move into a new house and set up the ham shack. We needed to get new oil for the dummy load as we had dumped the old oil rather than move it full and take the chance of it spilling. So we went to the store and got the oil and along with it we picked up some water glasses and repair parts for a toilet. The check out girl looked at us kind of funny and I really did my friend reputation in by telling her we had found a new way to turn on... John Passaneau, W3JXP |
cantenna
John Passaneau wrote:
Great post with lots of good info. But look for a power line transformer there are very high voltages and a lot of power. In a Ham dummy load the max voltage on the resistor would be about 275V at 1500w. Unless your a CB'er you will not see more than that. So hundreds, my self includeDd Ham's have use common mineral oil from the drug store with fine results. The issue isn't the water content or particulate contamination (which affect the HV behavior) but the viscosity. Diala AX (for instance) is quite low viscosity. 9.7 cSt/56 SUS at 40C, 2.3cSt/34SUS at 100C http://www.nttworldwide.com/docs/diala-ax.pdf 9cSt (mm^2/s) is about the dividing line between SAW 20 and 30 AT 100C, so Diala AX is a lot less viscous than even 20 weight motor oil (2.3cSt vs 9.3 cSt) The typical Mineral Oil, USP, heavy at a drug store is around 34cSt viscosity (3-4 times heavier). Diala pours pretty readily.. I'd say about like half and half, but not as thick as whipping cream. That's important for the heat transfer, because you need the circulation inside the load (unless you're just pulsing it..) By the way, that's why the rating on the Cantenna is different for USP mineral oil and insulating oil. http://www.mfjenterprises.com/man/pdf/MFJ-250.pdf for 10minute duration, the rating is about 60% when using mineral oil instead of transformer oil. For long durations, the whole thing gets hot and reaches thermal equilibrium. For short durations, the lower viscosity transformer oil moves the heat away from the resistor faster keeping it at lower temperature. That said, most hams aren't going to run their dummy load at full power for 10 minutes at a crack. |
cantenna
On Jan 1, 8:34*pm, "Bob Campbell" wrote:
"JIMMIE" wrote in message ... Nothing wrong with PoCo oil. They havent used PCBs in years. We use the same stuff at work made by Shell . Its just mineral oil with a few additives. That's good to know. I have a 200 watt air cooled dummy load made of 2 watt resistors. I was curious as to how much power it could safley disipate if placed in a gallon container of mineral oil. It seems to handle 200 watts continuously with just a muffin fan on it. Jimmie |
cantenna
JIMMIE wrote:
On Jan 1, 8:34 pm, "Bob Campbell" wrote: "JIMMIE" wrote in message ... Nothing wrong with PoCo oil. They havent used PCBs in years. We use the same stuff at work made by Shell . Its just mineral oil with a few additives. That's good to know. I have a 200 watt air cooled dummy load made of 2 watt resistors. I was curious as to how much power it could safley disipate if placed in a gallon container of mineral oil. It seems to handle 200 watts continuously with just a muffin fan on it. Jimmie Not an easy question to answer. allot depends on how the thing is made. How much power it can handle is controlled by how fast the heat can be moved away. It doesn't matter if it's oil or air. In oil the speed is set by how obstructed the path the hot oil would need to travel to get away from the part thats making the heat. I think the resistor in a cantenna in free air is only good for about 50 watts but it designed for the smooth passage of the oil around the resistor. I don't think that your mass of 2 watt resistors will allow the oil to pass freely enough to get to a KW for vary long. If you used a pump to move the oil it would work better in the same way that a fan works. John Passaneau |
cantenna
One other thing might check out, is the Salt Water Dummy Loads
(on several web sites). One mearly uses (can, Jar with lid), and with metal plates attached to coax connector, filled with salt water - Fill with water, then with ohm meter , add Salt until the brine hits 50 ohms! Tho, don't know how high frequency it is reliable to, should work to at least 50 MHz. Jim NN7K John Passaneau wrote: JIMMIE wrote: On Jan 1, 8:34 pm, "Bob Campbell" wrote: "JIMMIE" wrote in message ... Nothing wrong with PoCo oil. They havent used PCBs in years. We use the same stuff at work made by Shell . Its just mineral oil with a few additives. That's good to know. I have a 200 watt air cooled dummy load made of 2 watt resistors. I was curious as to how much power it could safley disipate if placed in a gallon container of mineral oil. It seems to handle 200 watts continuously with just a muffin fan on it. Jimmie Not an easy question to answer. allot depends on how the thing is made. How much power it can handle is controlled by how fast the heat can be moved away. It doesn't matter if it's oil or air. In oil the speed is set by how obstructed the path the hot oil would need to travel to get away from the part thats making the heat. I think the resistor in a cantenna in free air is only good for about 50 watts but it designed for the smooth passage of the oil around the resistor. I don't think that your mass of 2 watt resistors will allow the oil to pass freely enough to get to a KW for vary long. If you used a pump to move the oil it would work better in the same way that a fan works. John Passaneau |
cantenna [salt water dummy loads]
"Jim-NN7K" . wrote in message
... One other thing might check out, is the Salt Water Dummy Loads (on several web sites). One mearly uses (can, Jar with lid), and with metal plates attached to coax connector, filled with salt water - Fill with water, then with ohm meter , add Salt until the brine hits 50 ohms! Tho, don't know how high frequency it is reliable to, should work to at least 50 MHz. Jim NN7K Back in the mid-1960's there was an article in QST where they did this. The load will definitely be frequency dependent as demonstrated by experimental results. Also the salt used will effect the results. From a theoretical standpoint, the mobility of ions is dependent on the size of the ion. The bigger the ion, the slower it will move. This conveniently explains much of what is seen in ground losses and is why electrolytic capacitors are essentially useless above 1 MHz. The ions cannot move fast enough in the small times seen per cycle, so the current falls off. Ion mobility also decreases as the temperature drops which explains why electrolytic capacitors also do poorly at low temperatures. I have done as Jim suggested when testing a kilowatt amplifier on 80 Meters. The load is useless if the water boils! 73, Dr. Barry L. Ornitz WA4VZQ |
cantenna [salt water dummy loads]
On Fri, 16 Jan 2009 16:59:29 -0500, "NoSPAM"
wrote: I have done as Jim suggested when testing a kilowatt amplifier on 80 Meters. The load is useless if the water boils! Is this the dawn of another debate over power in standing waves? 73's Richard Clark, KB7QHC |
cantenna
"Jim-NN7K" . wrote in message ... One other thing might check out, is the Salt Water Dummy Loads (on several web sites). One mearly uses (can, Jar with lid), and with metal plates attached to coax connector, filled with salt water - Fill with water, then with ohm meter , add Salt until the brine hits 50 ohms! Tho, don't know how high frequency it is reliable to, should work to at least 50 MHz. Jim NN7K Generator tests (60 or 400 Hz, multi-KW) are routinely performed with a trailer-mounted device called a load bank, where plates are immersed into a tank of salt water. The depth of the plates determines the load resistance. |
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