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When did ignorance overcome education, for the correct plural is, "antennae"?
In article , rickman
wrote: What is wrong with pacemakers that they can't make one that functions around radios and microwaves? They can and do, for most situations. But an end-fed antenna will have common mode currents and I'd just as soon not have such flowing in my pacemaker wiring. My pacemaker is located just to the right of, and below, my left shoulder. There are two wires leading out of it which go to my right atrium and right ventricle. These wires bring signals up from the heart to the pacemaker telling the pacemaker when the heart is beating, and, when necessary, take much stronger signals down from the pacemaker to the heart to get it to behave correctly if it is not doing so. There must in effect also be a "ground" connection with the metallic pacemaker case embedded in tissue in front of my ribs. Common mode current from an unbalanced antenna sysem flowing in my body might do the pacemaker no good. I'd just as soon not find that out 10 miles from a trailhead. So I use balanced antennas, balanced feedline, and a good 1:1 current balun at the bottom of the feedline. The tuner inside my KX3 then makes the KX3 final amplifier happy. I have also used a coax-fed balanced antenna with balun at the antenna feedpoint, but a doublet with open-wire feedline and balun at the bottom is a better multi-band solution. Magnetic fields are also bad for pacemakers. When my cardiologist tests things he brings a magnet close to my chest while monitoring the pacemaker performance. This is done in a controlled way with observation of the effect. I have been warned that high intensity magnetic fields are very dangerous. At airports I present a card indicating I have a pacemaker, and I get gone over by hand instead of magnetically. I definiely don't put my iPod earbuds in my shirt pocket! The iPod itself is often placed there when I use it while walking or hiking. I have been warned that I must never have an MRI done on me. There is no reason to believe that the very low power cordless phones used with our landline telephone, or cell phones, pose a problem. The magents in them are up by my ear, not near the pacemaker, and aren't all that strong. The electromagnetic fields aren't all that strong either. But consider how much RF current flows, especially in a low-resistance high-reactance short unbalanced antenna, even at QRP levels. That's why I want what comes out of my KX3 to be radiated and do some good, not generate common mode current that may make my pacemaker, and then me, unhappy. Maybe I'm being too cautious. But better safe than sorry. And anyway, I suspect my balanced doublet fed with open wire is a lot more efficient than the typical random length end-fed wire connected to a transmitter through a possibly very lossy Unun. It does require two trees, unless erected as an inverted V, whereas an end-fed wire gets by with one. Doing it the safer way is correct from an engineering standpoint too. It would be a shame if one had to choose between efficiency and safety. David, VE7EZM and AF7BZ -- David Ryeburn To send e-mail, change "netz" to "net" |
When did ignorance overcome education, for the correct plural is,"antennae"?
On 5/24/2016 1:05 AM, wrote:
rickman wrote: On 5/23/2016 9:08 PM, wrote: rickman wrote: On 5/23/2016 6:52 PM, wrote: rickman wrote: On 5/23/2016 6:05 PM, David Ryeburn wrote: I've kind of liked end-fed wires as antennas ever since, though now I'm well aware of their limitations, and, with a pacemaker inside me, I no longer dare use one. Balanced lines and center-fed doublets are a nuisance when you go backpacking, but I do want to be able to hike back out to the car afterwards. What is wrong with pacemakers that they can't make one that functions around radios and microwaves? Lack of space for installing the faraday cage. Pacemakers DO function around radios and microwaves. http://www.heart.org/HEARTORG/Condit...13_Article.jsp Lol! Devices that have to work should be designed to work properly in the very low level fields that occur in every day life. It's not really hard. There are any number of engineers who can do that. According to the article, they ARE designed to work properly in the very low level fields that occur in everyday life and the biggest risks are from medical equipment. Your reference contradicts what you say. Are MP3 players "medical" equipment? What part of the word 'biggest' did you fail to understand? Exactly. You didn't really say anything since you qualify it so it means nothing. Bottom line is pacemakers have problems with common household electronics. Not well designed I think. -- Rick C |
When did ignorance overcome education, for the correct plural is, "antennae"?
rickman wrote:
On 5/24/2016 1:05 AM, wrote: rickman wrote: On 5/23/2016 9:08 PM, wrote: rickman wrote: On 5/23/2016 6:52 PM, wrote: rickman wrote: On 5/23/2016 6:05 PM, David Ryeburn wrote: I've kind of liked end-fed wires as antennas ever since, though now I'm well aware of their limitations, and, with a pacemaker inside me, I no longer dare use one. Balanced lines and center-fed doublets are a nuisance when you go backpacking, but I do want to be able to hike back out to the car afterwards. What is wrong with pacemakers that they can't make one that functions around radios and microwaves? Lack of space for installing the faraday cage. Pacemakers DO function around radios and microwaves. http://www.heart.org/HEARTORG/Condit...ventionTreatme ntofArrhythmia/Devices-that-may-Interfere-with-Pacemakers_UCM_302013_ Article.jsp Lol! Devices that have to work should be designed to work properly in the very low level fields that occur in every day life. It's not really hard. There are any number of engineers who can do that. According to the article, they ARE designed to work properly in the very low level fields that occur in everyday life and the biggest risks are from medical equipment. Your reference contradicts what you say. Are MP3 players "medical" equipment? What part of the word 'biggest' did you fail to understand? Exactly. You didn't really say anything since you qualify it so it means nothing. Bottom line is pacemakers have problems with common household electronics. Not well designed I think. i think it is more that pacemakers *could* potentially have problems with everyday equipment under worst-case scenarios, especially with possible faults. They don't usually, but for obvious reasons even rare and unlikely risks have to be considered. -- Roger Hayter |
When did ignorance overcome education, for the correct plural is, "antennae"?
On Mon, 23 May 2016 20:20:29 -0400, rickman wrote:
Here's the list from your reference. Notice that even MP3 players with earbuds are a risk! The risk is not so much any RF but rather from magnetic fields. All the items on your list have magnets somewhere. MP3 player ear bugs are a good start. Magnets are used to program and control a pacemaker. A friend managed to make a mess of his pacemaker programming with an electric drill motor. https://www.google.com/#q=pacemaker+magnets As for RF shielding: "Shielded pacemaker enclosure" http://www.google.com/patents/US5895980 See citations for more. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
When did ignorance overcome education, for the correct plural is, "antennae"?
rickman wrote:
On 5/24/2016 1:05 AM, wrote: rickman wrote: On 5/23/2016 9:08 PM, wrote: rickman wrote: On 5/23/2016 6:52 PM, wrote: rickman wrote: On 5/23/2016 6:05 PM, David Ryeburn wrote: I've kind of liked end-fed wires as antennas ever since, though now I'm well aware of their limitations, and, with a pacemaker inside me, I no longer dare use one. Balanced lines and center-fed doublets are a nuisance when you go backpacking, but I do want to be able to hike back out to the car afterwards. What is wrong with pacemakers that they can't make one that functions around radios and microwaves? Lack of space for installing the faraday cage. Pacemakers DO function around radios and microwaves. http://www.heart.org/HEARTORG/Condit...13_Article.jsp Lol! Devices that have to work should be designed to work properly in the very low level fields that occur in every day life. It's not really hard. There are any number of engineers who can do that. According to the article, they ARE designed to work properly in the very low level fields that occur in everyday life and the biggest risks are from medical equipment. Your reference contradicts what you say. Are MP3 players "medical" equipment? What part of the word 'biggest' did you fail to understand? Exactly. You didn't really say anything since you qualify it so it means nothing. Bottom line is pacemakers have problems with common household electronics. Not well designed I think. Whatever. -- Jim Pennino |
When did ignorance overcome education, for the correct pluralis, "antennae"?
On Thu, 19 May 2016 11:07:03 -0700, Mike Ross wrote:
On Thursday, October 8, 2015 at 8:28:38 AM UTC-4, gareth wrote: "joe" wrote in message ... gareth wrote: I have in my possession a book entitled, "Antennae", published in 1942 by a lecturer to both King's College, London, and also to various Brit government establishments. At some point since then, the ignorance of either engineers or of Yanks has tried to pass off, "Antennas" as the plural. If we pride ourselves on the exactness of our principles, then it is high time to correct this glaring error by the Yanks. (Book being studied avidly, although with some necessary revision ov vector field theory; div, curl and grad, anyone?) From an online dictionary: I guess that it would be a fair assumption, bearing in mind the development of computers and, much later, the Internet, that your online dictionaries originated several decades after 1942, and long after the ignoramuses' error arose? Um, wouldn't that be "ignorami"?? Clearly the attempt of a person lacking even the most elemental education in the classics. The Latin word ignoramus is not a noun, and so cannot be declined. Even if it were, its genitive plural is somthing quite different. -- Suspect someone is claiming a benefit under false pretences? Incapacity Benefit or Personal Independence Payment when they don't need it? They are depriving those in real need! https://www.gov.uk/report-benefit-fraud |
When did ignorance overcome education, for the correct pluralis, "antennae"?
On Sun, 31 Jul 2016 21:34:44 +0000 (UTC), Brian Reay wrote:
On Thu, 19 May 2016 11:07:03 -0700, Mike Ross wrote: On Thursday, October 8, 2015 at 8:28:38 AM UTC-4, gareth wrote: "joe" wrote: gareth wrote: I have in my possession a book entitled, "Antennae", published in 1942 by a lecturer to both King's College, London, and also to various Brit government establishments. At some point since then, the ignorance of either engineers or of Yanks has tried to pass off, "Antennas" as the plural. If we pride ourselves on the exactness of our principles, then it is high time to correct this glaring error by the Yanks. (Book being studied avidly, although with some necessary revision ov vector field theory; div, curl and grad, anyone?) From an online dictionary: I guess that it would be a fair assumption, bearing in mind the development of computers and, much later, the Internet, that your online dictionaries originated several decades after 1942, and long after the ignoramuses' error arose? Um, wouldn't that be "ignorami"?? Clearly the attempt of a person lacking even the most elemental education in the classics. The Latin word ignoramus is not a noun, and so cannot be declined. Even if it were, its genitive plural is somthing quite different. Please, God, let this thread die! |
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