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OK, let's discuss dipoles vs length
On 10/13/2014 4:56 PM, Lostgallifreyan wrote:
Jerry Stuckle wrote in news:m1h7sm$9bc$1@dont- email.me: I did see a video about a couple of guys free climbing an television antenna about 2K feet in the air. I lost count how many safety practices they violated. If OSHA had seen them doing that, they would have been grounded big time. The fines would have probably put the company out of business. I can't find it to check, but I do remember it being very up-front about who and where they were, and it was connected to soem company. The one I had was probably kosher enough, if was effectively a promotional video, because other, as you say, the effect would have been dramatically unwanted for them. I could be wrong, but I won't know till I find it, and I have no idea where I stowed it yet.. I don't know where it is, either - I never saved it. But AFAIK, OSHA won't take action based on a youtube video - they want to see it occurring. I could be wrong, though. However, since I don't know what the company was, there is no reasonable way to check the OSHA records (they are public). -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
"Ralph Mowery" wrote in
: Most I have climbed was 100 ft of Rohn 25. I did climb some silos at work that were about 130 feet up. Just a ladder up the side, but they did have a stepoff offset platform about every 30 feet. Axtually that I could cope with. I know what I said before about vertigo, but I have crewed on a tall ship, and I got by despite hanging over the Irish Sea in awkward coircumstances at about 60 foot up for a while, watching the sheet I'd managed to drop as it swept through the racing water below.. I just tend to freeze for a moment if overwhelmed by the insecurity of it. At moments like those I think the best thing is being able to trust the other people you're with. I'll never forget Charlie the cook on the Jean de la Lune. |
OK, let's discuss dipoles vs length
Ian Jackson wrote in
: Are you confusing the internet being carried (like cable TV) over coax at RF, and via ADSL on twisted-pair phone lines? The coax drop cables are usually RG6, which has a copper-plated steel inner. I was likely confused enough to not know what I was confusing, but I do remember it was about 40MHz or so (actually I think 36 to 39) which fits what you said below. If it's anything like some coax I worked with in the 60s, there might be a small 'kink' in the frequency response* at around 40MHz, which is probably the frequency at which all the RF has moved out of the steel core, and into the copper plating. |
OK, let's discuss dipoles vs length
On 10/13/2014 4:37 PM, Jeff Liebermann wrote:
On Mon, 13 Oct 2014 12:26:23 -0500, Lostgallifreyan wrote: If any given directional antenna can radiate at its best to one particular direction, is it safe to assume that it will be at its best similarly aimed when receiving? Yes. For purposes of calculations and under most conditions, the pattern is the same for transmit and receive for most antennas. However, there are plenty of confusing exceptions. A common exception is putting a 2.4GHz USB Wi-Fi dongle at the focus of a dish or corner reflector. The USB dongle is almost an isotropic radiator, which spews RF in all directions. If you transmit from the USB dongle, most of the RF will never hit the dish antenna and wander off to parts unknown. Only the part that hits the dish eventually ends up going towards the other end of the wireless link. However, in receive, almost all of the signal that hits the dish, gets reflected to the USB dongle. Therefore the gain is higher in receive, than in transmit. A common misconception. The radiation pattern is the same for both transmit and receive. True that most of the received signal is reflected back to the antenna. But the antenna still receives in an almost isotropic pattern, also. It has the same amount of gain in the direction of the dish in both cases. If the USB dongle were replaced with a proper dish feed, where the bulk of the transmit RF hits the dish, the dish becomes more "efficient". About 50% to 70% efficiencies are typical. However, it is also possible to mess that up in the opposite direction. Instead of a very non-directional feed, suppose I use as a feed, a high gain directional antenna with a very narrow beamwidth. Instead of spraying RF outside of the dish edge (over-spray), It puts all of it into a narrow diameter spot somewhere on the dish surface. This time, the symmetry is in the opposite direction. Transmit is fine, because all of the power produced by the feed hits the spot and is radiated in the direction of the other end of the link. However, receive is now a problem because none of the RF seen by the dish OUTSIDE the area of the spot is "seen" by the spot. Therefore, the gain is higher in transmit, than in receive. Gone to move some firewood... The same is true on receive. The dish feed also has gain, and more of the signal will be received by a proper dish feed than by an isotropic antenna. Look at it this way. The antenna is a strictly passive component. It doesn't know or care whether it is transmitting or receiving. And it doesn't care. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
Jeff Liebermann wrote in
: Yes. For purposes of calculations and under most conditions, the pattern is the same for transmit and receive for most antennas. Works for me. :) Thanks. Point taken about the other examples though, your descriptions remind me of problems with badly mismatched laser optics. Also, though I'm not sure how close this metaphor is regarding coupling efficiencies, a loudspeaker and microphone have reciprocality, as John S names it, but they have a hard time doing each other's job. (Though as a kid I preferred two small speakers and a long mains flex cable to the tin cans and string I'd read of in some book). |
OK, let's discuss dipoles vs length
Jerry Stuckle wrote in news:m1hemc$34d$2@dont-
email.me: On 10/13/2014 4:02 PM, wrote: Jerry Stuckle wrote: snip You didn't say "optimum". You said it was "crap". What part of "crap" don't you understand? I will not engage in a ****ing contest with you. You're the one who said it, not me. You think an NEC analysis is the slickest thing since snot on a doorknob. But what about HAAT or ground conductivity, for instance? What about it? Both have effects on the radiation pattern of an antenna. Feel free to include all the above in your analysis. You have considered neither when telling me my antenna was "crap" - which it provably was not. Where is the data that proves that? Easy. The QSL card from Alaska and Hawaii on 75 meters. I'm out of my depth and maybe shouldn't be posting this one, but there is a way that 'optimal' can be different in some system given a tiny modification, by example some loudspeaker tuned so it rolls off at somewhere around 80 Hz for efficiency aboive that point, then someone decides they can block the port, reduce the total drive, and lose power but gain a low of 40Hz, enough for a flat response for every string on a bass guitar. They're not the same 'optimal', but it can depend what you're after. The way I understand it, the word 'optimal' usually involves some technical tradeoff, somewhere, and there may be multiple cases that all make respectable use of calculated values.. |
OK, let's discuss dipoles vs length
Jerry Stuckle wrote:
On 10/13/2014 4:02 PM, wrote: Jerry Stuckle wrote: snip You didn't say "optimum". You said it was "crap". What part of "crap" don't you understand? I will not engage in a ****ing contest with you. You're the one who said it, not me. I will not engage in a ****ing contest with you. You think an NEC analysis is the slickest thing since snot on a doorknob. But what about HAAT or ground conductivity, for instance? What about it? Both have effects on the radiation pattern of an antenna. Yes, they do, so feel free to include all the above in your analysis. Feel free to include all the above in your analysis. You have considered neither when telling me my antenna was "crap" - which it provably was not. Where is the data that proves that? Easy. The QSL card from Alaska and Hawaii on 75 meters. ROFL. -- Jim Pennino |
OK, let's discuss dipoles vs length
On Mon, 13 Oct 2014 17:01:10 -0400, Jerry Stuckle wrote:
I don't know where it is, either - I never saved it. But AFAIK, OSHA won't take action based on a youtube video - they want to see it occurring. I could be wrong, though. However, since I don't know what the company was, there is no reasonable way to check the OSHA records (they are public). Was it this one? http://www.youtube.com/watch?v=jbEqnLjHyf8 |
OK, let's discuss dipoles vs length
Lostgallifreyan wrote:
Jerry Stuckle wrote in news:m1hemc$34d$2@dont- email.me: On 10/13/2014 4:02 PM, wrote: Jerry Stuckle wrote: snip You didn't say "optimum". You said it was "crap". What part of "crap" don't you understand? I will not engage in a ****ing contest with you. You're the one who said it, not me. You think an NEC analysis is the slickest thing since snot on a doorknob. But what about HAAT or ground conductivity, for instance? What about it? Both have effects on the radiation pattern of an antenna. Feel free to include all the above in your analysis. You have considered neither when telling me my antenna was "crap" - which it provably was not. Where is the data that proves that? Easy. The QSL card from Alaska and Hawaii on 75 meters. I'm out of my depth and maybe shouldn't be posting this one, but there is a way that 'optimal' can be different in some system given a tiny modification, by example some loudspeaker tuned so it rolls off at somewhere around 80 Hz for efficiency aboive that point, then someone decides they can block the port, reduce the total drive, and lose power but gain a low of 40Hz, enough for a flat response for every string on a bass guitar. They're not the same 'optimal', but it can depend what you're after. The way I understand it, the word 'optimal' usually involves some technical tradeoff, somewhere, and there may be multiple cases that all make respectable use of calculated values.. When I talk about an optimum antenna, I am talking about putting the maximum power in some desired direction, which may be omnidirectional or may be in some particular direction. While there are other things that can influence an antenna pattern, in reality I can not raze the houses of all the neighbors and sow the ground with salt, nor can I move my house to the top of the highest hill around. The things that are in my control are the antenna design and the height of the antenna above ground, and even that has limits. -- Jim Pennino |
OK, let's discuss dipoles vs length
I did see a video about a couple of guys free climbing an television
antenna about 2K feet in the air. I lost count how many safety practices they violated. If OSHA had seen them doing that, they would have been grounded big time. The fines would have probably put the company out of business. I can't find it to check, but I do remember it being very up-front about who and where they were, and it was connected to soem company. The one I had was probably kosher enough, if was effectively a promotional video, because other, as you say, the effect would have been dramatically unwanted for them. I could be wrong, but I won't know till I find it, and I have no idea where I stowed it yet.. If it's the one I'm thinking of (the so-called "Stairway To Heaven" video), it's all over YouTube: www.youtube.com/watch?v=MlVxRdTnNqI is one version Another tower-climbing company made the following: https://www.youtube.com/watch?v=9b9LahaBJIk which they call "Stairway To Safety", and shows a similar climb with the climbers using proper climbing-safety protocols (attached to the tower at all times). I can't find the cite at the moment, but my recollection is that both of those free-climbers lost their jobs after they posted their helmet-cam video... their employer stated that they had ignored the safety procedures required by the company. |
OK, let's discuss dipoles vs length
On 10/13/2014 6:05 PM, David Platt wrote:
I did see a video about a couple of guys free climbing an television antenna about 2K feet in the air. I lost count how many safety practices they violated. If OSHA had seen them doing that, they would have been grounded big time. The fines would have probably put the company out of business. I can't find it to check, but I do remember it being very up-front about who and where they were, and it was connected to soem company. The one I had was probably kosher enough, if was effectively a promotional video, because other, as you say, the effect would have been dramatically unwanted for them. I could be wrong, but I won't know till I find it, and I have no idea where I stowed it yet.. If it's the one I'm thinking of (the so-called "Stairway To Heaven" video), it's all over YouTube: www.youtube.com/watch?v=MlVxRdTnNqI is one version Another tower-climbing company made the following: https://www.youtube.com/watch?v=9b9LahaBJIk which they call "Stairway To Safety", and shows a similar climb with the climbers using proper climbing-safety protocols (attached to the tower at all times). I can't find the cite at the moment, but my recollection is that both of those free-climbers lost their jobs after they posted their helmet-cam video... their employer stated that they had ignored the safety procedures required by the company. Yes, that looks familiar. But notice the face of the second climber is fuzzed out so you can't identify him. I didn't listen to the audio (in bed watching TV with the XYL and she wouldn't like it :) ) so I don't know if they named the company or not. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
On 10/13/2014 6:05 PM, David Platt wrote:
I did see a video about a couple of guys free climbing an television antenna about 2K feet in the air. I lost count how many safety practices they violated. If OSHA had seen them doing that, they would have been grounded big time. The fines would have probably put the company out of business. I can't find it to check, but I do remember it being very up-front about who and where they were, and it was connected to soem company. The one I had was probably kosher enough, if was effectively a promotional video, because other, as you say, the effect would have been dramatically unwanted for them. I could be wrong, but I won't know till I find it, and I have no idea where I stowed it yet.. If it's the one I'm thinking of (the so-called "Stairway To Heaven" video), it's all over YouTube: www.youtube.com/watch?v=MlVxRdTnNqI is one version Yup, that looks like another copy of the one Radiohead posted. Another tower-climbing company made the following: https://www.youtube.com/watch?v=9b9LahaBJIk which they call "Stairway To Safety", and shows a similar climb with the climbers using proper climbing-safety protocols (attached to the tower at all times). Yes, safety takes a bit longer, but is not an option when you're more than about six feet above the ground. I can't find the cite at the moment, but my recollection is that both of those free-climbers lost their jobs after they posted their helmet-cam video... their employer stated that they had ignored the safety procedures required by the company. I'm glad to hear that. Safety procedures are there for a reason - and it's not just to prevent an OSHA fine! BTW - it is NOT required that a climber be tied off 100% of the time. It is permissible to be unattached for short periods (i.e. when climbing past guy wires). But the guys in the first video went way past what was consider a short period! -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
On 10/13/2014 5:46 PM, wrote:
Jerry Stuckle wrote: On 10/13/2014 4:02 PM, wrote: Jerry Stuckle wrote: snip You didn't say "optimum". You said it was "crap". What part of "crap" don't you understand? I will not engage in a ****ing contest with you. You're the one who said it, not me. I will not engage in a ****ing contest with you. Because you know you're full of crap. You think an NEC analysis is the slickest thing since snot on a doorknob. But what about HAAT or ground conductivity, for instance? What about it? Both have effects on the radiation pattern of an antenna. Yes, they do, so feel free to include all the above in your analysis. You made the statement - not me. Feel free to include all the above in your analysis. You have considered neither when telling me my antenna was "crap" - which it provably was not. Where is the data that proves that? Easy. The QSL card from Alaska and Hawaii on 75 meters. ROFL. So now you're calling me a liar? You, who don't even have a license and won't use your real name? You probably think 75 meters is the depth of your city swimming pool. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
Jerry Stuckle wrote:
On 10/13/2014 5:46 PM, wrote: Jerry Stuckle wrote: On 10/13/2014 4:02 PM, wrote: Jerry Stuckle wrote: snip You didn't say "optimum". You said it was "crap". What part of "crap" don't you understand? I will not engage in a ****ing contest with you. You're the one who said it, not me. I will not engage in a ****ing contest with you. Because you know you're full of crap. I will not engage in a ****ing contest with you. You think an NEC analysis is the slickest thing since snot on a doorknob. But what about HAAT or ground conductivity, for instance? What about it? Both have effects on the radiation pattern of an antenna. Yes, they do, so feel free to include all the above in your analysis. You made the statement - not me. I will not engage in a ****ing contest with you. Feel free to include all the above in your analysis. You have considered neither when telling me my antenna was "crap" - which it provably was not. Where is the data that proves that? Easy. The QSL card from Alaska and Hawaii on 75 meters. ROFL. So now you're calling me a liar? You, who don't even have a license and won't use your real name? I will not engage in a ****ing contest with you. You probably think 75 meters is the depth of your city swimming pool. I will not engage in a ****ing contest with you. -- Jim Pennino |
OK, let's discuss dipoles vs length
(David Platt) wrote in news:tuutgb-
: If it's the one I'm thinking of (the so-called "Stairway To Heaven" video), it's all over YouTube: www.youtube.com/watch?v=MlVxRdTnNqI is one version Another tower-climbing company made the following: https://www.youtube.com/watch?v=9b9LahaBJIk Having looked at them, it was probably the first one. The second one didn't exist at the time (Youtube tends to link things like this very easily when they do). I don't remember anything about a toolbag hanging from an ankle though, that sounds like a very bad idea to me. However it is managed, I'd have thought it should be attached to the strongeest, most central part of the climber, at the waist, leaving all limbs eady to move. |
OK, let's discuss dipoles vs length
Jerry Stuckle wrote in news:m1hr93$93d$1@dont-
email.me: It is permissible to be unattached for short periods (i.e. when climbing past guy wires). I wondered about that. Similar cases exist on a tall ship, there are moments where a permanent attachment would not let you pass upwards at all, but these moments are usually in structures joining sections of mast, or yards to a mast, and actually support a climber very well. |
OK, let's discuss dipoles vs length
At Mon, 13 Oct 2014 20:41:29 -0400, Jerry Stuckle rearranged some
electrons to write: You, who don't even have a license Actually he does, and I have him in my log. |
OK, let's discuss dipoles vs length
On 10/15/2014 6:12 AM, David wrote:
At Mon, 13 Oct 2014 20:41:29 -0400, Jerry Stuckle rearranged some electrons to write: You, who don't even have a license Actually he does, and I have him in my log. And of course, such a claim by an anonymous poster with an invalid email address is worth something? -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
David wrote:
At Mon, 13 Oct 2014 20:41:29 -0400, Jerry Stuckle rearranged some electrons to write: You, who don't even have a license Actually he does, and I have him in my log. It is irrelevant. I could post copies of my amateur license, old First Class license, FAA avioncs repairmans's certificate, BSEE, resume, and professional references and it would make no difference to Jerry Stuckle's attitude. While he seems to think such things are important, I am only impressed with data. -- Jim Pennino |
OK, let's discuss dipoles vs length
wrote in message ... David wrote: It is irrelevant. I could post copies of my amateur license, old First Class license, FAA avioncs repairmans's certificate, BSEE, resume, and professional references and it would make no difference to Jerry Stuckle's attitude. While he seems to think such things are important, I am only impressed with data. Most license are not worth very much. I had the first class phone when I was 22years old and had never worked on a comercial station. Probably would not know what to have done with a TV station at all. I have some refrigeration licenses that let me work with the coolant , but know very little about that. Had to get them for where I worked,but the mechanics did most of the work with the refrigerant and all I did was theelectrical part. We had a Professional Engineer (on paper anyway) where I worked ,and all he did was make a good office boy and was able to sign off on the work. I designed and installed lots of things and all he did was to take my hand drawn prints to the drafting department and the girl up there would send them back with him to make sure she put on paper what I ment for it to be. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
OK, let's discuss dipoles vs length
Ralph Mowery wrote:
wrote in message ... David wrote: It is irrelevant. I could post copies of my amateur license, old First Class license, FAA avioncs repairmans's certificate, BSEE, resume, and professional references and it would make no difference to Jerry Stuckle's attitude. While he seems to think such things are important, I am only impressed with data. Most license are not worth very much. I had the first class phone when I was 22years old and had never worked on a comercial station. Probably would not know what to have done with a TV station at all. I never worked at any broadcast station but I got the first class a couple of months before my Army discharge in the hopes that it would help me get a decent part time job when I went back to school. It did and while a second class would have been good enough for the job, the fact that I had a first clinched the deal. I have some refrigeration licenses that let me work with the coolant , but know very little about that. Had to get them for where I worked,but the mechanics did most of the work with the refrigerant and all I did was theelectrical part. We had a Professional Engineer (on paper anyway) where I worked ,and all he did was make a good office boy and was able to sign off on the work. I designed and installed lots of things and all he did was to take my hand drawn prints to the drafting department and the girl up there would send them back with him to make sure she put on paper what I ment for it to be. There was a PE at one place I worked, the bottom line to which is that I had to write an extensive SOP with mandatory design reviews for the department to keep his hair brained ideas in check. The straw that broke the camel's back was a thing that had built in self test, which was OK, but there was also self test for the self test, and self test for the self test for the self test... -- Jim Pennino |
OK, let's discuss dipoles vs length
On 10/15/2014 2:16 PM, Ralph Mowery wrote:
wrote in message ... David wrote: It is irrelevant. I could post copies of my amateur license, old First Class license, FAA avioncs repairmans's certificate, BSEE, resume, and professional references and it would make no difference to Jerry Stuckle's attitude. While he seems to think such things are important, I am only impressed with data. Most license are not worth very much. I had the first class phone when I was 22years old and had never worked on a comercial station. Probably would not know what to have done with a TV station at all. I have some refrigeration licenses that let me work with the coolant , but know very little about that. Had to get them for where I worked,but the mechanics did most of the work with the refrigerant and all I did was theelectrical part. Interesting. I got my First Class at 18, and at 19 I was chief engineer at the campus radio station. Sure, only 10W FM (and carrier current AM to the dorms). By 25 I had worked at three other stations part time. Didn't get my Extra until I was 19 - that two year waiting period got me. But probably a good thing - I found the Extra test to be harder than either First or Second phone. -- ================== Remove the "x" from my email address Jerry Stuckle ================== |
OK, let's discuss dipoles vs length
At Wed, 15 Oct 2014 06:23:33 -0400, Jerry Stuckle rearranged some
electrons to write: On 10/15/2014 6:12 AM, David wrote: At Mon, 13 Oct 2014 20:41:29 -0400, Jerry Stuckle rearranged some electrons to write: You, who don't even have a license Actually he does, and I have him in my log. And of course, such a claim by an anonymous poster with an invalid email address is worth something? And of course, your opinion is unimportant to me. |
OK, let's discuss dipoles vs length
On 10/15/2014 10:05 PM, David wrote:
At Wed, 15 Oct 2014 06:23:33 -0400, Jerry Stuckle rearranged some electrons to write: On 10/15/2014 6:12 AM, David wrote: At Mon, 13 Oct 2014 20:41:29 -0400, Jerry Stuckle rearranged some electrons to write: You, who don't even have a license Actually he does, and I have him in my log. And of course, such a claim by an anonymous poster with an invalid email address is worth something? And of course, your opinion is unimportant to me. As if I care - NOT! Anonymous trolls like you are of no importance. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
OK, let's discuss dipoles vs length
On Wed, 15 Oct 2014 18:30:46 -0000, wrote:
The straw that broke the camel's back was a thing that had built in self test, which was OK, but there was also self test for the self test, and self test for the self test for the self test... Chuckle. I had much the same problem except that the self test function was aptly named BITE (Built In Test Equipment). All too often, the radio would be fully functional, but the system would be down because the BITE was complaining about something spurious. Someone suggested a second BITE to monitor the first. That was prototyped by some other engineer, which further reduced the reliability of the system. Eventually, I was handed the mess, with instructions not to spend any money, not to change anything, and get it done before my boss returned from vacation (so he couldn't be blamed if anything went wrong). My solution was to redesign the interface between the radio and the BITE so that the BITE boards could be removed without affecting the operation of the radio. The result was predictable. All the BITE boards were immediately removed on arrival by the customer, thrown into an unmarked cardboard box, and left to rot while the radios continued to operate normally without them. Morals: Complexity does not improve reliability and the first thing to fail is usually the fail safe. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
OK, let's discuss dipoles vs length
On Wed, 15 Oct 2014 15:28:41 -0400, Jerry Stuckle
wrote: Interesting. I got my First Class at 18, and at 19 I was chief engineer at the campus radio station. Sure, only 10W FM (and carrier current AM to the dorms). By 25 I had worked at three other stations part time. Didn't get my Extra until I was 19 - that two year waiting period got me. But probably a good thing - I found the Extra test to be harder than either First or Second phone. The subject of licenses appeared in rec.radio.amateur.moderated about two weeks ago. This is a copy of what I posted: You might be amused at how I obtained my extra class ticket. I had been a tech since the 1960's and saw no reason to learn Morse code in order to talk on HF. I was working for various 2way and marine radio companies. The last thing I wanted to do when I left work was see another radio. I almost let my tech license lapse, but a friend shoved the 610 form in my face and demanded that I renew. When the code requirement was finally dropped for general class I decided it was time to upgrade. Having passed the tech exam in the dark ages (tubes, dynamotors, and Marconi antennas) was deemed sufficient to demonstrate my technical competence. Therefore, I was not required to repeat the exam. The procedure required that I find all my old FCC licenses, which amazingly were exactly where I buried them. When I appeared at the scheduled VEC exam, I was informed that for the same price ($10), I could take the extra exam. If I failed, then they would grant me a general class license as a consolation prize. Just one problem. I hadn't studied at all for the extra exam. I sat down with a borrowed calculator and began to sweat my way through the questions. The technical questions were easy. The questions on HF operating protocol, band limits, and procedures were unfathomable, so I resorted to guessing. I'm fairly sure that I got all the technical questions right, and missed most of the operational questions. I was later informed that I had passed by one question. Whew. Unfortunately, one of my friends surpassed my feat. He became tired of using his foreign call sign and decided to get a US ham license. He passed all 4 elements in one sitting, without missing a single question, and possibly without studying. I was crushed but still offered my congratulations. I don't recommend attempting the extra class exam totally unprepared. However, if anyone asks, it can be passed without studying. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
OK, let's discuss dipoles vs length
Jeff Liebermann wrote in
: All too often, the radio would be fully functional, but the system would be down because the BITE was complaining about something spurious. Someone suggested a second BITE to monitor the first. The devil drives a fine wedge. :) What I do in this case is let the thing pass with a warning to the user. What they make of it is up to them, but it is ALWAYS best to have the machine surrender control if in doubt, because the alternative is to ALWAYS leave a person wondering exactly where something first appeard to go wrong, simple because it did NOT appear. A dumb human can usually do more than a smart but broken machine. |
OK, let's discuss dipoles vs length
Jeff Liebermann wrote in
: Morals: Complexity does not improve reliability and the first thing to fail is usually the fail safe. Spot on. |
OK, let's discuss dipoles vs length
On Thu, 16 Oct 2014 02:36:44 -0500, Lostgallifreyan
wrote: Jeff Liebermann wrote in : All too often, the radio would be fully functional, but the system would be down because the BITE was complaining about something spurious. Someone suggested a second BITE to monitor the first. The devil drives a fine wedge. :) I am the devil, or at least some of my friends and customers think I am. (The difference between a friend and a customer is the customers pay me, while the friends do not). What I do in this case is let the thing pass with a warning to the user. What they make of it is up to them, but it is ALWAYS best to have the machine surrender control if in doubt, because the alternative is to ALWAYS leave a person wondering exactly where something first appeard to go wrong, simple because it did NOT appear. A dumb human can usually do more than a smart but broken machine. That would not work for this situation. The end user was the USCG (United States Coast Guard). Average age of the users is about 17 or 18 years old. Specifications were to not let anyone make a decision beyond looking for a red light on top of the PCB, and replace whatever lights up red. I looked back at my troubleshooting abilities (mostly automotive) when I was their age, and decided that it was the best philosophy. Somewhat later, I visited the USCG depot level repair shop on Treasure Island in the middle of San Francisco Bay. The techs there were better qualified, but still mystified if replacing a board did not magically solve a problem. During the tour of the facility, I was shown the "bone pile", which was a rather large collection of radios used for spare parts. I did some quick math and estimated that it contained about 2% of the radios we sold to the USCG. The BITE boards were not totally wasted. I showed them how to use them as a troubleshooting and testing aid for bench testing. With some help, I was able to diagnose about 15 radios and fix 10 of them using the BITE boards, which demonstrated that they were not a total wasted. Every test bench soon had a set of BITE boards. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
OK, let's discuss dipoles vs length
Jeff Liebermann wrote in
: That would not work for this situation. The end user was the USCG (United States Coast Guard). Average age of the users is about 17 or 18 years old. Specifications were to not let anyone make a decision beyond looking for a red light on top of the PCB, and replace whatever lights up red. I looked back at my troubleshooting abilities (mostly automotive) when I was their age, and decided that it was the best philosophy. FOr sure, if it's mission critical. My code isn't, except to me. :) TO be more precise, what I do is (for example) load some synth patch, and if the checksum fails I let it pass with a warning, but I do not force the user to make a difficult (or any) choice. Instead, it seems better to assume that the source data might be useable and process as best I can. The user will know the checksum failed, but if in doubt the instrument will have handled the incoming data as best possible without the user having to do anything. In this context it makes best sense because 'the show must go on' in any live use of the system, and a sound that is close is better than no sound at all. Ideally the user will have a backup and when they see my equivalent of your red light, they'll use it. :) |
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