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#121
October 18th 18, 05:48 PM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
On Thu, 18 Oct 2018 14:32:01 +0100, Custos Custodum
wrote: On Wed, 17 Oct 2018 17:01:33 -0700, Jeff Liebermann wrote: On Wed, 17 Oct 2018 20:55:22 +0100, Custos Custodum wrote: On Wed, 17 Oct 2018 08:00:55 -0700, Jeff Liebermann wrote: Much of the stuff I fix was sent to me after some ham attempted to fix it themselves. Usually, they won't admit it. On the repair bench right now is an Astron power supply, an MFJ-259 antenna analyzer, two HP5300 series counters, Which ones, if you don't mind my asking? (...) Looking around the shop, there's quite a bit of additional test equipment that could use my attention. Most of it is not worth the time but I do it anyway. For example, three sweep generators: http://www.learnbydestroying.com/jeffl/pics/home/slides/BL-shop5.html There also a bunch of big linear power supplies that probably need new electrolytics. My IFR-1500 has a blown power supply that I can't seem to fix. I thought I had it fixed in 2010, but it died again in 2015: http://www.learnbydestroying.com/jeffl/IFR-1500%20Power%20Supply%20Repair/IFR-1500%20power%20supply%20repair.html Does that answer your question? Yes, thanks. I was curious about the counters as I have some post-design experience of some of the later models in that range, but yours were a bit before my time (mid-70s, IIRC). I might have been able to help you out with hard-to-get parts. Thank you for the offer, but right now, all the counters need are some new knobs, caps, and contact cleaner. I can handle those. Also, this was not a critical repair. The "customer" is one of the local hams who wanted a "real" counter/timer so he could set the timing on some mechanical contraption he's building. I had done quite a bit of that with the various counters in the distant past, so I offered to give him one of mine. That's when I discovered that all of them had problems. So, I gave him a much better HP5315A 100MHz counter yesterday. He's happy. I'm looking at the 1980 HP buyers guide which shows what looks like the entire HP5300A/B counter system and plugins. No date showing but it certainly was before 1980. I couldn't find any printed manuals from which to extract a date. I was using them starting in about 1973, but I'm certain they were around a few years before that. Ah, just found the 1977 buyers guide. All of the HP5300A/B plugins are present and accounted for. Early 1970's seems correct. Thanks again. -- 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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#122
October 18th 18, 06:01 PM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
On Thu, 18 Oct 2018 08:09:01 +0000, Spike
wrote: On 18/10/2018 01:35, Jeff Liebermann wrote: diversion into a side-topic snipped It wasn't a diversion, but if you don't want to discuss it, that's fine. If you have an allergy or an aversion to numbers, that's also fine. I'll try not to mention any numbers if you feel threatened. Fear of numbers (numerophobia or arithmophobia) is amazingly common these days as we transition from an analog world to a digital world. Usually, it is fear of some specific number that causes a problem. However, there are individuals, such as politicians, who fear all numbers. These might help: https://www.fearof.net/fear-of-numbers-phobia-numerophobia-or-arithmophobia/ "How To Overcome Fear Of Numbers" https://www.youtube.com/watch?v=OKPaeb6nmsw (2:00) So, how do you make an RF tuning light bulb produce numbers? A light meter? By calculation, old boy, by calculation. Don't you do calculations in the US? Well, last time I checked, calculations are done using numbers. What numbers are you using to calculate and how did you conjur them? Do your light bulbs include a brightness indicator? -- 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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#123
October 18th 18, 07:22 PM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
Jeff Liebermann wrote:
On Thu, 18 Oct 2018 08:09:01 +0000, Spike wrote: On 18/10/2018 01:35, Jeff Liebermann wrote: diversion into a side-topic snipped It wasn't a diversion, but if you don't want to discuss it, that's fine. If you have an allergy or an aversion to numbers, that's also fine. I'll try not to mention any numbers if you feel threatened. Fear of numbers (numerophobia or arithmophobia) is amazingly common these days as we transition from an analog world to a digital world. Usually, it is fear of some specific number that causes a problem. However, there are individuals, such as politicians, who fear all numbers. These might help: https://www.fearof.net/fear-of-numbers-phobia-numerophobia-or-arithmophobia/ "How To Overcome Fear Of Numbers" https://www.youtube.com/watch?v=OKPaeb6nmsw (2:00) So, how do you make an RF tuning light bulb produce numbers? A light meter? By calculation, old boy, by calculation. Don't you do calculations in the US? Well, last time I checked, calculations are done using numbers. What numbers are you using to calculate and how did you conjur them? Do your light bulbs include a brightness indicator? You can compare the brightness of two similar lightbulbs with a moderate amount of precision. You just have to take care that the bulb is not changing the thing you're measuring too much. -- Roger Hayter |
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#125
October 18th 18, 08:12 PM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
Jeff Liebermann wrote:
On Thu, 18 Oct 2018 19:22:02 +0100, (Roger Hayter) wrote: Jeff Liebermann wrote: On Thu, 18 Oct 2018 08:09:01 +0000, Spike wrote: On 18/10/2018 01:35, Jeff Liebermann wrote: diversion into a side-topic snipped It wasn't a diversion, but if you don't want to discuss it, that's fine. If you have an allergy or an aversion to numbers, that's also fine. I'll try not to mention any numbers if you feel threatened. Fear of numbers (numerophobia or arithmophobia) is amazingly common these days as we transition from an analog world to a digital world. Usually, it is fear of some specific number that causes a problem. However, there are individuals, such as politicians, who fear all numbers. These might help: https://www.fearof.net/fear-of-numbe...ia-or-arithmop hobia/ "How To Overcome Fear Of Numbers" https://www.youtube.com/watch?v=OKPaeb6nmsw (2:00) So, how do you make an RF tuning light bulb produce numbers? A light meter? By calculation, old boy, by calculation. Don't you do calculations in the US? Well, last time I checked, calculations are done using numbers. What numbers are you using to calculate and how did you conjur them? Do your light bulbs include a brightness indicator? You can compare the brightness of two similar lightbulbs with a moderate amount of precision. You just have to take care that the bulb is not changing the thing you're measuring too much. Sure. The standard candle used to measure the distance to a star in astronomy is such a measurement. The problem is that the standard candle is great for comparison measurements, it much also be calibrated against a known illumination source. Finding a light bulb with a known specific brightness and suitable for making a comparison does not seem very easy. Same with "similar" light bulbs. One would still need to calibrate the standard light bulb in some manner. Might as well use a lux meter. "Standard candles" http://www.astro.ex.ac.uk/people/hatchell/rinr/candles.pdf Note that I'm ignoring the change in filament resistance at different illumination levels with adds some unwanted non-linearity to the light bulb power measurement. You don't have to measure the brightness, you just alter and measure the DC power to one bulb while comparing it with the RF illuminated one. -- Roger Hayter |
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#126
October 19th 18, 07:15 AM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
On Thu, 18 Oct 2018 20:12:55 +0100, (Roger Hayter)
wrote: Jeff Liebermann wrote: On Thu, 18 Oct 2018 19:22:02 +0100, (Roger Hayter) wrote: Jeff Liebermann wrote: On Thu, 18 Oct 2018 08:09:01 +0000, Spike wrote: On 18/10/2018 01:35, Jeff Liebermann wrote: diversion into a side-topic snipped It wasn't a diversion, but if you don't want to discuss it, that's fine. If you have an allergy or an aversion to numbers, that's also fine. I'll try not to mention any numbers if you feel threatened. Fear of numbers (numerophobia or arithmophobia) is amazingly common these days as we transition from an analog world to a digital world. Usually, it is fear of some specific number that causes a problem. However, there are individuals, such as politicians, who fear all numbers. These might help: https://www.fearof.net/fear-of-numbe...ia-or-arithmop hobia/ "How To Overcome Fear Of Numbers" https://www.youtube.com/watch?v=OKPaeb6nmsw (2:00) So, how do you make an RF tuning light bulb produce numbers? A light meter? By calculation, old boy, by calculation. Don't you do calculations in the US? Well, last time I checked, calculations are done using numbers. What numbers are you using to calculate and how did you conjur them? Do your light bulbs include a brightness indicator? You can compare the brightness of two similar lightbulbs with a moderate amount of precision. You just have to take care that the bulb is not changing the thing you're measuring too much. Sure. The standard candle used to measure the distance to a star in astronomy is such a measurement. The problem is that the standard candle is great for comparison measurements, it much also be calibrated against a known illumination source. Finding a light bulb with a known specific brightness and suitable for making a comparison does not seem very easy. Same with "similar" light bulbs. One would still need to calibrate the standard light bulb in some manner. Might as well use a lux meter. "Standard candles" http://www.astro.ex.ac.uk/people/hatchell/rinr/candles.pdf Note that I'm ignoring the change in filament resistance at different illumination levels with adds some unwanted non-linearity to the light bulb power measurement. You don't have to measure the brightness, you just alter and measure the DC power to one bulb while comparing it with the RF illuminated one. Yes, that will work but will provide only a single value of RF power that corresponds to a single value of brightness. It's also not the way the "standard candle" works. In the standard candle, there's no assumption that the brightness of the reference light and the measured light will be equal. Instead, it relies on inverse square law which basically states that if you move a light bulb twice as far away, it will be 1/4th as bright. Move it 3 times as far away, and it's 1/9th as bright. And so on. Let's start with an RF powered light at some brightness level. Next to it, I take a brighter bulb, where I know the brightness. This light is NOT adjustable and is always the same known brightness. Now, I move this bulb farther away until it appears to be exactly the same brightness as the RF powered light bulb. At this point, I know: 1. The distance between the observer (me) and the RF powered light bulb which I'll call A. 2. The distance between the observer (me) and the reference light bulb which I'll call B. 3. The brightness of the reference light bulb which I'll call C. 4. I'll call the unknown brightness of the RF powered bulb as D. Let's say that the observer is 2 meters away from the RF powered light, and that the reference light is the same brightness as the RF powered light at a distance of 5 meters. I'll assume the reference light produced 1000 lux. Therefore, the brightness of the RF powered light is: 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Presumably, the reference light was calibrated for brightness at a given RF level. Let's say it's 50 watts for 1000 lux. Therefore, the RF power of the RF powered light would be: 632 / 1000 * 50 = 32 watts Again, notice that I don't need an adjustable reference light, I don't need a corresponding lux-watts calibration chart, and that there no inconvenient non-linearities involved due to variations in filament resistance. -- 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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#127
October 22nd 18, 12:21 PM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
On 17/10/2018 16:12, Jeff Liebermann wrote:
On Wed, 17 Oct 2018 10:36:45 +0000, Spike wrote: That's the sort of road that Liebermann wanted to take the discussion down; an interesting topic but not the issue under discussion. Guilty as charged. I do tend to divert discussions in directions that I find interesting. After all, why bother writing a long rant that nobody will read? One-line pontifications, or the all too common SMS/chat messaging method of discussion are terminally boring, and rarely produce anything worth reading. The lack of substantiation, references, and detail found in such short comments offer little in the way of an education, unless refining one's skill at delivering insults is considered educational. I've tried to adopt a policy of only writing and posting things that I think might be worth reading. That which is unlikely to be of general interest, I don't bother posting. If everyone followed such a policy, the various newsgroups would be much more pleasant and interesting to read. ======= +1 Frank EI7KS |
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#128
October 23rd 18, 11:05 PM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
On 19/10/2018 06:15, Jeff Liebermann wrote:
Spike contended that a distant station cannot tell the difference between a sending station that has been tuned up using a torch bulb and one that has used an expensive VNA for that purpose. Via some other topics, the discussion on the torch bulb vs VNA issue has now reached this point: Let's start with an RF powered light at some brightness level. Next to it, I take a brighter bulb, where I know the brightness. This light is NOT adjustable and is always the same known brightness. Now, I move this bulb farther away until it appears to be exactly the same brightness as the RF powered light bulb. At this point, I know: 1. The distance between the observer (me) and the RF powered light bulb which I'll call A. 2. The distance between the observer (me) and the reference light bulb which I'll call B. 3. The brightness of the reference light bulb which I'll call C. 4. I'll call the unknown brightness of the RF powered bulb as D. Let's say that the observer is 2 meters away from the RF powered light, and that the reference light is the same brightness as the RF powered light at a distance of 5 meters. I'll assume the reference light produced 1000 lux. Therefore, the brightness of the RF powered light is: 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Presumably, the reference light was calibrated for brightness at a given RF level. Let's say it's 50 watts for 1000 lux. Therefore, the RF power of the RF powered light would be: 632 / 1000 * 50 = 32 watts A lamp of power or light output P has a light intensity at a point at a distance r from it that is a function of P/4pi*r^2 Two lamps of differing power or light output, P1 and P2, and spaced apart will have a point somewhere between them where the light intensities are equal. At this point the distance from P1 to the point of equal intensity is given by r1, and for P2 that distance is r2 and we thus have the equality given by: P1/(4pi*r1^2) = P2/(4pi*r2^2) Simplifying: P1/r1^2 = P2/r2^2 From which it can be seen that, if the power or light output of P1 is known then: P2 = P1(r2^2)/(r1^2) If P1 = 50 units of power or light output, and r1 and r2 are 5 and 2 units of distance respectively then: P2 = 50 * 2^2/5^2 = 50 * 4/25 = 8 units of power or light output, Now take your equation above: 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Using my notation as above, this becomes P1/((r1/r2)^0.5) = P2 Rearranging this and separating the terms gives P1/(r1)^0.5 = P2/(r2)^0.5 You seem to have invented the Lieberman Law of Inverse Square Roots... HTH -- Spike "Nearly all men can stand adversity, but if you want to test a man's character, give him an internet group to manage" |
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#129
October 24th 18, 08:35 AM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
In message , Spike
writes On 19/10/2018 06:15, Jeff Liebermann wrote: Spike contended that a distant station cannot tell the difference between a sending station that has been tuned up using a torch bulb and one that has used an expensive VNA for that purpose. Via some other topics, the discussion on the torch bulb vs VNA issue has now reached this point: Let's start with an RF powered light at some brightness level. Next to it, I take a brighter bulb, where I know the brightness. This light is NOT adjustable and is always the same known brightness. Now, I move this bulb farther away until it appears to be exactly the same brightness as the RF powered light bulb. At this point, I know: 1. The distance between the observer (me) and the RF powered light bulb which I'll call A. 2. The distance between the observer (me) and the reference light bulb which I'll call B. 3. The brightness of the reference light bulb which I'll call C. 4. I'll call the unknown brightness of the RF powered bulb as D. Let's say that the observer is 2 meters away from the RF powered light, and that the reference light is the same brightness as the RF powered light at a distance of 5 meters. I'll assume the reference light produced 1000 lux. Therefore, the brightness of the RF powered light is: 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Presumably, the reference light was calibrated for brightness at a given RF level. Let's say it's 50 watts for 1000 lux. Therefore, the RF power of the RF powered light would be: 632 / 1000 * 50 = 32 watts A lamp of power or light output P has a light intensity at a point at a distance r from it that is a function of P/4pi*r^2 Two lamps of differing power or light output, P1 and P2, and spaced apart will have a point somewhere between them where the light intensities are equal. At this point the distance from P1 to the point of equal intensity is given by r1, and for P2 that distance is r2 and we thus have the equality given by: P1/(4pi*r1^2) = P2/(4pi*r2^2) Simplifying: P1/r1^2 = P2/r2^2 From which it can be seen that, if the power or light output of P1 is known then: P2 = P1(r2^2)/(r1^2) If P1 = 50 units of power or light output, and r1 and r2 are 5 and 2 units of distance respectively then: P2 = 50 * 2^2/5^2 = 50 * 4/25 = 8 units of power or light output, Now take your equation above: 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Using my notation as above, this becomes P1/((r1/r2)^0.5) = P2 Rearranging this and separating the terms gives P1/(r1)^0.5 = P2/(r2)^0.5 You seem to have invented the Lieberman Law of Inverse Square Roots... If you're using incandescent bulbs , the two bulbs have different colour temperatures . The dimmer one radiates more power in the red and infra red or "heat bands" My good friend Mr Planck sussed this out. If you try to use your eyes to judge brightness, the human eye spectral response causes the redder one to look disproportionally dimmer. I've had these sort of problems trying to simulate sunlight using tungsten lamps. There's a further problem introduced by the area of the lamp, which bu@@ers up the inverse square law. You might not have that problem with a "pea" bulb. Brian -- Brian Howie |
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#130
October 24th 18, 10:27 AM
posted to uk.radio.amateur,rec.radio.amateur.antenna
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4NEC2?
On 24/10/2018 08:35, brian wrote:
In message , Spike writes On 19/10/2018 06:15, Jeff Liebermann wrote: Spike contended that a distant station cannot tell the difference between a sending station that has been tuned up using a torch bulb and one that has used an expensive VNA for that purpose. Via some other topics, the discussion on the torch bulb vs VNA issue has now reached this point: Let's start with an RF powered light at some brightness level.Â* Next to it, I take a brighter bulb, where I know the brightness.Â* This light is NOT adjustable and is always the same known brightness.Â* Now, I move this bulb farther away until it appears to be exactly the same brightness as the RF powered light bulb.Â* At this point, I know: 1.Â* The distance between the observer (me) and the RF powered light bulb which I'll call A. 2.Â* The distance between the observer (me) and the reference light bulb which I'll call B. 3.Â* The brightness of the reference light bulb which I'll call C. 4.Â* I'll call the unknown brightness of the RF powered bulb as D. Let's say that the observer is 2 meters away from the RF powered light, and that the reference light is the same brightness as the RF powered light at a distance of 5 meters.Â* I'll assume the reference light produced 1000 lux.Â* Therefore, the brightness of the RF powered light is: Â*Â* 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Presumably, the reference light was calibrated for brightness at a given RF level.Â* Let's say it's 50 watts for 1000 lux.Â* Therefore, the RF power of the RF powered light would be: Â*Â* 632 / 1000 * 50 = 32 watts A lamp of power or light output P has a light intensity at a point at a distance r from it that is a function of P/4pi*r^2 Two lamps of differing power or light output, P1 and P2, and spaced apart will have a point somewhere between them where the light intensities are equal. At this point the distance from P1 to the point of equal intensity is given by r1, and for P2 that distance is r2 and we thus have the equality given by: P1/(4pi*r1^2) = P2/(4pi*r2^2) Simplifying: P1/r1^2 = P2/r2^2 From which it can be seen that, if the power or light output of P1 is known then: P2 = P1(r2^2)/(r1^2) If P1 = 50 units of power or light output, and r1 and r2 are 5 and 2 units of distance respectively then: P2 = 50 * 2^2/5^2 = 50 * 4/25 = 8 units of power or light output, Now take your equationÂ* above: 1000 / (5/2)^0.5 = 1000 / 1.58 = 632 lux Using my notation as above, this becomes P1/((r1/r2)^0.5) = P2 Rearranging this and separating the terms gives P1/(r1)^0.5 = P2/(r2)^0.5 You seem to have invented the Lieberman Law of Inverse Square Roots... If you're using incandescentÂ* bulbs , the two bulbs have different colour temperatures . The dimmer one radiates more power in the red and infra red or "heat bands" My good friend Mr Planck sussed this out. If you try to use your eyes to judge brightness, the human eye spectral response causes the redder one to look disproportionally dimmer. I've had these sort of problems trying to simulate sunlight using tungsten lamps. There's a further problem introduced by the area of the lamp, which bu@@ers up the inverse square law. You might not have that problem with a "pea" bulb. Spike has enough rope to play with already. Jeff, like myself, tends to give idiots just enough to hang themselves. He (Jeff), really is very good at it. -- Always smile when walking, you never know where there is a camera ;-) Remarkable Coincidences: The Stock Market Crashes of 1929 and 2008 happened on the same date in October. In Oct 1907, a run on the Knickerbocker Trust Company led to the Great Depression. |
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