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#101
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4NEC2?
On 17/10/2018 08:51, Spike wrote:
To bring this back to the issue at hand, I claimed that "I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA" and so far that still stands. With all his blustering and gratuitous personal abuse, Lieberman presents as the Yank version of M3OSN. |
#102
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4NEC2?
Spike wrote:
On 16/10/2018 14:38, Ralph Mowery wrote: In article , lid says... Very interesting, but I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA. You touched on the main vagaries of the system when you said "What I've found is that such side by side comparisons do not account for variations in propagation, path, interference, local noise, time of day, position of the moon, and other factors beyond the operators control". Sometimes it is who is doing the adjusting and not how good the equipment is. That's very true, of course. Some good equipment is in the 'wrong hands'. Almost 40 years ago I started keeping a repeater on the air that was started by someone else. My test equipment at that time was a VTVM, a $ 25 Heathkit signal generator, old Oscilloscope, swr meter, and frequency counter. To tune the receiver my best 'signal generator' was a ham near the edge of the repeater coverage. I would have him just to key down for a minute or two at a time while I adjusted the receiver. Over the years a better receiver and transmitter was installed. Now I have some very good test equipment, but can not say the coverage of the repeater is very much better. What little improvement is made is probably because the radio equipment is better. Thanks! That's just the sort of thing I was on about - in this case you actually used a distant station to help with the set-up, and it worked well. At that time one thing I did not try to adjust or check was the duplexer as I did not think I could with what I had to work with. Many years ago the tuning instructions for duplexers was to tune for maximum signal on the pass and best rejection. As test equipment became better and priced in range, the pass tuning change to using a return loss bridge and SA/TG. This seems to work much better. I found the pass was broad and you could usually give the tuning rod a turn or two without much effect, but he RLB shows up in less than 1/2 of a turn. Does it make a difference ? Probably not in effective coverage (it may extend the range a foot or two,hi), but at least I know it tuned the best it can be with what I have to work with. One thing that does come with better test equipment is knowing that the equipment is tuned so it meets or exceeds the specifications. Before it was just a guess as if the equipment did or did not meet specifications. Quite so. But 'specifications' are often written with other things in mind - compatibility, spurii, stability, etc, and not necessarily anything at all to do with how the distant station receives/perceives one's signal. ISTR it being a licence condition that one checked all the above periodically - more honoured in the breach, perhaps, with commercial kit. -- Roger Hayter |
#103
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4NEC2?
Jeff Liebermann wrote:
On Tue, 16 Oct 2018 07:44:53 +0000, Spike wrote: Very interesting, but I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA. You touched on the main vagaries of the system when you said "What I've found is that such side by side comparisons do not account for variations in propagation, path, interference, local noise, time of day, position of the moon, and other factors beyond the operators control". Perhaps an analogy might be useful. Instead of an HF radio, you're dealing with your automobile. Under normal circumstances, it will get you to work and back fairly efficiently. However, you notice that your gasoline (petrol) mileage is not quite what you might expect. So, you have a choice of mechanics. The first mechanic tunes the engine with a light bulb, divining rod, magic incantations, and offers a rather bizarre description of what work was done on the vehicle. The second mechanic uses proper computerized test equipment to analyze the situation, uses factory parts, and delivers the car with a detailed printout of what was done, what changes were made, what parts were used, and a before-after gas mileage comparison performed on a dynamometer. Now, which mechanic would you prefer? Your car will still go to work and back in some manner. The second mechanic will cost more, because he has to pay for all the expensive equipment and genuine parts. If you're impoverished, obviously the first mechanic will be the only available choice, but assuming you plan to keep the vehicle, one might suspect it is a bad long term solution. From my perspective, both professional and as a ham, I deal in numbers. I can tell by looking at the numbers what is happening and what needs to be done. I have a small collection of aging test equipment to help me generate the numbers. Light bulbs do not generate numbers and are therefore (in my never humble opinion) useless and worthless. However, I will concede that if your intent is "to be able to transmit signals intended to be received by another station", a light bulb is sufficient to determine that your transmitter is spewing RF, spurs, harmonics, and noise into an antenna-like device that is either radiating the RF, absorbing it into heat, or reflecting it back to the transmitter (because the light bulb indicates the same in both directions). Burt won’t appreciate being given an absolute schooling from Jeff here. -- STC / M0TEY / http://twitter.com/ukradioamateur |
#104
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4NEC2?
Gareth's Downstairs Computer
wrote: On 16/10/2018 20:47, Jeff Liebermann wrote: Let me bring it closer to home. You purchased an expensive HF radio with all the bells and whistles. It's out of warranty and you need something fixed. Would you send it to 1) the factory, 2) an authorized repair station, 3) a rebuilder in China, 4) the ham equivalent of the shade tree mechanic, or 5) the teenager next door? If you send to anyone other than yourself then you are not a real radio ham or radio amateur. A CBer, probably. G is for gurgler. -- STC / M0TEY / http://twitter.com/ukradioamateur |
#105
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4NEC2?
On 17/10/2018 10:00, Roger Hayter wrote:
Spike wrote: On 16/10/2018 14:38, Ralph Mowery wrote: In article , lid says... Very interesting, but I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA. You touched on the main vagaries of the system when you said "What I've found is that such side by side comparisons do not account for variations in propagation, path, interference, local noise, time of day, position of the moon, and other factors beyond the operators control". Sometimes it is who is doing the adjusting and not how good the equipment is. That's very true, of course. Some good equipment is in the 'wrong hands'. Almost 40 years ago I started keeping a repeater on the air that was started by someone else. My test equipment at that time was a VTVM, a $ 25 Heathkit signal generator, old Oscilloscope, swr meter, and frequency counter. To tune the receiver my best 'signal generator' was a ham near the edge of the repeater coverage. I would have him just to key down for a minute or two at a time while I adjusted the receiver. Over the years a better receiver and transmitter was installed. Now I have some very good test equipment, but can not say the coverage of the repeater is very much better. What little improvement is made is probably because the radio equipment is better. Thanks! That's just the sort of thing I was on about - in this case you actually used a distant station to help with the set-up, and it worked well. At that time one thing I did not try to adjust or check was the duplexer as I did not think I could with what I had to work with. Many years ago the tuning instructions for duplexers was to tune for maximum signal on the pass and best rejection. As test equipment became better and priced in range, the pass tuning change to using a return loss bridge and SA/TG. This seems to work much better. I found the pass was broad and you could usually give the tuning rod a turn or two without much effect, but he RLB shows up in less than 1/2 of a turn. Does it make a difference ? Probably not in effective coverage (it may extend the range a foot or two,hi), but at least I know it tuned the best it can be with what I have to work with. One thing that does come with better test equipment is knowing that the equipment is tuned so it meets or exceeds the specifications. Before it was just a guess as if the equipment did or did not meet specifications. Quite so. But 'specifications' are often written with other things in mind - compatibility, spurii, stability, etc, and not necessarily anything at all to do with how the distant station receives/perceives one's signal. ISTR it being a licence condition that one checked all the above periodically - more honoured in the breach, perhaps, with commercial kit. That's the sort of road that Liebermann wanted to take the discussion down; an interesting topic but not the issue under discussion. -- Spike "Nearly all men can stand adversity, but if you want to test a man's character, give him an internet group to manage" |
#106
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4NEC2?
Stephen Thomas Cole wrote:
Jeff Liebermann wrote: On Tue, 16 Oct 2018 07:44:53 +0000, Spike wrote: Very interesting, but I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA. You touched on the main vagaries of the system when you said "What I've found is that such side by side comparisons do not account for variations in propagation, path, interference, local noise, time of day, position of the moon, and other factors beyond the operators control". Perhaps an analogy might be useful. Instead of an HF radio, you're dealing with your automobile. Under normal circumstances, it will get you to work and back fairly efficiently. However, you notice that your gasoline (petrol) mileage is not quite what you might expect. So, you have a choice of mechanics. The first mechanic tunes the engine with a light bulb, divining rod, magic incantations, and offers a rather bizarre description of what work was done on the vehicle. The second mechanic uses proper computerized test equipment to analyze the situation, uses factory parts, and delivers the car with a detailed printout of what was done, what changes were made, what parts were used, and a before-after gas mileage comparison performed on a dynamometer. Now, which mechanic would you prefer? Your car will still go to work and back in some manner. The second mechanic will cost more, because he has to pay for all the expensive equipment and genuine parts. If you're impoverished, obviously the first mechanic will be the only available choice, but assuming you plan to keep the vehicle, one might suspect it is a bad long term solution. From my perspective, both professional and as a ham, I deal in numbers. I can tell by looking at the numbers what is happening and what needs to be done. I have a small collection of aging test equipment to help me generate the numbers. Light bulbs do not generate numbers and are therefore (in my never humble opinion) useless and worthless. However, I will concede that if your intent is "to be able to transmit signals intended to be received by another station", a light bulb is sufficient to determine that your transmitter is spewing RF, spurs, harmonics, and noise into an antenna-like device that is either radiating the RF, absorbing it into heat, or reflecting it back to the transmitter (because the light bulb indicates the same in both directions). Burt won't appreciate being given an absolute schooling from Jeff here. I don't appreciate an interesting discussion being interpreted as a schoolyard fight by ignorant troublemakers like you and Gareth. -- Roger Hayter |
#107
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4NEC2?
"Roger Hayter" wrote in message ... Stephen Thomas Cole wrote: Jeff Liebermann wrote: On Tue, 16 Oct 2018 07:44:53 +0000, Spike wrote: Very interesting, but I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA. You touched on the main vagaries of the system when you said "What I've found is that such side by side comparisons do not account for variations in propagation, path, interference, local noise, time of day, position of the moon, and other factors beyond the operators control". Perhaps an analogy might be useful. Instead of an HF radio, you're dealing with your automobile. Under normal circumstances, it will get you to work and back fairly efficiently. However, you notice that your gasoline (petrol) mileage is not quite what you might expect. So, you have a choice of mechanics. The first mechanic tunes the engine with a light bulb, divining rod, magic incantations, and offers a rather bizarre description of what work was done on the vehicle. The second mechanic uses proper computerized test equipment to analyze the situation, uses factory parts, and delivers the car with a detailed printout of what was done, what changes were made, what parts were used, and a before-after gas mileage comparison performed on a dynamometer. Now, which mechanic would you prefer? Your car will still go to work and back in some manner. The second mechanic will cost more, because he has to pay for all the expensive equipment and genuine parts. If you're impoverished, obviously the first mechanic will be the only available choice, but assuming you plan to keep the vehicle, one might suspect it is a bad long term solution. From my perspective, both professional and as a ham, I deal in numbers. I can tell by looking at the numbers what is happening and what needs to be done. I have a small collection of aging test equipment to help me generate the numbers. Light bulbs do not generate numbers and are therefore (in my never humble opinion) useless and worthless. However, I will concede that if your intent is "to be able to transmit signals intended to be received by another station", a light bulb is sufficient to determine that your transmitter is spewing RF, spurs, harmonics, and noise into an antenna-like device that is either radiating the RF, absorbing it into heat, or reflecting it back to the transmitter (because the light bulb indicates the same in both directions). Burt won't appreciate being given an absolute schooling from Jeff here. I don't appreciate an interesting discussion being interpreted as a schoolyard fight by ignorant troublemakers like you and Gareth. what was interesting about it ?..... |
#108
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4NEC2?
On 17/10/2018 14:20, Jim GM4DHJ ... wrote:
"Roger Hayter" wrote in message Stephen Thomas Cole wrote: Jeff Liebermann wrote: On Tue, 16 Oct 2018 07:44:53 +0000, Spike wrote: Very interesting, but I'd have to say that none of what you say refutes my original contention that the distant station, which after all is the one we are trying to communicate with, will notice any difference to the received signal whether the sending station's antenna was tuned with a 20c torch bulb or a $300 VNA. You touched on the main vagaries of the system when you said "What I've found is that such side by side comparisons do not account for variations in propagation, path, interference, local noise, time of day, position of the moon, and other factors beyond the operators control". Perhaps an analogy might be useful. Instead of an HF radio, you're dealing with your automobile. Under normal circumstances, it will get you to work and back fairly efficiently. However, you notice that your gasoline (petrol) mileage is not quite what you might expect. So, you have a choice of mechanics. The first mechanic tunes the engine with a light bulb, divining rod, magic incantations, and offers a rather bizarre description of what work was done on the vehicle. The second mechanic uses proper computerized test equipment to analyze the situation, uses factory parts, and delivers the car with a detailed printout of what was done, what changes were made, what parts were used, and a before-after gas mileage comparison performed on a dynamometer. Now, which mechanic would you prefer? Your car will still go to work and back in some manner. The second mechanic will cost more, because he has to pay for all the expensive equipment and genuine parts. If you're impoverished, obviously the first mechanic will be the only available choice, but assuming you plan to keep the vehicle, one might suspect it is a bad long term solution. From my perspective, both professional and as a ham, I deal in numbers. I can tell by looking at the numbers what is happening and what needs to be done. I have a small collection of aging test equipment to help me generate the numbers. Light bulbs do not generate numbers and are therefore (in my never humble opinion) useless and worthless. However, I will concede that if your intent is "to be able to transmit signals intended to be received by another station", a light bulb is sufficient to determine that your transmitter is spewing RF, spurs, harmonics, and noise into an antenna-like device that is either radiating the RF, absorbing it into heat, or reflecting it back to the transmitter (because the light bulb indicates the same in both directions). Burt won't appreciate being given an absolute schooling from Jeff here. I don't appreciate an interesting discussion being interpreted as a schoolyard fight by ignorant troublemakers like you and Gareth. what was interesting about it ?..... The clash of cultures between the open-minded out-of-the-box thinker, and a rules-and-regulations-trump-everything engineer. We have the latter type on UKRA too, more's the pity. Then there's those that don't know a sideband from a sideburn, waving their 'Vouvray for our side' banners. In all senses of the word. -- Spike "Nearly all men can stand adversity, but if you want to test a man's character, give him an internet group to manage" |
#109
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4NEC2?
On Wed, 17 Oct 2018 08:48:04 +0100, Gareth's Downstairs Computer
wrote: On 16/10/2018 20:47, Jeff Liebermann wrote: Let me bring it closer to home. You purchased an expensive HF radio with all the bells and whistles. It's out of warranty and you need something fixed. Would you send it to 1) the factory, 2) an authorized repair station, 3) a rebuilder in China, 4) the ham equivalent of the shade tree mechanic, or 5) the teenager next door? If you send to anyone other than yourself then you are not a real radio ham or radio amateur. Are you suggesting that you have the ability to repair a modern HF radio? Do you have the equipment? Do you have the knowledge? I have both and believe me, it's often very difficult. Today's electronics is not made to be easily repaired. 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, and unfortunately, my IFR-1500 service monitor. All of them are the results of botched repairs. Can you do better? After you fail, which of the above 5 choices would be your next step? Or would you just sell the radio and pretend there was nothing wrong? A CBer, probably. It's interesting that all of your brilliant pontifications include a derogatory comment about CB'ers. That's odd because I've always assumed that you are a CB'er or at least own and use a CB radio. Is that true? Is it possible for you to write something without mentioning CB or insulting the reader in some manner? Judging by your past history, I doubt it. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#110
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4NEC2?
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. Anyway, I would rant some more, but I'm late for an exercise trudge in the local state park followed by a lunch meeting with the local hams. More rants later, if I survive. -- 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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