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#1
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Sum Ting Wong wrote:
On Sat, 27 Dec 2008 21:24:44 GMT, "Dave" wrote: efficiency is only one measure of antenna performance. Exactly. You get it and JS doesn't. S.T.W. Oh, "I get it", you guys just don't get the lack of importance to your point(s!) Correct match to you rig does NOT affect the antennas efficiency, you would still want the most efficient antenna. Antenna length does relate to efficiency, and normally you would erect the longest possible for the freqs, and the efficiency of the antenna is improve, if by nothing else, than capture area ... however, you must balance this against the antenna pattern you wish. The pattern of the antenna, which will be identical in both T/R, is important. Antenna efficiency is important. Match to feedline, and feedline to rig is important. You seem to feel that s/n ratio is something to pursue, I tell you it is not. This is actually handled in the antenna pattern, you do NOT want the antenna to be receptive in the direction(s) of noise sources nor have it prone to static charges and disturbance ... antenna design is what controls this. Your main problem is that you wish to separate all the elements out and be able to deal with each one separately--you can't, every added capacitance adds some measurable amount of inductance, every added inductance adds some measurable amount of capacitance. There is never a case when you wish to decrease antenna efficiency, well, unless you are attempting to construct a dummy load ... If the antenna is "too sensitive" (efficient), crank your rf gain down a bit to the noise floor ... However, if I was supporting a poor antennas' use, or selling a poor antenna, lack of attention to efficiency would be my first "selling point!" Let me repeat, there is NEVER a time a ham or swl'er will want lack of efficiency--they have rf gain controls and other "attenuation boxes" to handle that--you obviously are attempting to confuse antenna efficiency with another aspect of antennas ... indeed, efficiency can be applied to most aspects of an antenna, i.e., "most efficient length", "most efficient match", "most efficient placement", "most efficient design", "most efficient pattern", etc.--and these CAN all vary as to the antennas intended use ... you can never make one change in antenna design which DOES NOT affect all others--i.e., one change makes many ... it is why EZNEC and MMANA-GAL are so desirable to toy with ... load up the software, make one change, watch it affect all others ... well, most of the time. Regards, JS |
#2
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On Sun, 28 Dec 2008 14:43:27 -0800, John Smith
wrote: You seem to feel that s/n ratio is something to pursue, I tell you it is not. You must have been one of the really strong stations I heard during the last ARRL 160m contest that kept calling CQ over and over without being able to hear all the stations that were answering you. It must have been frustrating. 73, S.T.W. |
#3
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Sum Ting Wong wrote:
... You must have been one of the really strong stations I heard during the last ARRL 160m contest that kept calling CQ over and over without being able to hear all the stations that were answering you. It must have been frustrating. 73, S.T.W. Hmmm, from your statements, and text--if adhered to, most-certainly suggests, they must be following your advise, surely! The "alligators", or, i.e., stations which are all mouth and no ears ... However, I am willing to debate, argue, stand-behind, etc., all which I have said ... I actually HAVE built my antennas, and continue to do so .... indeed, my statement is, "Only lamers buy them." Regards, JS |
#4
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John Smith wrote:
... Hmmm, from your statements, and text--if adhered to, most-certainly suggests, they must be following your advise, surely! The "alligators", or, i.e., stations which are all mouth and no ears ... However, I am willing to debate, argue, stand-behind, etc., all which I have said ... I actually HAVE built my antennas, and continue to do so ... indeed, my statement is, "Only lamers buy them." Regards, JS P.S. Just in case you wondered, yes, I did purchase a couple, in the early days ... Regards, JS |
#5
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Sum Ting Wong wrote:
On Sun, 28 Dec 2008 14:43:27 -0800, John Smith wrote: You seem to feel that s/n ratio is something to pursue, I tell you it is not. You must have been one of the really strong stations I heard during the last ARRL 160m contest that kept calling CQ over and over without being able to hear all the stations that were answering you. It must have been frustrating. 73, S.T.W. I have given some thought your statement; I mean, it just strikes me as so bizarre, I ignored it. S/N ratio will NOT improve with an antennas efficiency, indeed, it will increase lineally. The more efficient the antenna (sensitive) the more-efficient it will be at receiving "on frequency noise" from even greater distances. However, a poor antenna may be "efficiently receiving" harmonic related noise which a cheap receiver may have inadequate rejection against ... indeed, there are many "side-scenerios" which are possible. You seem to wish for a very highly efficient/sensitive antenna which will do some sort of noise rejection (or, for some reason, have, in error, given antenna physics this magical/mystical ability(s.)) However, "that/those antenna(s) only exists in science fiction, at least at this date." Surely, you have poor design which is subject to static noise and/or poor antenna pattern which has noise sources within that pattern. And, of course, if one operates an omni antenna, noise is a given, unless you live in a very remote part of the world, or are running a dummy-load as an antenna ... Regards, JS |
#6
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Sum Ting Wong wrote:
On Sun, 28 Dec 2008 14:43:27 -0800, John Smith wrote: You seem to feel that s/n ratio is something to pursue, I tell you it is not. You must have been one of the really strong stations I heard during the last ARRL 160m contest that kept calling CQ over and over without being able to hear all the stations that were answering you. It must have been frustrating. 73, S.T.W. I have given some thought your statement; I mean, it just strikes me as so bizarre, I ignored it. S/N ratio will NOT improve with an antennas efficiency, indeed, it will increase lineally. The more efficient the antenna (sensitive) the more-efficient it will be at receiving "on frequency noise" from even greater distances. However, a poor antenna may be "efficiently receiving" harmonic related noise which a cheap receiver may have inadequate rejection against ... indeed, there are many "side-scenerios" which are possible. You seem to wish for a very highly efficient/sensitive antenna which will do some sort of noise rejection (or, for some reason, have, in error, given antenna physics this magical/mystical ability(s.)) However, "that/those antenna(s) only exists in science fiction, at least at this date." Surely, you have poor design which is subject to static noise and/or poor antenna pattern which has noise sources within that pattern, confused with antenna efficiency. And, of course, if one operates an omni antenna, noise is a given, unless you live in a very remote part of the world, or are running a dummy-load as an antenna ... Regards, JS |
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