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#51
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John Smith wrote:
Dave wrote: ... Not when you're talking about VSWR. Really? First time I have ever heard someone state that! Pray tell, what laws of physics come into play, which disrupts reality, when the antenna is fed from the ether (receiving), rather than developing its' load into the ether? (transmitting) Regards, JS "Pray tell"? Alas and alack. Zounds! Unfortunately, your editing is a bit severe and I have no idea what you're talking about. |
#52
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JB wrote:
... Actually there is no reason TO have a resonant length antenna if you can tune it electrically. After all, you may want to tune around some. I can tell you it is a pain to have to go out and physically make adjustments for any frequency excursion. There are many nonresonant length antennas that outperform the resonant length. The 5/8 wave vertical comes to mind. A long-wire provides a larger capture area. Then there are phased arrays that reinforce. Look up the HAARP project and see how they made a very large array and were able to electrically steer the pattern. Cool! The more you know, the cheaper it gets, and the more you giggle when it works. The only problem is you get hooked and want to do so much more. Well, examine a mechanical tuning fork. They are cut to an exact physical length for resonance, the are very sharp tuning. Now, it would be possible to "lengthen" such a tuning fork with some coil of material, or portion of a turn of material. There is a reason for this; as, although it could be done, it would not be as efficient as one cut to the exact length; plus, you would induce a high probability of increased harmonics as a freq(s) which the fork was not created to induce ... there are exact equivalents in the electrical world of RF ... As you point out, physical length resonance is NOT a requirement ... it is simply "best" ... Regards, JS |
#53
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On Dec 27, 6:14*pm, John Smith wrote:
Dave wrote: ... You are not "pumping" any more "power" into a non-resonant antenna. Unless you are using a tuner you are heating up your finals. First, your use of "resonant" is just plain confusing ... All my multiband antennas, which I have ever use in life, are physically resonate on but one freq (or band.) *On the others, they are only electrically resonate (and, lossy loading components are used to effect this.) A matchbox can always improve the reception on a poorly designed antenna, a mismatched antenna, a non-physically resonate antenna, etc. John Smith, OK then what is a 'matchbox' in : * a poorly designed transmitting antenna, * a mismatched transmitting antenna, * a non-physically resonate transmitting antenna, Consider the 'matchbox' to be one element in the RF Energy Radiating System : Feed-Line + 'matchbox' + Antenna Element i want to know - iane ~ RHF |
#54
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John Smith wrote:
Dave wrote: ... I don't recognize "politician" as being a monolithic culture. There are decent ones and there are many more ****-heads, but that holds true for society in general. I don't believe that. Simply because, in the last 30+ years, I have NEVER seen ANYTHING get any better--or, at least those things which are in the realm of things influenced by politics, legislation produced by politicians, or for that matter, ANYTHING done by politicians! They are there because of their desire for either money, power, or both. They support a shadow government solely for what benefits they, their family and friends get from the individuals in this elite group. Although, the above would be impossible to prove at this date; I believe a through awareness and study of the direction "things" constantly seem to be going in leaves one with no other possible conclusion(s) ... Regards, JS You pretend to be powerless to fight this... |
#55
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Dave wrote:
John Smith wrote: RHF wrote: ... js - but alas i remain a simple shortwave listener who simply enjoys listening to the radio; cause practically speaking; that is what i do - - - respectfully ~ RHF . Quit peeing on my leg ... Brother, I enjoy having a good time, a good drink and the company of a good woman as well as anyone; And, furthermore, I am here because I enjoy a good antenna as well as anyone else. I am here because some know much more than me, can explain it in a manner which I can absorb (Cecil is but one example), and I expect there is much more for us ALL to learn, indeed ... I ain't here to lecture you ... I ain't here to be a ham ... I ain't here to play the game of "one-up-man-ship"; I am here to catch what I missed "the-first-time-around"--end-of-story. But now, a good argument, a good debate, a good "theory-session" ... count me in! Sit back, and pick on the next guy in line ... ;-) Regards, JS A random wire (e.g. inverted L) transmits nicely if you use a tuner at the feed point. A resonate 1/4 wave dipole transmits "nicely" and uses no lossy tuner .... a resonate 1/4 wave vertical monopole, with drooping ground plane, transmits "nicely", requires no lossy tuner, and is damn near a perfect match to 50 ohm coax ... A 1/2 wave version of either of the above produces a superior pattern and can be matched with either a T-match or gamma-match ... indeed, a very minimal counterpoise is all which is necessary--and, if things are "perfect", not even that is needed, or simply a choke on they outside of the coax a ~1/4 wave away from feed point. A 5/8 is non-resonate physical length, and even demonstrates a superior pattern (at least on paper and with antenna prediction software ... ) However, in side-by-side comparisons on 10-6-2m antennas I have built, comparing a 5/8 against the 1/2 (construction methods/materials and matching components identical) ... the actual difference, in the real world, must be less than the width of a meter needle in the readings ... or, put simply, I no longer deal with the extra length required of the 5/8 ... your mileage may vary ... Regards, JS |
#56
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In article ,
Dave wrote: John Smith wrote: Dave wrote: ... Not when you're talking about VSWR. Really? First time I have ever heard someone state that! Pray tell, what laws of physics come into play, which disrupts reality, when the antenna is fed from the ether (receiving), rather than developing its' load into the ether? (transmitting) Regards, JS "Pray tell"? Alas and alack. Zounds! Unfortunately, your editing is a bit severe and I have no idea what you're talking about. He thinks transmitting and receiving antenna engineering is the same thing and reciprocity rules all consideration thereof capture area be damned. That's what happens when you have a pointy head. Go ahead though as he loves to argue about pointless things. -- Telamon Ventura, California |
#57
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In article ,
Dave wrote: John Smith wrote: Dave wrote: ... A random wire (e.g. inverted L) transmits nicely if you use a tuner at the feed point. Nicely is rather a broad term ... And, if I am running 1KW+, or even multi-kilowatts, and the guy on the other end is doing the same--we can communicate "nicely" on very poor antennas ... However, if I am running 5 watts, and the other guy is also, a properly constructed antenna which has been designed around efficiency and most desirable radiation pattern, along with having a correct impedance and is matched EXACTLY to the equipment, and such is done without a lossy "matchbox" or inefficient matching method--these would be of paramount importance. Physics, as much as math, is an EXACT science ... antennas are NOT in realm of "art" (gray areas, open to interpretation, is a matter of personal opinion, etc.), there is but one "best" antenna for any given distance, terrain, pattern, etc. Funny guy that Smith. He has entered the gray area of opinion as to what is best. -- Telamon Ventura, California |
#58
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RHF wrote:
... "N", Don't know too many 'Hams' would would take 50 Feet of common Speaker Wire and tie-a-knot at 30 Feet and then split the two Wires in the remaining 20 Feet and use the thing as a "Stealth" Dipole Antenna with their Transmitter -but- a Shortwave Radio Listener (SWL) can do that and have a very practical SWL Antenna to use with many 'portable' AM&FM Shortwave Radios. 50-Ft. 24-Gauge Clear 2-Conductor Speaker Wire RadioShack Catalog # 278-1301 http://www.radioshack.com/product/in...ductId=2102499 "n" - practically speaking {in practice} there is a difference between between hams and swls ~ RHF . . I have taken ordinary lamp zip cord, split the two leads apart to for a 1/4 wave dipole and fed the end of the remaining length of zip cord with a balun to the rig (some zip cord is ~68-72 ohm balanced line, the mismatch is more than acceptable for field/emergency use.) Never, say never ... some ham will do it! Regards, JS |
#59
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#60
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In article ,
Dave wrote: RHF wrote: Dave, IIRC a good Amateur Radio 1/4 WL Vertical-Up-Leg by 1/4 WL Horizontal-Out-Arm {Inverted "L" Antenna requires very little Tuning and performs very well near and far on the HF Band that it is 'cut' to use on. Using a direct-connect or 1:1 UnUn at the Feed-Point * Half-Wave Inverted "L" Antenna : 1/4 WL + 1/4 WL Where-as the more common Shortwave Listener (SWL) type of {Random Wire} Inverted "L" Antenna is un-equal and usually has a shorter Vertical-Up-Leg and a longer Horizontal-Out-Arm of at least 1V-to-2H and often 1V-to-3H or more. Using a 9:1 Matching Transformer and Ground Rod at the Feed-Point which is at the base of the Vertical-Up-Leg. "Random" implies otherwise. Instead of a 9:1 UnUn, imagine one of these at the feed point: http://www.mfjenterprises.com/Produc...ductid=MFJ-927 I enjoy playing with these kind of things. So I got a license to transmit. Some call that "elitist", I call it self-indulgent. Remote tuners are the right way to do things. Much better than a tuner in the shack. -- Telamon Ventura, California |
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