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#22
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In , sideband
wrote: Seems to me old Frankie has a bit to learn about how balanced antennas work. Oboy, here we go again.... are you about to say something really stupid, like balanced antennas receive the same regardless of how well they transmit? Or that a non-resonant dipole will receive just as well as a resonant dipole? Or that balanced antennas are -not- reciprocal (which would conflict with everything that has been learned in the field of radio for over a century)? Go right ahead, Sideband -- educate me as to how balanced antennas work! -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#23
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Oh, goodie.. time to clean up the trash.
Frank Gilliland wrote: In , sideband wrote: Seems to me old Frankie has a bit to learn about how balanced antennas work. Oboy, here we go again.... are you about to say something really stupid, like balanced antennas receive the same regardless of how well they transmit? No, you said that. I didn't have to. However, a non resonant antenna showing a high SWR and a high RADIATION resistance will receive better than it transmits, regardless of what phunkiephysics you're trying to apply. Or that a non-resonant dipole will receive just as well as a resonant dipole? Nope.. again.. you said that.. However, you should know that the difference between an antenna receiving in resonance and one receiving out of resonance (depending on how far out of resonance) is in the nanovolt to miccrovolt range... so you might lose an s-unit or two on receive. However a dipole showing a 2:1 SWR, as the op has presented, isn't going to make that much of a difference in either transmit or receive. Read some ARRL books, Frankie. Or that balanced antennas are -not- reciprocal (which would conflict with everything that has been learned in the field of radio for over a century)? No antenna is 1:1 "reciprocal" (as you call it).. The ability of the antenna to radiate RF is not proportional to its ability to receive. The sooner you get THAT out of YOUR head, you might actually stop spreading bull**** false information. Go right ahead, Sideband -- educate me as to how balanced antennas work! Again, go read a book, if you can get past your preconceived notions that you know it all, you might actually learn something -----= Posted via Newsfags.Com, Uncensored Usenet Homosexuality =----- http://www.newsfags.com - The #1 Newfag Service in the World! -----== Over 100,000 Newsfags - 19 Different Servers! =----- -SSB P.S. My spellchecker keeps wanting to replace "Frankie" with "France"... Go figure. |
#24
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Speaking of wire dipoles..........
Have a look at this one. It's a distributed capacity coaxial wire dipole antenna. There are no formulas, but it looks interesting. Should start another interesting thread.......... http://www.k9gd.com/DCCDA.html |
#25
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![]() CP, It's actually called a 'Double Bazooka' antenna and has been around for ever. While it appears to be broaderbanded than a 1/2 wave dipole, the problem is that the radiation efficiency tapers off as you get to the extremes of the frequency coverage. It will still show a low SWR, but because of several things (reactances mostly), the radiation level decreases so that you actually aren't radiating any more than if you were using a 1/2 wave dipole with a high SWR. The net gain over a common 1/2 wave dipole is zero. It is a fairly 'quiet' antenna, not quite as much noise as the common dipole. At HF the diameter of the conductors make no difference in the antenna's being broadbanded. The diameter has to be increased to a sizable percentage of a wave length before it really makes any appreciable difference. Something like 6 feet diameter at 80 meters, and around 2 feet at 10/11 meters. There is a formula for this type of antenna. You need to know the velocity factor for the kind of coax you use. Cut the total length of the dipole for (468/f{in Mhz}) = L1. Find the electrical 1/2 wave length by multiplying this L1 by the coax's velocity factor = L2. Subtract L2 from L1, divide it by two, and that's how far from each end to short the inner conductor and braid. The rest of the antenna is done as in the example. There's a pretty good examination of coaxial dipoles in one of the ARRL's Antenna Compendium books. 'Doc PS - The 'CCD' or Controled Capacitance Distribution antenna is a whole 'nuther animal. |
#26
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In , sideband
wrote: Oh, goodie.. time to clean up the trash. Frank Gilliland wrote: In , sideband wrote: Seems to me old Frankie has a bit to learn about how balanced antennas work. Oboy, here we go again.... are you about to say something really stupid, like balanced antennas receive the same regardless of how well they transmit? No, you said that. I didn't have to. However, a non resonant antenna showing a high SWR and a high RADIATION resistance will receive better than it transmits, regardless of what phunkiephysics you're trying to apply. Wrong. You should know already that any antenna with a high radiation resistance is an efficient radiator. And it just so happens that a dipole has it's highest radiation resistance when it is resonant. SWR is not even a factor in this topic. Or that a non-resonant dipole will receive just as well as a resonant dipole? Nope.. again.. you said that.. However, you should know that the difference between an antenna receiving in resonance and one receiving out of resonance (depending on how far out of resonance) is in the nanovolt to miccrovolt range... so you might lose an s-unit or two on receive. I agree to a point. Care to quantify that statement? However a dipole showing a 2:1 SWR, as the op has presented, isn't going to make that much of a difference in either transmit or receive. Read some ARRL books, Frankie. I agree. What's your point? Or that balanced antennas are -not- reciprocal (which would conflict with everything that has been learned in the field of radio for over a century)? No antenna is 1:1 "reciprocal" (as you call it).. The ability of the antenna to radiate RF is not proportional to its ability to receive. Wrong again. It is DIRECTLY proportional, all other factors being equal (IOW, you aren't heating the wires with zillions of watts). The sooner you get THAT out of YOUR head, you might actually stop spreading bull**** false information. You need to spend a little time at the library. Find a nice book on electromagnetics, then search through the index for the terms 'radiation intensity' and 'effective aperature'. I think you will find them on pages very close to each other, if not on the same page. And you will notice that the mathematical definitions of both terms are almost identical -- in fact, I have one book that provides a formula to convert between the two. Why? Because they are DIRECTLY RELATED, and that's why antennas are RECIPROCAL. Or maybe you think that someone came up with the concept out of thin air.... Go right ahead, Sideband -- educate me as to how balanced antennas work! Again, go read a book, if you can get past your preconceived notions that you know it all, you might actually learn something My "preconcieved notions" come from the books you want me to read. Read them yourself. -----= Posted via Newsfags.Com, Uncensored Usenet Homosexuality =----- http://www.newsfags.com - The #1 Newfag Service in the World! -----== Over 100,000 Newsfags - 19 Different Servers! =----- -SSB P.S. My spellchecker keeps wanting to replace "Frankie" with "France"... Go figure. Read the directions. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#27
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killdagger wrote...
Greetings, I've got me an RCA CB Co pilot 14T303 with a workman BS-1 dipole antenna pinnes up in an inverted v outside my window. I recieve just fine, but my transmit is horrible. Some people seem to believe that some antennas work best for receive and others for transmit... but it is wrong. An antenna will work just as well for both, either it is good or it is not. One issue could be that some people may have their squelch set higher, or they may not be listening for the weak signals. Another issue is that a receiver being swamped with many fairly strong signals will have the gain drop, so a poor antenna will give the radio weaker signals and the RX gain may go back up. A few years back, most of the UK TV stations shut down at night. When this happened, my TV RX gain would go back up and I could pick up remaining transmitters from 100s of miles away - on a small indoor antenna. If, on a good antenna, your TX seems to be much worse than your RX, then have the radio checked. Well, I checked the SWR. 1.5 @ ch.1 and a hair below 2 on 40. The readings suggest that the antenna is slightly long, but not enough to worry about too much. Other nearby objects will affect the SWR. SWR is not critical, a vertical dipole will normally be about 75 Ohms - giving a 1.5:1 SWR reading at best. As for the inverted dipole, do you reccommend i mount it as an 'L'? Vertical would be best but, if space is limited, you may need to settle for something more compact. Regards, Peter. |
#28
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![]() Lance Adair KK4TI wrote: "Richard Cranium" wrote in message om... Frank Gilliland wrote in message . .. In , sideband wrote: Hrm.. Wonder where Frankie's intelligent reply is... Oh, wait, I guess this is it, as this is the best he can manage. -SSB You need to see someone about your communication deficit, because I answered the OP's question in another post. Now **** off. Shame on you, Frankie-fag; you've been hanging around with the perverts (Doggie and Georgie-girl) so long you're starting to post like them. well look at dickie cranium your starting to post like dougie too assclown, nothing but fag this and gay that in your post dickie boy cranium... Potty mouth Lance Adair strikes again. |
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