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#11
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"Cecil Moore" wrote in message ... Jimmy wrote: Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna if it is physically only 4ft long or would this be an 1/8 wavelength antenna(more or less).I am saying this should be called an 1/8 wl antenna though I am arguing with those who generally know more more about this than I. Not all the old timers disagree with me, so I am betting this is a pretty common problem when discussing antennas. What you have is a *physically* short antenna that is *electrically* Does this mean that I can call a 5/8 antenna a 3/4? I would think it should be one way or the other. I was really hoping for a more definative answer than I have gotten here so far as there is a signiificant quantity of beer at stake. I know what I have I just want someone to settle the argument on what it should be called. In other words, should we use physical length or electrical length to describe an antenna. It is my opinion that antennas should be referenced by there physical length otherwise we will be giving creedance to those who are trying to sell 5/8wl antennas that are physically only an 1/8wl long. 1/4WL long. This usually involves a loading coil. Also, the electrical length of a piece of coax is longer than it's physical length because of the velocity factor less than 1.0. -- 73, Cecil http://www.qsl.net/w5dxp -----= 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! =----- |
#12
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"Arrow146" wrote in message ... If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even if it is physically shortened by use of coils. Alex / AB2RC If that is true, then there is no such thing as a 5/8 wave antenna. They would be 3/4 wave antennas. Don't think so. 73 Al Lowe N0IMW Al, This was the basis of my thoughts on the subject too, Im the OP. Im of the opinion an antenna shorter than 1/4 wll should either be identified by its fractional wl dimension or as a loaded x freq antenna y units long. Otherwise those who advertise 5/8 antennas that are physically 1/8wl long have every right to do so. |
#13
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To avoid misunderstandings, which often end up in vicious arguments, there
is no alternative but to think about it and say exactly what you mean. Then read what you have written and think AGAIN. Avoid old-wives' jargon. Have a free program. ---- .................................................. .......... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp .................................................. .......... |
#14
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The radiation patterns for a 1/4 and a loaded 1/8 wave should be
slightly different. If so, ERGO! Two different antennas. Boy, this stuff is tough! :-) Jimmy wrote: Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna if it is physically only 4ft long or would this be an 1/8 wavelength antenna(more or less).I am saying this should be called an 1/8 wl antenna though I am arguing with those who generally know more more about this than I. Not all the old timers disagree with me, so I am betting this is a pretty common problem when discussing antennas. |
#15
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Alex Flinsch wrote in message ...
In article , Arrow146 wrote: If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even if it is physically shortened by use of coils. Alex / AB2RC If that is true, then there is no such thing as a 5/8 wave antenna. They would be 3/4 wave antennas. since when does 5/8 = 3/4 ? last time I checked, 3/4 = 6/8 A 5/8 ground plane is tuned to a 3/4 wave resonance. Myself, I think they should be described as their actual physical length. That gives you a better idea of their true performance. If you called a 5/8 antenna , a 3/4 wave, in my mind, the gain on the horizon drops and higher angle lobes start to appear...Then you have the cases of the "short" 1/2 waves...The shorty versions will never have the gain that a true full size half wave will. Calling them 1/2 waves is misleading. When I talk about my 10 ft tall mobile antenna, it's a 1/4 wave resonance anywhere I tune the antenna. But I don't go around calling it a 1/4 wave...I call it a 10 ft center loaded vertical. In my book, to be called a 1/4 wave, it needs to actually be a 1/4 wave in physical length. I'd call his antenna, a 1/8 wave tall loaded vertical. MK |
#16
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If that is true, then there is no such thing as a 5/8 wave antenna. They
would be 3/4 wave antennas. since when does 5/8 = 3/4 ? last time I checked, 3/4 = 6/8 Sense always. A two meter 5/8 wave length (48") whip does not work very well. A 3/4 wave length whip will tune up fine (low SWR) but has a very high angle of radiation, still does not work well. Take 1/8 wave (about 9 1/2 inches) of the 3/4 wave and turn it into a coil. And you end up with an antenna about 48" tall that works real well. (5/8 wave = 48") I guess if you want to follow the CB Hipe about antennas, it's up to you. You think a 3 ft. 11 meter antenna that claims to be of 5/8 wave antenna, works like a true 5/8 wave length Antenna - - I think I will stop here. I have a lot more important things I should be doing. Arrow Antenna lost its lease on our building, wo we had to move. I have a lot of equipment to get hooked up again so we can get back into the production of real antennas. 73 Al Lowe N0IMW ArrowAntenna.com 911 East Fox Farm Road. #2 Cheyenne, WY 82007 307-638-2369 Fax 307-638-3521 |
#17
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Thanks Bill. I was worried more about the (hopefully mild) attacks on the
propensity to nit pick on words or (what almost seems like intentional) mis understanding due to the way terminology is used. I haven't read all the other posts yet, but I made the decision to ignore this detail (loaded ant feed Z) since it didn't help the naming problem. I really try to address the OP's question without clouding it with other probably true, but very possibly confusing details. Of course, there is no guarantee that the loading coil actually does get you to a zero reactance, thought we like to think we can do that -- and that was my assumption. I think I said, or at least wanted to imply that we try to get back to a zero reactance (a.k.a. resonance) and _that_ is "just like" the "real" 1/4 wave....and therefore, perhaps, that is why some may want to call it a 1/4 wave, but I am guessing what others think. I don't know who wanted to call it a 1/4 wave in the previous posts. -- Steve N, K,9;d, c. i My email has no u's. "Bill Turner" wrote in message ... On Tue, 20 Jan 2004 17:48:28 -0600, "Steve Nosko" wrote: ...[ gobs'n gobs snipped] __________________________________________________ _______ An excellent explanation, Steve, but needing one correction. When adding a loading coil as above, the feed point resistance drops significantly, so it no longer appears to be "just like a 1/4 wave antenna". Otherwise, great post. For the benefit of the original poster, the word is "semantics". -- 73, Bill W6WRT |
#18
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Mikey,
You'll have to read more of the other posts. I particularly recommend mine. "Steve Nosko" wrote in message ... If it is gone, I can re-post -- Steve N, K,9;d, c. i My email has no u's. "Mikey" wrote in message ... Jimmy, I don't see the connection between "resonant" and "1/4-wavelength", at least from what you posted. And, in this universe, 4 ft. is NOT 1/4 on 10 meters... - KI6PR El Rancho R.F., CA "Jimmy" wrote Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna if it is physically only 4ft long or would this be an 1/8 wavelength antenna(more or less).I am saying this should be called an 1/8 wl antenna though I am arguing with those who generally know more more about this than I. Not all the old timers disagree with me, so I am betting this is a pretty common problem when discussing antennas. |
#19
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WHOA!! Now, you didn't mention the beer before. Let me know if my
explanation helped...and what my cut of the beer is. I pasted the message ID if it is gone, or I can re-post. -- Steve N, K,9;d, c. i My email has no u's. "Steve Nosko" wrote in message ... "Jimmy" wrote in message . com... "Cecil Moore" wrote in message ... Jimmy wrote: Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna if it is physically only 4ft long or would this be an 1/8 wavelength antenna(more or less).I am saying this should be called an 1/8 wl antenna though I am arguing with those who generally know more more about this than I. Not all the old timers disagree with me, so I am betting this is a pretty common problem when discussing antennas. What you have is a *physically* short antenna that is *electrically* Does this mean that I can call a 5/8 antenna a 3/4? I would think it should be one way or the other. I was really hoping for a more definative answer than I have gotten here so far as there is a signiificant quantity of beer at stake. I know what I have I just want someone to settle the argument on what it should be called. In other words, should we use physical length or electrical length to describe an antenna. It is my opinion that antennas should be referenced by there physical length otherwise we will be giving creedance to those who are trying to sell 5/8wl antennas that are physically only an 1/8wl long. 1/4WL long. This usually involves a loading coil. Also, the electrical length of a piece of coax is longer than it's physical length because of the velocity factor less than 1.0. -- 73, Cecil http://www.qsl.net/w5dxp -----= 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! =----- |
#20
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Arrow, One of those important things might be to explain to me how 9 1/2" is a 1/8 wave at what frequency? I thought we were talking 10 meters... 'Doc |
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