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#1
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Robert Morein wrote:
Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... |
#2
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![]() "ric" wrote in message ... Robert Morein wrote: Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. |
#3
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![]() "Robert Morein" wrote in message ... "ric" wrote in message ... Robert Morein wrote: Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. I do. It worked in his location. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. There's more to antennas than theory, especially these "little ones". As I stated before, I don't have any experience of this particular antenna but I have plenty of experience of seemingly similar design, The Magnum Dynalab ST-2. http://www.magnumdynalab.com/x_st2.htm It has worked admirably well over the years in many urban locations except one. NYC RF hell rendered it pretty much useless. However, at the time I did not have the Signal Sleuth that greatly complements the whip albeit at a considerable cost. http://www.magnumdynalab.com/x_sleuth.htm Based on my "nontechnical" opinion I can say that the whip alone generally outperforms the "grocerybagful" of dipoles I've accumulated over the years by a comfortable margin. With the Sleuth, it is the ultimate quick and small FM antenna solution. One of my favorite tuners has a scope that allows the monitoring of multipath signals and contrary to what one might think, the ST-2 is not all that easily bothered by it. That said, there are locations, such as NYC, where the cheap but nearly unobtainable Dennesen dual whip cannot be beat. I suspect that the Dennesen would be an easy DIY project for those so inclined. But no one should fool themselves into thinking that any of these products will succesfully compete with a competent outdoor antenna such as those made by APS. Cheers, Margaret |
#4
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![]() "Margaret von B." wrote in message ... "Robert Morein" wrote in message ... "ric" wrote in message ... Robert Morein wrote: Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. I do. It worked in his location. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. There's more to antennas than theory, especially these "little ones". As I stated before, I don't have any experience of this particular antenna but I have plenty of experience of seemingly similar design, The Magnum Dynalab ST-2. http://www.magnumdynalab.com/x_st2.htm It has worked admirably well over the years in many urban locations except one. NYC RF hell rendered it pretty much useless. However, at the time I did not have the Signal Sleuth that greatly complements the whip albeit at a considerable cost. http://www.magnumdynalab.com/x_sleuth.htm Based on my "nontechnical" opinion I can say that the whip alone generally outperforms the "grocerybagful" of dipoles I've accumulated over the years by a comfortable margin. With the Sleuth, it is the ultimate quick and small FM antenna solution. One of my favorite tuners has a scope that allows the monitoring of multipath signals and contrary to what one might think, the ST-2 is not all that easily bothered by it. That said, there are locations, such as NYC, where the cheap but nearly unobtainable Dennesen dual whip cannot be beat. I suspect that the Dennesen would be an easy DIY project for those so inclined. But no one should fool themselves into thinking that any of these products will succesfully compete with a competent outdoor antenna such as those made by APS. Cheers, Margaret Margaret, without contradicting your experience, I think that the difference in sound has to do with the placement of the antenna. Perhaps the freestanding whip was placeable in a way that the dipole was not. The real solution comes from an antenna arrangement with some directionality. If the multipath signal(s) can be reduced below one particular strongest signal, then phase cancellation cannot occur. Two whips separated by 1/2 wavelength can be directionally oriented by a combining phase shift network, which is probably why your Dennesen worked so well. A single vertical whip receives equally well from all directions. This means that reduction in multipath can be accomplished only by moving the antenna about the room. By contrast, a dipole can be rotated through 180 vertically, and 180 degrees horizontally, while in the same location, provided one can find a way to support the floppy wires. Taping it to a dowell stick would work. |
#5
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![]() "Robert Morein" wrote in message ... "Margaret von B." wrote in message ... "Robert Morein" wrote in message ... "ric" wrote in message ... Robert Morein wrote: Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. I do. It worked in his location. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. There's more to antennas than theory, especially these "little ones". As I stated before, I don't have any experience of this particular antenna but I have plenty of experience of seemingly similar design, The Magnum Dynalab ST-2. http://www.magnumdynalab.com/x_st2.htm It has worked admirably well over the years in many urban locations except one. NYC RF hell rendered it pretty much useless. However, at the time I did not have the Signal Sleuth that greatly complements the whip albeit at a considerable cost. http://www.magnumdynalab.com/x_sleuth.htm Based on my "nontechnical" opinion I can say that the whip alone generally outperforms the "grocerybagful" of dipoles I've accumulated over the years by a comfortable margin. With the Sleuth, it is the ultimate quick and small FM antenna solution. One of my favorite tuners has a scope that allows the monitoring of multipath signals and contrary to what one might think, the ST-2 is not all that easily bothered by it. That said, there are locations, such as NYC, where the cheap but nearly unobtainable Dennesen dual whip cannot be beat. I suspect that the Dennesen would be an easy DIY project for those so inclined. But no one should fool themselves into thinking that any of these products will succesfully compete with a competent outdoor antenna such as those made by APS. Cheers, Margaret Margaret, without contradicting your experience, I think that the difference in sound has to do with the placement of the antenna. That's probably most of it. As I said, "there's more than theory"... Perhaps the freestanding whip was placeable in a way that the dipole was not. The real solution comes from an antenna arrangement with some directionality. If the multipath signal(s) can be reduced below one particular strongest signal, then phase cancellation cannot occur. Two whips separated by 1/2 wavelength can be directionally oriented by a combining phase shift network, which is probably why your Dennesen worked so well. It still works, if I can stand to look at it. :-) However, my primary residence sports a Sniper these days with Yaesu rotor. A single vertical whip receives equally well from all directions. This means that reduction in multipath can be accomplished only by moving the antenna about the room. By contrast, a dipole can be rotated through 180 vertically, and 180 degrees horizontally, while in the same location, provided one can find a way to support the floppy wires. Taping it to a dowell stick would work. I hear you, but when using an A/B switch and watching the trace as you switch antennas, any changes in multipath reception are easily detected. Using such setup, I can only conclude that the ST-2, generally speaking, is not impeded by multipath reception and will deliver a stronger, cleaner signal to a tuner than a R/S dipole and its cousins. Cheers, Margaret |
#6
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![]() "Margaret von B." wrote in message news ![]() "Robert Morein" wrote in message ... "Margaret von B." wrote in message ... "Robert Morein" wrote in message ... "ric" wrote in message ... Robert Morein wrote: Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. I do. It worked in his location. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. There's more to antennas than theory, especially these "little ones". As I stated before, I don't have any experience of this particular antenna but I have plenty of experience of seemingly similar design, The Magnum Dynalab ST-2. http://www.magnumdynalab.com/x_st2.htm It has worked admirably well over the years in many urban locations except one. NYC RF hell rendered it pretty much useless. However, at the time I did not have the Signal Sleuth that greatly complements the whip albeit at a considerable cost. http://www.magnumdynalab.com/x_sleuth.htm Based on my "nontechnical" opinion I can say that the whip alone generally outperforms the "grocerybagful" of dipoles I've accumulated over the years by a comfortable margin. With the Sleuth, it is the ultimate quick and small FM antenna solution. One of my favorite tuners has a scope that allows the monitoring of multipath signals and contrary to what one might think, the ST-2 is not all that easily bothered by it. That said, there are locations, such as NYC, where the cheap but nearly unobtainable Dennesen dual whip cannot be beat. I suspect that the Dennesen would be an easy DIY project for those so inclined. But no one should fool themselves into thinking that any of these products will succesfully compete with a competent outdoor antenna such as those made by APS. Cheers, Margaret Margaret, without contradicting your experience, I think that the difference in sound has to do with the placement of the antenna. That's probably most of it. As I said, "there's more than theory"... Perhaps the freestanding whip was placeable in a way that the dipole was not. The real solution comes from an antenna arrangement with some directionality. If the multipath signal(s) can be reduced below one particular strongest signal, then phase cancellation cannot occur. Two whips separated by 1/2 wavelength can be directionally oriented by a combining phase shift network, which is probably why your Dennesen worked so well. It still works, if I can stand to look at it. :-) However, my primary residence sports a Sniper these days with Yaesu rotor. A single vertical whip receives equally well from all directions. This means that reduction in multipath can be accomplished only by moving the antenna about the room. By contrast, a dipole can be rotated through 180 vertically, and 180 degrees horizontally, while in the same location, provided one can find a way to support the floppy wires. Taping it to a dowell stick would work. I hear you, but when using an A/B switch and watching the trace as you switch antennas, any changes in multipath reception are easily detected. Using such setup, I can only conclude that the ST-2, generally speaking, is not impeded by multipath reception and will deliver a stronger, cleaner signal to a tuner than a R/S dipole and its cousins. Cheers, Margaret I don't doubt the result. Your reply has forced me to additional thought: 1.Mere inches are significant to multipath. 2. The other thing which is signficant is this: the ST-2 connects to the receiver by coax, which picks up negligible signal by itself. The twinlead from a folded dipole is part of the antenna system itself. Therefore, it picks up more signal, which can cancel with that received by the nominal antenna. Back in the 60's, people would prewire their houses with twinlead for a rooftop TV antenna, and the ghosting (visual multipath) was vicious. Replacing it with coax eliminated the distribution system as a secondary antenna. I should append the following note to my original advice to "ric". After constructing his custom 33.5" folded dipole, he should purchase a balun transformer from Radio Shack or any other source. He should connect the pigtails on the balun to the feed of the dipole, and he should run coaxial cable to his receiver. |
#7
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![]() "Robert Morein" wrote in message ... "Margaret von B." wrote in message news ![]() "Robert Morein" wrote in message ... "Margaret von B." wrote in message ... "Robert Morein" wrote in message ... "ric" wrote in message ... Robert Morein wrote: Are you familiar with the FM2G-C? It is being strongly considered. http://www.fanfare.com/fm-2g-c.html This is an omnidirectional antenna, which means it will be very susceptible to multipath. The fact that it is cut for the educational band gives it a little more gain, but, as I said, gain is seldom the problem. The problem is phase cancellation caused by reception of a signal that is reflected by two or more different paths. This causes the signal to actually cancel 100% at certain frequencies. More gain on nothing does not result in something. The solution is a directional antenna, which attenuates all but one of the reception paths, eliminating the phase cancellation. Hmmm...I'm getting a slew of opinions on this, and few of them reach the same conclusion. Such as: http://www.hawaiipublicradio.org/recep.htm I've tried various dipole antennas, all with similar results. Best results so far was an RCA powered indoor TV "rabbit ear" type antenna. I'm tempted to have an antenna cut specifically for 88.3 MHz, as that is the only FM I listen to. Oh well... You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. I do. It worked in his location. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. There's more to antennas than theory, especially these "little ones". As I stated before, I don't have any experience of this particular antenna but I have plenty of experience of seemingly similar design, The Magnum Dynalab ST-2. http://www.magnumdynalab.com/x_st2.htm It has worked admirably well over the years in many urban locations except one. NYC RF hell rendered it pretty much useless. However, at the time I did not have the Signal Sleuth that greatly complements the whip albeit at a considerable cost. http://www.magnumdynalab.com/x_sleuth.htm Based on my "nontechnical" opinion I can say that the whip alone generally outperforms the "grocerybagful" of dipoles I've accumulated over the years by a comfortable margin. With the Sleuth, it is the ultimate quick and small FM antenna solution. One of my favorite tuners has a scope that allows the monitoring of multipath signals and contrary to what one might think, the ST-2 is not all that easily bothered by it. That said, there are locations, such as NYC, where the cheap but nearly unobtainable Dennesen dual whip cannot be beat. I suspect that the Dennesen would be an easy DIY project for those so inclined. But no one should fool themselves into thinking that any of these products will succesfully compete with a competent outdoor antenna such as those made by APS. Cheers, Margaret Margaret, without contradicting your experience, I think that the difference in sound has to do with the placement of the antenna. That's probably most of it. As I said, "there's more than theory"... Perhaps the freestanding whip was placeable in a way that the dipole was not. The real solution comes from an antenna arrangement with some directionality. If the multipath signal(s) can be reduced below one particular strongest signal, then phase cancellation cannot occur. Two whips separated by 1/2 wavelength can be directionally oriented by a combining phase shift network, which is probably why your Dennesen worked so well. It still works, if I can stand to look at it. :-) However, my primary residence sports a Sniper these days with Yaesu rotor. A single vertical whip receives equally well from all directions. This means that reduction in multipath can be accomplished only by moving the antenna about the room. By contrast, a dipole can be rotated through 180 vertically, and 180 degrees horizontally, while in the same location, provided one can find a way to support the floppy wires. Taping it to a dowell stick would work. I hear you, but when using an A/B switch and watching the trace as you switch antennas, any changes in multipath reception are easily detected. Using such setup, I can only conclude that the ST-2, generally speaking, is not impeded by multipath reception and will deliver a stronger, cleaner signal to a tuner than a R/S dipole and its cousins. Cheers, Margaret I don't doubt the result. Your reply has forced me to additional thought: 1.Mere inches are significant to multipath. 2. The other thing which is signficant is this: the ST-2 connects to the receiver by coax, which picks up negligible signal by itself. The twinlead from a folded dipole is part of the antenna system itself. Therefore, it picks up more signal, which can cancel with that received by the nominal antenna. Back in the 60's, people would prewire their houses with twinlead for a rooftop TV antenna, and the ghosting (visual multipath) was vicious. Replacing it with coax eliminated the distribution system as a secondary antenna. I should append the following note to my original advice to "ric". After constructing his custom 33.5" folded dipole, he should purchase a balun transformer from Radio Shack or any other source. He should connect the pigtails on the balun to the feed of the dipole, and he should run coaxial cable to his receiver. That should do it. OTOH, the person who bought my old "nightmare reception" loft in NYC simply ended up buying a Blaupunkt car stereo with a diversity tuner and got better results than with any home units at a fraction of the cost. Of course one still needs to optimize antenna location, but it is pretty much set and forget. I was stunned how well it worked. In fact, I should buy one of those Blaupunkts and compare it to my existind tuners for the fun of it. I believe even the Audio Critic did an article on the Blaupunkt tuners after they got a whiff of it... Cheers, Margaret |
#8
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On Wed, 22 Jun 2005 20:56:44 -0400, "Robert Morein"
wrote: The twinlead from a folded dipole is part of the antenna system itself. Therefore, it picks up more signal, which can cancel with that received by the nominal antenna. ********! (7) It is a balanced transmission line which is matched to the balanced 300ohm folded dipole. The fields associated with the twin conductors of the feeder cancel in the far field. It cannot radiate/recieve itself if it is properly balanced. Back in the 60's, people would prewire their houses with twinlead for a rooftop TV antenna, and the ghosting (visual multipath) was vicious. Replacing it with coax eliminated the distribution system as a secondary antenna. "twinlead" has lower losses than coax, (for similar size/cost) however the disadvantage is that the fields extend outside the bounds of the cable, whereas with coax it is within. To get the best out of balanced feed it should be spaced away from other materials. Coax can be attached to walls, taped to metal poles, etc. It also needs a decent balun to connect to a dipole. |
#9
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On Wed, 22 Jun 2005 08:56:42 -0400, "Robert Morein"
wrote: One is disappointed in f'ing wannabee Usenet scientists. . . The wavelength of 88.3 mHz milli Hertz? is 66.88 inches. ********! Try twice that. (300e6 /88.3e6 x100/2.54) inches. Your dipole should be 1/2 that length: 33.5. All you need is a piece of twinlead, which is just junky antenna lead-in wire. Cut it to 33.5 inches. At each end, twist the conductors together. At the center, break one conductor. Connect the loose ends to your feed wire. It is not essential, but nice, if you can have t the connections soldered. Protect the wires from bending and breaking by encasing the joints in some RTV (GE silicone goo). I do not understand why the station engineer recommended the Fanfare. This antenna has 0 dB gain. 0 is a very small number. The only advantage to the Fanfare is for external use, since it is self-supporting. An indoor dipole, which can be taped or tacked to any convenient surface, does not need mechanical rigidity. A properly cut dipole has twice the signal strength: 3 dB. ********! Try 0dB (the gain of an antenna is specified wrt a dipole!) |
#10
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Robert Morein wrote:
You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. Hmmm...the website you give above contradicts that. It says: 1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? |
#11
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![]() "ric" wrote in message ... Robert Morein wrote: You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. Hmmm...the website you give above contradicts that. It says: 1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? I'm sorry, Ric. I made a mistake. The folded dipole is cut to 1/4 wavelength, which is why it works out to 33.5 inches for your frequency of interest. |
#12
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On Sat, 25 Jun 2005 18:24:43 -0400, "Robert Morein"
wrote: "ric" wrote in message ... Robert Morein wrote: You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. Hmmm...the website you give above contradicts that. It says: 1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? I'm sorry, Ric. I made a mistake. The folded dipole is cut to 1/4 wavelength, which is why it works out to 33.5 inches for your frequency of interest. ********! 1,2,3,4. . .mistakes. |
#14
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![]() ric wrote: Robert Morein wrote: You can do it yourself. Take a look at http://www.ycars.org/EFRA/Module%20C/AntDip.htm The wavelength of 88.3 mHz is 66.88 inches. Your dipole should be 1/2 that length: 33.5. Hmmm...the website you give above contradicts that. It says: 1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? Ah. you *can* get 6 fters. They are custom parts, though, and not sold at Radio Shack and simmilar places. |
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Joseph Oberlander wrote:
1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? Ah. you *can* get 6 fters. They are custom parts, though, and not sold at Radio Shack and simmilar places. Even the $25 "FM Select" dipole has only a 54" element. That's optimized for 104 MHz. No thanks. http://www.ccrane.com/fm-reflect-antenna.aspx |
#16
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![]() ric wrote: Joseph Oberlander wrote: 1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? Ah. you *can* get 6 fters. They are custom parts, though, and not sold at Radio Shack and simmilar places. Even the $25 "FM Select" dipole has only a 54" element. That's optimized for 104 MHz. No thanks. http://www.ccrane.com/fm-reflect-antenna.aspx Try looking in CB supply stores and also marine equipment. These ultra-long antennas are common on shortwave radios as well. http://www.qsradio.com/QuickSticks.htm 96 inches should be long enough for any application. |
#17
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On Tue, 28 Jun 2005 15:41:39 GMT, Joseph Oberlander
wrote: ric wrote: Joseph Oberlander wrote: 1/2 WL dipole length = 468/f = 468/88.3 = 5.3 feet = 63.6 inches. Since none of the existing FM dipoles I have are 63.6 inches long (the longest being just under 5 feet), should I assume that is why they are so poor in the "college" (88-90 MHz) FM band? Ah. you *can* get 6 fters. They are custom parts, though, and not sold at Radio Shack and simmilar places. Even the $25 "FM Select" dipole has only a 54" element. That's optimized for 104 MHz. No thanks. http://www.ccrane.com/fm-reflect-antenna.aspx Try looking in CB supply stores and also marine equipment. These ultra-long antennas are common on shortwave radios as well. http://www.qsradio.com/QuickSticks.htm 96 inches should be long enough for any application. Sigh. Size isn't everything. Those are HF aerials with blobby things. |
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