Home |
Search |
Today's Posts |
|
#1
![]() |
|||
|
|||
![]()
dittos
"Sal M. Onella" wrote in message news ![]() "JoeSch" wrote in message ... Thank you all for replying. Sorry to take so long to get back here. I momentarily put the project aside because, after missing the first game, (I posted the first message about an hour before game time, lol), the Jets will be carried on my cable stations for the next two weeks. Add the bye week into that and I had a couple of weeks to get this thing together-there was no super-immediate rush. But I am going to build this in the next week or so. As far as Channel 2 going to UHF in February, the Jets regular season ends in December, so an antenna that is useful until February will take of this season nicely. Any post season playoff games by the Jets, (should they get into the playoffs), will be broadcast nationally, so I won't need the antenna for that. I'll worry about next season when it happens. However, don't be surprised if next September you see a thread about building a UHF antenna for the new Channel 2 New York. I have high hopes for this project giving me some kind of watchable, albeit possibly snowy signal. Here's why. Several years ago I dangled a piece of twin lead from my second floor window to the ground and got both the sound and an extremely, extremely snowy picture of Channel 4 New York, (which carried the Jets at that time). The house I lived in was a few miles farther inland than the one I lived in now, and it was just a simple 12 foot piece of twin lead out the window, but I got SOMETHING. Ths project will be on a pole, on a roof, on a house closer to the water using an antenna scientifically optimized for Channel 2, so I think the chances of getting something watchable are very good. There must be something more at play here than just "line-of-sight" from here to the Empire State Building, at least at this frequency. Besides, friends driving down to New York tell me that they pick up FM stations on their car radios about 20 miles down the road from here. FM frequencies are a little bit higher, (therefore more straight line), than Channel 2. Though the requirements for FM reception and TV reception are not the same, it still indicates that I am not too far out of range for this frequency. I have found an interesting project from the US Patent Office, so it is between that and Sal's Yagi. I am leaning toward the Yagi, so I will be back with more questions in the next day or two. Just a few questions: A) What is the gain of Sal's Yagi compared to a single dipole? SAL ADDS: YOU'LL GET GAIN OF SIX TO EIGHT DB (NOT SHOUTING. USING CAPS TO OFFSET, SINCE THE STUPID PROGRAM DIDN'T MAKE THE RIGHT MARKS.) B) In sound, there is a rule for Sound Pressure Level which says "double the distance, 6 dB down in decibels". In other words, If I have a Sound Pressure Level of 100 dB at ten feet, if I move back to twenty feet my SPL goes down to 94 decibels. Does a similar rule apply to antenna reception, that if get good reception with a certain antenna from 50 miles away, I need an antenna 6 dB more sensitive to get similar reception from 100 miles away? IT'S WORSE THAN THAT, UNFORTUNATELY, SINCE THE SIGNAL DOESN'T BEND MUCH AROUND THE EARTH'S CURVATURE. IT WOULD BE TRUE FOR DISTANCES OF 5 AND 10 MILES, RESPECTIVELY, SINCE THE EARTH'S CURVATURE DOESN'T COME INTO PLAY AT THOSE DISTANCES. (YOUR SOURCE IS ABOUT 1200 FT UP IN THE AIR.) A PHENOMENON CALLED "DUCTING" WILL SOMETIMES TRUMP THE EARTH'S CURVATURE. TV SIGNALS CAN GET TRAPPED IN ATMOSPHERIC LAYERS AND BE RETURNED TO EARTH MUCH STRONGER THAN THE THEORY PREDICTS. DUCTS ARE MORE COMMON IN WARM AIR, SO FOOTBALL SEASON IN THE NORTHEAST IS NOT THE TIME TO BE HOPING FOR DUCTING. FOR WHAT IT'S WORTH, WCBS-2 IS ALREADY SENDING OUT ITS DIGITAL SIGNAL IN ADVANCE OF NEXT FEBRUARY -- MOST STATIONS ARE DOING SO. WCBS IS ON CHANNEL 56 NOW AND WILL DROP TO 33 ON TRANSITION DAY. SEE http://rabbitears.info/market.php IT IS CONCEIVABLE THAT A BIG UHF ANTENNA WOULD WORK FOR YOU. IT WORKS FOR ME, HERE IN SOUTHERN CALIFORNIA, BUT MY DISTANT TRANSMITTERS ARE ON A 6,000 FT MOUNTAINTOP, WHICH IS A SIGNIFICANT ADVANTAGE FOR ME. "SAL" |
#2
![]() |
|||
|
|||
![]()
On Tue, 16 Sep 2008 18:21:22 -0700, "Sal M. Onella"
wrote: MY DISTANT TRANSMITTERS ARE ON A 6,000 FT MOUNTAINTOP, WHICH IS A SIGNIFICANT ADVANTAGE FOR ME. Hi Joe, The impact of this statement is that with the transmitter antenna that high, it can see to an horizon (edge of the viewable earth) that is 109 miles away. This is just the situation you need if your receive antenna was sitting on the ground. Unfortunately, the Empire State Building is not that tall (1200 feet or so), and it is effectively (from your point of view, literally) underground by that needed additional 4800 feet. To make up the difference, you would lift that antenna off the ground, and try to raise it that same 4800 feet. Unlikely. A gain antenna will not make up for looking through 100 miles of mud and water. On the flip side, if ducting is working (don't make a schedule based on this coinciding with your calendar), rabbit ears on your roof will do nicely. Myself, during the summer months in Colorado, I could get Edmonton and Calgary Canada - more than 1000 miles away. Getting them on separate occasions was more a surprise than a plan, however. But I did manage to get to see an entire movie before the duct collapsed. A simple question that hasn't been addressed: What do you see when you tune NYC stations? 73's Richard Clark, KB7QHC |
#3
![]() |
|||
|
|||
![]() "JoeSch" wrote in message ... I apologize for making this about TV reception instead of radio, but I did not know where to turn. I live in Connecticut, about 100 miles from New York City, (102 miles by the lattitude-longitude charts) and I am about a block from the water, Long Island Sound. I grew up in New York and am a NY Jets and Giants fan, which is broadcast from the Empire State building. The Giants' games are carried by one network, but the other Connecticut stations only carry Patriots games, not the Jets. The Jets' games are carried on channel 2 New York, which is 102 miles as the crow flies from my house. Football packages on satellite TV are beyond present financial condition. I only care about channel 2, New York. Does anyone have any ideas for a quick rooftop antenna I can put on a pole and run into my house for the Jets game? I really don't mind if the signal is somewhat snowy as long as I can make out what is happening on the field-beats radio. Besides, this is football- sometimes it snows for real and nobody complains, lol. Anyway, any help would be greatly appreciated. PS: I have seen websites for dipole antennas. My second question is: If I make a dipole antenna, what if I mounted it on a piece of cardboard or styrofoam for it's length, which cardboard or styrofoam has aluminum foil on the reverse side? The aluminum foil would not contact the dipole, and be separated from it by one quarter to one inch, depending on material thickness. The reason I ask is if this will cut off 180 degrees of reception, thereby improving the signal to noise ratio, (I know a little about electronics as an audio hobbyist, but very little about antennas even though I have tried to get a grasp). Quick would be a rabbit ears set on the roof. Space your reflector at some distance so that your antenna and reflector look more like an H. What you really want though is a Rhombic antenna. Google that. It is a diamond shaped wire antenna with some real gain. |
#4
![]() |
|||
|
|||
![]()
On Sun, 7 Sep 2008 07:25:59 -0700 (PDT), JoeSch
wrote: I live in Connecticut, about 100 miles from New York City, (102 miles by the lattitude-longitude charts) and I am about a block from the water, Long Island Sound. I grew up in New York and am a NY Jets and Giants fan, which is broadcast from the Empire State building. Hi Joe, The long answer is No. The short answer is that with the transmission antenna at 1250 feet (give or take), it sees out to an horizon 25 miles away. An antenna on the ground there would receive its signal, but you would have to lift it as you pushed back. By the time you pushed back another 25 miles, that receiving antenna would also have to be 1250 feet in the air. That is only 50 miles range for a very unlikely audience. You are challenge by an additional 50 miles, which, from your perspective, places the top of the Empire State building beneath the earth's surface by a considerable depth. No amount of amplification will rescue that situation. 73's Richard Clark, KB7QHC |
#5
![]() |
|||
|
|||
![]()
On Sun, 07 Sep 2008 09:47:26 -0700, Richard Clark
wrote: On Sun, 7 Sep 2008 07:25:59 -0700 (PDT), JoeSch wrote: I live in Connecticut, about 100 miles from New York City, (102 miles by the lattitude-longitude charts) and I am about a block from the water, Long Island Sound. Hi Joe, If you are a betting man, this frequency has a reputation for world wide reception.... if. It is an exotic topic, and you might astound yourself with seeing the game, but don't invite the crew over expecting to happen. The odds are strictly for Vegas as this exotic topic is called tropospheric scattering, or ducting, or meteor shower DX, or any other number of long-shot methods. 73's Richard Clark, KB7QHC |
#6
![]() |
|||
|
|||
![]()
Easiest and probably the cheapest is to buy a radio shack deep fringe
antenna. A chimeny or Eve mount should be the easiest, it not feasible a 20 foot piece of 1" steel pipe would do nicely. I got denver stations in cheyenne in the 50-60s with a winegard antenna on a 20 foot pole. Transmitters were on lookout mountain or so I was told..... Channel Master and Wingard are two other great tv antenna manufacuters. "JoeSch" wrote in message ... I apologize for making this about TV reception instead of radio, but I did not know where to turn. I live in Connecticut, about 100 miles from New York City, (102 miles by the lattitude-longitude charts) and I am about a block from the water, Long Island Sound. I grew up in New York and am a NY Jets and Giants fan, which is broadcast from the Empire State building. The Giants' games are carried by one network, but the other Connecticut stations only carry Patriots games, not the Jets. The Jets' games are carried on channel 2 New York, which is 102 miles as the crow flies from my house. Football packages on satellite TV are beyond present financial condition. I only care about channel 2, New York. Does anyone have any ideas for a quick rooftop antenna I can put on a pole and run into my house for the Jets game? I really don't mind if the signal is somewhat snowy as long as I can make out what is happening on the field-beats radio. Besides, this is football- sometimes it snows for real and nobody complains, lol. Anyway, any help would be greatly appreciated. PS: I have seen websites for dipole antennas. My second question is: If I make a dipole antenna, what if I mounted it on a piece of cardboard or styrofoam for it's length, which cardboard or styrofoam has aluminum foil on the reverse side? The aluminum foil would not contact the dipole, and be separated from it by one quarter to one inch, depending on material thickness. The reason I ask is if this will cut off 180 degrees of reception, thereby improving the signal to noise ratio, (I know a little about electronics as an audio hobbyist, but very little about antennas even though I have tried to get a grasp). |
#7
![]() |
|||
|
|||
![]() "JoeSch" wrote in message ... I apologize for making this about TV reception instead of radio, but I did not know where to turn. I live in Connecticut, about 100 miles from New York City, (102 miles by the lattitude-longitude charts) and I am about a block from the water, Long Island Sound. I grew up in New York and am a NY Jets and Giants fan, which is broadcast from the Empire State building. The Giants' games are carried by one network, but the other Connecticut stations only carry Patriots games, not the Jets. The Jets' games are carried on channel 2 New York, which is 102 miles as the crow flies from my house. Football packages on satellite TV are beyond present financial condition. I only care about channel 2, New York. Does anyone have any ideas for a quick rooftop antenna I can put on a pole and run into my house for the Jets game? I really don't mind if the signal is somewhat snowy as long as I can make out what is happening on the field-beats radio. Besides, this is football- sometimes it snows for real and nobody complains, lol. Anyway, any help would be greatly appreciated. PS: I have seen websites for dipole antennas. My second question is: If I make a dipole antenna, what if I mounted it on a piece of cardboard or styrofoam for it's length, which cardboard or styrofoam has aluminum foil on the reverse side? The aluminum foil would not contact the dipole, and be separated from it by one quarter to one inch, depending on material thickness. The reason I ask is if this will cut off 180 degrees of reception, thereby improving the signal to noise ratio, (I know a little about electronics as an audio hobbyist, but very little about antennas even though I have tried to get a grasp). First of all, don't introduce any other metallic objects (foil, etc). Just the elements described below. You need to make a basic yagi antenna. When finished, it greatly resembles a TV antenna, except the elements are all nearly the same size, optimized for Channel 2. (Neglecting the fact that WCBS digital TV is on a UHF channel. You asked for analog WCBS-TV, Channel 2.) Fabricate a folded dipole for 57 MHz out of regular TV twinlead. He http://www.wfu.edu/~matthews/misc/dipole.html Looks like he uses Channel 2 as an example -- convenient! He says it's 2.5 meters long -- I think that's about 98.4 inches Probably should mount it on an 8-foot piece of 1 X 2 wood to keep it straight and level. An inch or so will stick out at the ends -- no big deal. It will go on the roof, mounted crossways on another piece of wood called a "boom" which is aligned to New York City. The folded dipole's position on the boom should be about 2 feet from the end that will be away from New York. That is the active or "driven" element of the yagi and it needs some helpers. The helpers are made of ordinary metal tubes, but have no direct electrical connection to the driven element. Old aluminum tubing is fine. Assorted pieces of old TV antennas will work if the pieces are tightly fastened together and carefully cleaned at the attaching points for a good connection. One helper is called a "reflector" Make it 6 percent longer than the driven element and mount it on the boom behind the driven element (away from New York) by about 21 inches. Next helper is called "Director #1." It's 1% shorter than the driven element and it's mounted on the boom 21 inches in front of the driven element, toward New York. Next helper is called "Director #2." It's 8% shorter than the driven element and it's mounted 37 inches in front of Director #1. You can add more directors, same length, same spacing as #2, but they won't capture a lot more signal after the first few. Plus, with more than two directors, the boom gets really, really long. Note that this antenna is a 300-ohm antenna. Since your TV input is probab ly NOT 300 ohms, you have to transform the impedance to the 75-ohm coaxial cable that plugs into the TV. Do that near your antenna. What I mean is this: Have only about a foot or so of 300 ohm twinlead coming down from the folded dipole. Connect a 300/75 ohm transformer or "balun" at that point and run coaxial cable the rest of the way to the TV. Much better for interference rejection, especially at Channel 2. Such 300/75 ohm baluns are available at all radio stores as well as many variety, drug and department stores. Buy whatever one you think you can connect with the tools at hand. You may have a balun or two that came with an old TV or VCR. The first one of these I ever helped build was made with coathangers on a broomstick for Channel 13. (Higher freq meant smaller elements -- easier.) It worked fine. Let us know how this works for you. I'm interested to know if you were able to follow what I wrote. |
#8
![]() |
|||
|
|||
![]() "JoeSch" wrote in message ... I apologize for making this about TV reception instead of radio, but I did not know where to turn. I live in Connecticut, about 100 miles from New York City, (102 miles by the lattitude-longitude charts) and I am about a block from the water, Long Island Sound. I grew up in New York and am a NY Jets and Giants fan, which is broadcast from the Empire State building. The Giants' games are carried by one network, but the other Connecticut stations only carry Patriots games, not the Jets. The Jets' games are carried on channel 2 New York, which is 102 miles as the crow flies from my house. Football packages on satellite TV are beyond present financial condition. I only care about channel 2, New York. Does anyone have any ideas for a quick rooftop antenna I can put on a pole and run into my house for the Jets game? I really don't mind if the signal is somewhat snowy as long as I can make out what is happening on the field-beats radio. Besides, this is football- sometimes it snows for real and nobody complains, lol. Anyway, any help would be greatly appreciated. PS: I have seen websites for dipole antennas. My second question is: If I make a dipole antenna, what if I mounted it on a piece of cardboard or styrofoam for it's length, which cardboard or styrofoam has aluminum foil on the reverse side? The aluminum foil would not contact the dipole, and be separated from it by one quarter to one inch, depending on material thickness. The reason I ask is if this will cut off 180 degrees of reception, thereby improving the signal to noise ratio, (I know a little about electronics as an audio hobbyist, but very little about antennas even though I have tried to get a grasp). First of all, don't introduce any other metallic objects (foil, etc). Just the elements described below. You need to make a basic yagi antenna. When finished, it greatly resembles a TV antenna, except the elements are all nearly the same size, optimized for Channel 2. (Neglecting the fact that WCBS digital TV is on a UHF channel. You asked for analog WCBS-TV, Channel 2.) Fabricate a folded dipole for 57 MHz out of regular TV twinlead. He http://www.wfu.edu/~matthews/misc/dipole.html Looks like he uses Channel 2 as an example -- convenient! He says it's 2.5 meters long -- I think that's about 98.4 inches Probably should mount it on an 8-foot piece of 1 X 2 wood to keep it straight and level. An inch or so will stick out at the ends -- no big deal. It will go on the roof, mounted crossways on another piece of wood called a "boom" which is aligned to New York City. The folded dipole's position on the boom should be about 2 feet from the end that will be away from New York. That is the active or "driven" element of the yagi and it needs some helpers. The helpers are made of ordinary metal tubes, but have no direct electrical connection to the driven element. Old aluminum tubing is fine. Assorted pieces of old TV antennas will work if the pieces are tightly fastened together and carefully cleaned at the attaching points for a good connection. One helper is called a "reflector" Make it 6 percent longer than the driven element and mount it on the boom behind the driven element (away from New York) by about 21 inches. Next helper is called "Director #1." It's 1% shorter than the driven element and it's mounted on the boom 21 inches in front of the driven element, toward New York. Next helper is called "Director #2." It's 8% shorter than the driven element and it's mounted 37 inches in front of Director #1. You can add more directors, same length, same spacing as #2, but they won't capture a lot more signal after the first few. Plus, with more than two directors, the boom gets really, really long. Note that this antenna is a 300-ohm antenna. Since your TV input is probab ly NOT 300 ohms, you have to transform the impedance to the 75-ohm coaxial cable that plugs into the TV. Do that near your antenna. What I mean is this: Have only about a foot or so of 300 ohm twinlead coming down from the folded dipole. Connect a 300/75 ohm transformer or "balun" at that point and run coaxial cable the rest of the way to the TV. Much better for interference rejection, especially at Channel 2. Such 300/75 ohm baluns are available at all radio stores as well as many variety, drug and department stores. Buy whatever one you think you can connect with the tools at hand. You may have a balun or two that came with an old TV or VCR. The first one of these I ever helped build was made with coathangers on a broomstick for Channel 13. (Higher freq meant smaller elements -- easier.) It worked fine. Let us know how this works for you. I'm interested to know if you were able to follow what I wrote. |
#9
![]() |
|||
|
|||
![]() "Sal M. Onella" wrote in message ... "JoeSch" wrote in message ... snip Does anyone have any ideas for a quick rooftop antenna I can put on a pole and run into my house for the Jets game? I really don't mind if the signal is somewhat snowy as long as I can make out what is happening on the field-beats radio. Besides, this is football- sometimes it snows for real and nobody complains, lol. snip You need to make a basic yagi antenna. When finished, it greatly resembles a TV antenna, except the elements are all nearly the same size, optimized for Channel 2. ( snip I posted the instructions for a Channel 2 Yagi a few weeks ago. They were acknowledged and I've been waiting anxiously for some feedback. Curiosity got the better of me this afternoon, so I built the thing myself -- exactly as described except for the second director, since I was losing the light and three elements proved the point. With just the folded dipole at ten feet, I got a recognizable KCBS picture from 124 miles. Bad snow, noisy sound and no color. Joe, a dedicated Jets fan, would watch this picture but his girl friend would not. When I added the reflector, the snow and the sound got better. When I put it up to fifteen feet I had color. When I added the first director and returned it to fifteen feet, the snow got a lot less and the picture was quite watchable. The girl friend would say, "Gee, Honey, that's a pretty good picture. Can we get free HBO, too?" (They never understand ... never.) I measured the signal with my old analog signal level meter and got negative 16 dBmV, which looked about right. Another director should add only a dB or two. Maybe I will try a preamp and see what that does. Trouble is, Channel 2 suffers from impulse noise (electrical appliances are usually the cause). Antenna would need to be elevated to reduce that problem. WCBS has an insignificant 1 dB more power than KCBS but their antenna height is a lot less, which impacts Joe in Connecticut. However, his distance is less, 100 miles vs. 124 miles. "Sal" |
#10
![]() |
|||
|
|||
![]() "Sal M. Onella" wrote in message ... "Sal M. Onella" wrote in message ... "JoeSch" wrote in message ... snip Does anyone have any ideas for a quick rooftop antenna I can put on a pole and run into my house for the Jets game? I really don't mind if the signal is somewhat snowy as long as I can make out what is happening on the field-beats radio. Besides, this is football- sometimes it snows for real and nobody complains, lol. snip You need to make a basic yagi antenna. When finished, it greatly resembles a TV antenna, except the elements are all nearly the same size, optimized for Channel 2. ( snip I posted the instructions for a Channel 2 Yagi a few weeks ago. They were acknowledged and I've been waiting anxiously for some feedback. Curiosity got the better of me this afternoon, so I built the thing myself -- exactly as described except for the second director, since I was losing the light and three elements proved the point. With just the folded dipole at ten feet, I got a recognizable KCBS picture from 124 miles. Bad snow, noisy sound and no color. Joe, a dedicated Jets fan, would watch this picture but his girl friend would not. When I added the reflector, the snow and the sound got better. When I put it up to fifteen feet I had color. When I added the first director and returned it to fifteen feet, the snow got a lot less and the picture was quite watchable. The girl friend would say, "Gee, Honey, that's a pretty good picture. Can we get free HBO, too?" (They never understand ... never.) I measured the signal with my old analog signal level meter and got negative 16 dBmV, which looked about right. Another director should add only a dB or two. Maybe I will try a preamp and see what that does. Trouble is, Channel 2 suffers from impulse noise (electrical appliances are usually the cause). Antenna would need to be elevated to reduce that problem. WCBS has an insignificant 1 dB more power than KCBS but their antenna height is a lot less, which impacts Joe in Connecticut. However, his distance is less, 100 miles vs. 124 miles. "Sal" A 3el 6m yagi would work very well, all you need is a 50 ohm to 75 ohm adapter @ about 20 feet. Use a small TV rotator, and when your not watching ch2 you can try calling CQ on 6m. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Car and Rooftop Antennas | Scanner | |||
Quick All-in-One Vertical Antenna and Air Core MatchingTransformer and It's a Slinky ! | Shortwave | |||
rooftop verticals vs. ground plane | CB | |||
Rooftop tower FS | Swap | |||
Rooftop Tower FS | Swap |