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#1
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My office is located in a metal warehouse type structure which
effectively shields us from most outside signals. If I want to listen to the radio or use my cell phone inside the building I have to open a bay door. Is there a way I can get all those radio waves inside the building without opening the doors. Is it possible to place an antenna outside and have everything rebroadcast inside? The main reason for this approach is the cell phone. It would be kind of impractical to run an antenna from my cell phone to the outdoors. Barring the rebroadcasting idea, I am still interested in what the best way is to get better reception on the radio. Do I need to run a wire outside or somehow ground the radio. Go easy on me, I've heard some stuff about 7mhz being 23 feet long at a quarter wave. If your gonna spring some of that stuff on me I need a little more detailed information. I'm not up on radio lingo but I am technically capable. TIA The Bad Priest |
#2
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My office is located in a metal warehouse type structure which
effectively shields us from most outside signals. If I want to listen to the radio or use my cell phone inside the building I have to open a bay door. Is there a way I can get all those radio waves inside the building without opening the doors. Is it possible to place an antenna outside and have everything rebroadcast inside? The main reason for this approach is the cell phone. It would be kind of impractical to run an antenna from my cell phone to the outdoors. Barring the rebroadcasting idea, I am still interested in what the best way is to get better reception on the radio. Do I need to run a wire outside or somehow ground the radio. Go easy on me, I've heard some stuff about 7mhz being 23 feet long at a quarter wave. If your gonna spring some of that stuff on me I need a little more detailed information. I'm not up on radio lingo but I am technically capable. While it may not work for you , look up "passive repeater" This is an antenna aimed at the desired station (on the outside of the building in your case) and a feedline inside the building hooked to another antenna. For receiving other frequencies you may have to run a wire outside the building and either hook it to the receiver or wrap it around the receiver. I have not seen it but have heard that in long tunnels they have an outside antenna and an amplifier and some inside antennas for the FM radio stations. |
#3
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The passive repeater is an excellent idea. I have done that extensively at
Radio Shack. We had a TV antenna outside for the TV signals. We would be sure to run a feed-line to the inside TV demo antenna, and to a automobile antenna in the "car sound" display. We could then give relatively accurate demonstrations of the small transistor radios and auto stereos. You wouldn't believe it, or won't believe it until you try it. Two antennas connected by as sort a feed-line as possible. -- 73 es cul wb3fup a Salty Bear "Ralph Mowery" wrote in message ... My office is located in a metal warehouse type structure which effectively shields us from most outside signals. If I want to listen to the radio or use my cell phone inside the building I have to open a bay door. Is there a way I can get all those radio waves inside the building without opening the doors. Is it possible to place an antenna outside and have everything rebroadcast inside? The main reason for this approach is the cell phone. It would be kind of impractical to run an antenna from my cell phone to the outdoors. Barring the rebroadcasting idea, I am still interested in what the best way is to get better reception on the radio. Do I need to run a wire outside or somehow ground the radio. Go easy on me, I've heard some stuff about 7mhz being 23 feet long at a quarter wave. If your gonna spring some of that stuff on me I need a little more detailed information. I'm not up on radio lingo but I am technically capable. While it may not work for you , look up "passive repeater" This is an antenna aimed at the desired station (on the outside of the building in your case) and a feedline inside the building hooked to another antenna. For receiving other frequencies you may have to run a wire outside the building and either hook it to the receiver or wrap it around the receiver. I have not seen it but have heard that in long tunnels they have an outside antenna and an amplifier and some inside antennas for the FM radio stations. |
#4
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On Thu, 28 Aug 2003 12:42:15 -0400, "Ralph Mowery"
wrote: While it may not work for you , look up "passive repeater" This is an antenna aimed at the desired station (on the outside of the building in your case) and a feedline inside the building hooked to another antenna. In most cases you have to be quite close to the indoor antenna (within a few meters), since the signal reradiated from the indoor antenna is suffering an additional inverse square attenuation. The worst situation for a passive repeater system is when the repeater is in the mid path with the end stations A and B. The path losses (expressed in decibels) from A to the repeater and from the repeater to B are _added_. Compare this to the free space (line of sight situation) in which the total path loss from A and B is only 6 dB more than compared to the path loss for A to the mid point repeater location. In a passive repeater system, moving the repeater closer to the other station, the sum of the path losses from A to the repeater and from the repeater to B (expressed in decibels) will be smaller than with a repeater in the mid path. I have not seen it but have heard that in long tunnels they have an outside antenna and an amplifier and some inside antennas for the FM radio stations. Leaky coaxial lines are used as "antennas" in tunnels. Paul OH3LWR |
#5
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I've never had any luck using just one can. You could tie the string to a
doorknob and use just one can - but what are you going to hear on it? To make it work, have another can on the far end of the string, with someone speaking clearly into the can. Remember to keep the audio transmission line taut for best reception. Charles Brabham, N5PVL |
#6
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Your tin can will work much better if you add a piece of tissue a coil
of wire and a magnet. I don't know why no one ever mentions that when talking about the finer points of tin can technology. Well I guess a passive repeater was exactly what I was thinking of and it sounds like it works about as well as one would expect. Is there such a thing as an active repeater? Is there some way that I can amplify all of those signals. Can I broadcast all frequencies all the time? Also, I'm still interested in grounding. I've been noticing the effects of grounding more and more lately. I just realized that my house isn't really grounded (as far as I can tell anyway). I've got PVC plumbing and the electric box is just wired neutral to common. Ever since I put a ball on my truck and wired up the trailer light connecter I've gone from great reception on the radio to average or poor. I think the trailer ground wire is acting like a maverick antenna. We got a new forklift that has a fiber strap that drags along the floor. I think the wheels are polyethelene or polypropoline or something and without the strap the forklift can generate enough static electricity to knock you on your ass. I lived in Okinawa when I was a kid and a lot of the cars there had a rubber strap with a little reflector that drug along the ground. The explanation at the time was that the Japanese liked lights. I never did understand but could it be to ground the vehicle and get better radio reception? Should I drag a chain behind my truck for better reception? Also, the radio at work; how should I set the antenna up. It's just two pieces of wire tucked up into the ceiling tile. There is a copper compressed air line running nearby that is not grounded directly (It is hung from the structual steel but there is no direct copper to ground). I've noticed that sometimes reception is a lot better if one or both ends of the wire are touching this copper line. Is the antenna being grounded or is it acquiring capacitance? WHat is the proper way to ground it. Do you ever ground an antenna or do you just ground the receiver? Well that's probably too many questions already. I'm posting via google so i have to wait 3 to 6 hours to see it. Thanks, El Malo and not that anyone is going to tell me but what is 73? |
#7
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El Malo,
The 'static' strap draggin on the ground is a terrible idea. In most cases, it generates more static than it will ever 'cure'. It's also dangerous, just like the fork lift. The DOT prohibits static straps on commercial vehicles that carry flamable/explosive materials (fuel trucks) because they act as part of a "VanDegraff"(sp) generator. I'm sure a nice fat spark is exactly what you want to see when connecting a fuel line to a tank. (Also why fuel hoses at gas pumps are grounded through the nozzle. And why fuel trucks at an air- port always connect a ground line to the plane before fueling.) 'Doc |
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