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#1
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![]() I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#2
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In article ,
Bruce wrote: As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. My question is what makes you think that these two "dishes" are Parabolas, and not just dish shaped? I would bet that the TV dish will work significantly better than any dish shaped reflector, simply because it will have the correct mathematical shape, and the Focal Point will be defined properly by the designers. -- Bruce in alaska add path after fast to reply |
#3
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posted to rec.boats.electronics
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On Sun, 18 Apr 2010 09:16:26 -0800, Bruce in alaska
wrote: In article , Bruce wrote: As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. My question is what makes you think that these two "dishes" are Parabolas, and not just dish shaped? I would bet that the TV dish will work significantly better than any dish shaped reflector, simply because it will have the correct mathematical shape, and the Focal Point will be defined properly by the designers. I don't particularly think that the cooking dishes have a correct parabolic shape. I was attempting to solve a problem with what I could get my hands on. The discovery of the "cable TV dish" came shortly after I had completed the 17" wok. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#4
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As I stated Bruce, the TV antenna is a good plan. It will be a true parabola and the gain over what you have will be significant.
Don't forget about the 30 degree included angle that is built in. You will have to move the detector up to the center for your application. Steve "Bruce" wrote in message ... I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#5
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posted to rec.boats.electronics
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On Mon, 19 Apr 2010 22:28:25 +0200, "Steve Lusardi"
wrote: As I stated Bruce, the TV antenna is a good plan. It will be a true parabola and the gain over what you have will be significant. Don't forget about the 30 degree included angle that is built in. You will have to move the detector up to the center for your application. Steve No worry about misalignment a there is no "horn" on it. Just a dish :-) It is currently being used as a "roof" for a well pump and I have some 20 ltr. pails that, with a notch cut in one side to clear the piping will work even better so I reckon a trade can be made... once I and them get back to Phuket. "Bruce" wrote in message ... I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#6
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posted to rec.boats.electronics
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Bruce,
I assume you know how to find the parabola's focal point. I won't bore you with a plan if you already know. Let me know if my assumption is incorrect. Steve "Bruce" wrote in message ... On Mon, 19 Apr 2010 22:28:25 +0200, "Steve Lusardi" wrote: As I stated Bruce, the TV antenna is a good plan. It will be a true parabola and the gain over what you have will be significant. Don't forget about the 30 degree included angle that is built in. You will have to move the detector up to the center for your application. Steve No worry about misalignment a there is no "horn" on it. Just a dish :-) It is currently being used as a "roof" for a well pump and I have some 20 ltr. pails that, with a notch cut in one side to clear the piping will work even better so I reckon a trade can be made... once I and them get back to Phuket. "Bruce" wrote in message ... I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#7
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posted to rec.boats.electronics
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On Tue, 20 Apr 2010 09:07:53 +0200, "Steve Lusardi"
wrote: Bruce, I assume you know how to find the parabola's focal point. I won't bore you with a plan if you already know. Let me know if my assumption is incorrect. Steve Yes, have the formula and know about the reflected sunlight method, although that never seemed to work for me as when I put out a piece of paper to measure the reflection it shaded the dish and the reflected beam was too weak to see :-) I'll have to get a special piece of something transparent to use. "Bruce" wrote in message ... On Mon, 19 Apr 2010 22:28:25 +0200, "Steve Lusardi" wrote: As I stated Bruce, the TV antenna is a good plan. It will be a true parabola and the gain over what you have will be significant. Don't forget about the 30 degree included angle that is built in. You will have to move the detector up to the center for your application. Steve No worry about misalignment a there is no "horn" on it. Just a dish :-) It is currently being used as a "roof" for a well pump and I have some 20 ltr. pails that, with a notch cut in one side to clear the piping will work even better so I reckon a trade can be made... once I and them get back to Phuket. "Bruce" wrote in message ... I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) Cheers, Bruce (bruceinbangkokatgmaildotcom) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#8
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Here's a tip. Construct a Tee piece say 2 inch across the top of the tee. Emanating at a 90 degree angle from the center of this 2
inch piece is a straight edge long enough to reach and pass the theoretical focal point....make an educated guess....Mark the center of the parabolic dish with a magic marker. Use a tape measure or fasten a rod of any material perpendicular to the dish center. Place the Tee piece anywhere on the surface of the dish and where the leg of the Tee crosses the center rod is the focal point. Do this several times from different locations on the dish surface and average the crossing point on the perpendicular. Simple. Steve "Bruce" wrote in message ... On Tue, 20 Apr 2010 09:07:53 +0200, "Steve Lusardi" wrote: Bruce, I assume you know how to find the parabola's focal point. I won't bore you with a plan if you already know. Let me know if my assumption is incorrect. Steve Yes, have the formula and know about the reflected sunlight method, although that never seemed to work for me as when I put out a piece of paper to measure the reflection it shaded the dish and the reflected beam was too weak to see :-) I'll have to get a special piece of something transparent to use. "Bruce" wrote in message ... On Mon, 19 Apr 2010 22:28:25 +0200, "Steve Lusardi" wrote: As I stated Bruce, the TV antenna is a good plan. It will be a true parabola and the gain over what you have will be significant. Don't forget about the 30 degree included angle that is built in. You will have to move the detector up to the center for your application. Steve No worry about misalignment a there is no "horn" on it. Just a dish :-) It is currently being used as a "roof" for a well pump and I have some 20 ltr. pails that, with a notch cut in one side to clear the piping will work even better so I reckon a trade can be made... once I and them get back to Phuket. "Bruce" wrote in message ... I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) Cheers, Bruce (bruceinbangkokatgmaildotcom) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#9
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Bruce wrote in
: I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) http://www.turnpoint.net/wireless/has.html http://www.oreillynet.com/cs/weblog/view/wlg/448 http://binarywolf.com/249/pringles_cantenna.htm http://www.netscum.com/~clapp/wireless.html http://www.seattlewireless.net/PringlesCantenna We get about 1.5 miles range from my 200mw hotspot with a 6db antenna 15 meters up in a tree. The whole hotspot is built into an inverted plastic bucket. The pringle's can antennas are very directional and great for point to point work like you're doing.....and can be built and rebuilt for nothing. -- Creationism is to science what storks are to obstetrics. Larry |
#10
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On Tue, 20 Apr 2010 01:45:27 +0000, Larry wrote:
Bruce wrote in : I ended up building two wi-fi parabolic antenna. the first a 300 mm screen-wire dipper (used for frying bananas) measured 300 mm in diameter and about 90 mm deep. Later built a second dish using a 430 mm aluminum "wok" about 100 mm deep. The first antenna gave a better signal then the adapter but the second antenna gave, using the instruments available to me, approximately 3 times the signal that the bare wi-fi "adapter" had. As I previously mentioned I do not have a signal strength meter and used the standard Linux utility "iwconfig" to produce some sort of data. It gave a reading of 6 for signal strength using the bare adapter and as high as 23 with the wok I can only assume that whatever the value of the increments that the ratio is accurate. As luck would have it, I found an abandoned TV "cable" antenna - as used here "cable" is received on a 3 foot dia. parabolic antenna and I will probably try that at some later date. Cheers, Bruce (bruceinbangkokatgmaildotcom) http://www.turnpoint.net/wireless/has.html http://www.oreillynet.com/cs/weblog/view/wlg/448 http://binarywolf.com/249/pringles_cantenna.htm http://www.netscum.com/~clapp/wireless.html http://www.seattlewireless.net/PringlesCantenna We get about 1.5 miles range from my 200mw hotspot with a 6db antenna 15 meters up in a tree. The whole hotspot is built into an inverted plastic bucket. The pringle's can antennas are very directional and great for point to point work like you're doing.....and can be built and rebuilt for nothing. I was going to built a tin can antenna but the devil is in the details and so far I haven't been able to locate the tiny coax connectors that connect to the wi-fi adapter and as I had read that at wi-fi frequencies the loss in the usually available cable is nearly equal to the gain of the antennas I have been a bit reluctant to try. I am making a trip down to the "electronic district" tomorrow and, after having written the above, will undoubtedly discover a source of not only the connectors but also a coil of low loss cable that I can get free :-) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
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