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My posts havent been gittin through fer some reason so I'm gonna
repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? |
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Parallax wrote:
My posts havent been gittin through fer some reason so I'm gonna repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? Don't key the VHF if the cell phone is plugged in! In fact, it might not be a good idea have the VHF on or connected. Doubt it'll help much, if at all. There was a good thread maybe a year ago about boosting cellphone distances. There are both directional antennas and power boosters. Do a google on Cell phone antennas, as I recall. -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
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That's the dumbest thing I've seen in a long time!.....and will
destroy BOTH radio and cellphone....DON'T DO IT! 1 - Antenna will not transmit 800 or 1900 Mhz..... 2 - The transmitter of one radio transmits into the RECEIVER of the other, destroying its sensitive input amplifier. 3 - The transmitters, themselves, will be operating into such a complex impedance, it may take out the output amp in the transmitter, too! NO GO....... Don't feel pregnant, though. Today I was helping someone troubleshoot their electrical problems on a motor yacht. I casually asked him why his battery charger was connected to his 2000W AC inverter. Without missing a beat and totally serious, he told me that was to keep his battery charged when he was at anchor away from the dock....... Ever seen a perpetual motion machine?.....(c; I just said, "Oh, I see.".....thinking about how I was gonna get away from this boat before I found its exhaust riser plugged into the diesel intakes to conserve air...... Sure hope his head doesn't pump into the fresh water tank....hee hee. The inverter had plenty of power to run the 30A battery charger plugged into it, though.....(c; On 27 Oct 2003 15:39:00 -0800, (Parallax) wrote: My posts havent been gittin through fer some reason so I'm gonna repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? Larry W4CSC "Very funny, Scotty! Now, BEAM ME MY CLOTHES! KIRK OUT!" |
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Why don't you just get a cell phone antenna and if needed, an amplifier? With a 4 foot
antenna on the stern rail we had contact with ATT for the entire East Coast. The only problem area was Maine, where the coves can be blocked by hills. BTW, one of the proposals for "next generation" cell technology was by a company that specializes in small supercomputers for Defense Dept. radar and sonar systems. The same technology that can "aim" radar can be used to aim cell bandwidth to the customer that needs it at the moment. "Parallax" wrote in message om... (Parallax) wrote in message . com... My posts havent been gittin through fer some reason so I'm gonna repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? OK, an even worse idea.......Use your radar (I dont have one) as a high gain antenna to point toward a cell tower. It ought to work for 900 Mhz. Some electronics could figger out the direction to the best tower. |
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1) Cell phone amplifiers exist, work, and are legal. see
http://www.digitalantenna.com/cellamp.html 2) The VHF antenna idea won't work and might, as noted above, destroy the cell phone. 3) The radar antenna idea actually has some technical merit, but the challenge of actually getting the radar to point to the right place, and hooking up the cell phone to its feed without significant insertion loss, make it pretty much impossible. It would also be illegal, as it would not be type accepted. 4) A cell phone antenna at the masthead is your best bet. West Marine sells them. For good ones, see: http://www.digitalantenna.com/cell.html Jim Woodward www.mvFintry.com (Parallax) wrote in message . com... My posts havent been gittin through fer some reason so I'm gonna repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? |
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On 27 Oct 2003 15:39:00 -0800, (Parallax) wrote
(with possible editing): My posts havent been gittin through fer some reason so I'm gonna repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? NO! Don't do it! 1. VHF radio WILL destroy cell phone receiver. 2. Cell phone transmitter WILL NOT match the VHF antenna resulting in mostly reflected power. That could damage the cellular phone. 3. If you COULD use the same antenna (which you can't), the only safe way would be to switch it to the transceiver in use while applying a dummy load to the unused transceiver. 4. Some cellular phones are analog which uses the 800 mhz band, and others are digital which uses the 1900 mhz band. Still others work on both bands. Also, don't use marine radar antenna. Radar operates at different frequency than cell phones. They are not harmonically related. You CAN legally use a booster amplifier (they are manufactured typically for installation in a car. That can boost the 0.10 - 0.15 or so watts from the typical cell phone to 3 watts. Mount the antenna as high up as you can, but do not extend the feedline from what is supplied with the kit. The reason is twofold: 1) the amp is based on effective radiated power which includes the loss on a feedline, and 2) unless you get very good cable, you will lose more in feedline loss than you gain from height, particularly on the 1900 mhz band. You could use a directional antenna, but, so far as I know, they are not legal for that type use. That's worth a check, though, as I believe they are considered legal for use in security systems and it's been a while since I looked at those regulations. http://www.fcc.gov -- Larry W1HJF Email to rapp at lmr dot com |
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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 On 27 Oct 2003 15:39:00 -0800, Parallax wrote: My posts havent been gittin through fer some reason so I'm gonna repost this one. For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 Put a T in the output of your VHF so your cellphone can be connected to your VHF antenna waaaaaaaaay up thar on your mast. Since your 900 Mhz cellphone is even more line-of-sight than vhf, this will give you more more coverage when you are a few miles out. In this case, I expect coverage will then be limited by cellphone power instead of by not being able to see a tower. I would expect to be able to get coverage from 15 miles out. I once experimented, while standing on my cabin top, I was able to use my cell phone while being 6 miles offshore. Would a cell phone booster be illegal? Wrong kind of antenna, most Cell phones are 800-900MHz, PCS is around 1.2GHz IIRC, and some are 1.8GHz. The VHF antenna, is expecting to see about 150MHz. Bast case scenario, it simply doesn't work. If you were so unfortunate as to key up the VHF while it was connected, that acrid smell you'd experience, would be the death throes of the the cell phone. THat's without getting into the whole issue of impedence mismatch. In short, don't even go there. Get a booster, buy a type approved one, and you'll be fine. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/n1DVd90bcYOAWPYRAn0iAJwPNTQnx9XhdNIMNlp9SxalrnzQPw Cg5kam yLS6xkLP/nF3mQkEm83+kz0= =cnWj -----END PGP SIGNATURE----- -- Jim Richardson http://www.eskimo.com/~warlock If ignorance is bliss, why aren't more people happy? |
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Hash: SHA1 On Tue, 28 Oct 2003 16:18:57 -0500, Rodney Myrvaagnes wrote: On 28 Oct 2003 05:05:13 -0800, (Parallax) wrote: I never said I had good ideas. However, I realize that somehow you better disconnect the connection when the VHF or radar is used. I also forgot about impedance matching (my god, alzheimers, I taught an engineering lab on impedance matching once). I really don't know how a radar antenna works on small boats. If it is just a rotating dish, it oughta work with the right transducer. The kind with a dome has a printed-circuit board with an array of little antenna elements with fixed phase relationship that produces the beam and receives the echoes. The open ones are slotted wave guides AFIK. I don't see how either would help a cell phone. If they were the right freq, it would work, at least the antenna part. Still have to deal with impedence issues. The slotted wavguide type, are called "Alford" antenna's and they basically act like an array of verticle dipoles. Except they are horizontally polarized. The PCB looking ones, are microstrip patch arrays. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/n1Ghd90bcYOAWPYRAl2zAJ4qlPPEVjtuT9JC8Vvu49wI6E/ycgCfV7J4 F2dRPD5SOoPUGOU0TpBs5fY= =vosS -----END PGP SIGNATURE----- -- Jim Richardson http://www.eskimo.com/~warlock Think for yourselves and allow others the privilege to do the same. - Voltare |
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Come on, Bruce, lighten up. Of course it's a really dumb idea -- many
of Parallax's ideas are dumb and he says so. Occasionally, though, he gets me thinking along unconventional lines, so I go along with the gag on some of his dumbest ones.... Jim Woodward www.mvFintry.com Bruce in Alaska wrote in message ... In article , (Parallax) wrote: For ppl who really want to stay connected while afloat ( I dunno why but they do). Useless Idea #3734 snipped for being "to Stupid to Republish" I never said I had good ideas. However, I realize that somehow you better disconnect the connection when the VHF or radar is used. I also forgot about impedance matching (my god, alzheimers, I taught an engineering lab on impedance matching once). I really don't know how a radar antenna works on small boats. If it is just a rotating dish, it oughta work with the right transducer. OK, an even worse idea.......Use your radar (I dont have one) as a high gain antenna to point toward a cell tower. It ought to work for 900 Mhz. Some electronics could figger out the direction to the best tower. would be nice if folks who don't have a clue would just say they 'Don't have a clue" From Jim Woodward 3) The radar antenna idea actually has some technical merit, and this "technical merit" would be????? Cellphone 800Mhz xBand radar 10Ghz Bzzzt, Try again....... Well not that the "Moorons" have finished lets hope Sanity wins out..... Bruce in alaska |
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"Meindert Sprang" wrote in message ...
"Parallax" wrote in message om... I really don't know how a radar antenna works on small boats. If it is just a rotating dish, it oughta work with the right transducer. Most, if not all, radar antenna's on boats are slotted waveguides. That is a piece of rectangular tube with slots in it. Such a waveguide and slots resonate on 10GHz and will not transport and transmit cellphone signals at 900MHz (aka 0.9GHz). Apart from that, the cellphone system works with datapackets in very tight time-slots. The system compensates for the distance between the tower and the phone (TA: Timing Advance) with a TA value between 0 and 63, for every 550 meters the phone is further away from the tower. This imposes a hard limit on the maximum distance of 550 x 63 = 34.6km or 18.7 miles. So no matter how high your antenna is and how much power you have available, 18,7 miles is the limit. Meindert Meindart: Thanks for the useful info, I agree, the waveguide antenna wouldnt work. Boat radar doesnt use a parabolic antenna with the waveguide horn at the focal point? Why not? |
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"Parallax" wrote in message
om... Thanks for the useful info, I agree, the waveguide antenna wouldnt work. Boat radar doesnt use a parabolic antenna with the waveguide horn at the focal point? Why not? Because a slotted waveguide is cheaper and smaller than a parabolic antenna with a precisely manufactured curvature and a horn. Meindert |
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On Tue, 28 Oct 2003 09:02:16 -0500, "Jeff Morris"
jeffmo@NoSpam-sv-lokiDOTcom wrote (with possible editing): Why don't you just get a cell phone antenna and if needed, an amplifier? With a 4 foot antenna on the stern rail we had contact with ATT for the entire East Coast. The only problem area was Maine, where the coves can be blocked by hills. BTW, one of the proposals for "next generation" cell technology was by a company that specializes in small supercomputers for Defense Dept. radar and sonar systems. The same technology that can "aim" radar can be used to aim cell bandwidth to the customer that needs it at the moment. ....snip Actually, what might make more sense are the new satellite cell phones. I believe they go for around $600, but the per-minute charge is down to around $0.35 and they're good just about anywhere. -- Larry Email to rapp at lmr dot com |
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"Bruce in Alaska" wrote in message
... In article , (Parallax) wrote: Boat radar doesnt use a parabolic antenna with the waveguide horn at the focal point? Why not? Because Marine Radar Antenna's are designed to provide a very narrow Horazontal Beamwidth, so as to descriminate small targets, and a very large Vertical Beamwidth, so as to eliminate loss of targets due to Heeling, Rolling, and pitching for the radar platform...... Which can also be achived with a parabolic antenna, with different curvatures in horizontal and vertical direction. See navy ships... So again, it all comes down to cost. Meindert |
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On Wed, 29 Oct 2003 08:53:39 +0100, "Meindert Sprang"
wrote: Apart from that, the cellphone system works with datapackets in very tight time-slots. The system compensates for the distance between the tower and the phone (TA: Timing Advance) with a TA value between 0 and 63, for every 550 meters the phone is further away from the tower. This imposes a hard limit on the maximum distance of 550 x 63 = 34.6km or 18.7 miles. So no matter how high your antenna is and how much power you have available, 18,7 miles is the limit. This is true for GSM, but not for AMPS and IS-95 CDMA widely used in North America. I have no idea about distance limits for D-AMPS which is TDMA, but it will fall back to AMPS anayway. In Sweden we have some extended range GSM sites allowing up to 70km distance, but they don't cover the majority of the coastline. This can be a problem sometimes, that's why i have an old NMT450 cell phone installed as well. With an antenna 18 m up, and 15W TX at 450 MHz, the range is impressive, to say the least. /Marcus -- Marcus AAkesson Gothenburg Callsigns: SM6XFN & SB4779 Sweden Keep the world clean - no HTML in news or mail ! |
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Parallax,
As Meindert alluded to, a small rotating focused array antenna in an analog radar set is cheaper to make than a focused parabolic when the gain of the parabolic is not needed. Really large stationary arrays are used on radar that is computer focused, such as the USN Aegis missile cruisers. They are 1 million watts on each side I think. Each element in the array has it's own driver. Far too expensive for most pleasure craft. Also the frequency of radar is to far away from the cell frequencies for it's antenna to be effective. Regards, Ron |
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Parallax,
As Meindert alluded to, a small rotating focused array antenna in an analog radar set is cheaper to make than a focused parabolic when the gain of the parabolic is not needed. Really large stationary arrays are used on radar that is computer focused, such as the USN Aegis missile cruisers. They are 1 million watts on each side I think. Each element in the array has it's own driver. Far too expensive for most pleasure craft. Also the frequency of radar is to far away from the cell frequencies for it's antenna to be effective. Regards, Ron |
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