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Microwave leak detector
Any radar experts?
I was wondering if a Microwave leak detector could be 'doctored' for use as an 'S' band radar detector for use while cruising. They are pretty sensitive but would possible need some type of antenna and also I don't know if they could cover the actual band width used by ships's radar. They would also need to set-up with an alarm. For example, one I looked at for $49.oo Sensitivity to a wide range of frequencies Calibrated at 2.4 gigahertz, which is the operating frequency of microwave ovens Sensitivity down to 0.01mW/cm2 at 2450MHz. Reads up to 9.99mW/cm2 in hundredths of mW/cm2. What do you think? Cheers, Jim |
Microwave leak detector
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Microwave leak detector
wrote in news:fb2cbd4c-164a-4c0f-aee9-2ef93949e881
@d4g2000prg.googlegroups.com: What do you think? Useless. Wrong band! Boat radars are on X-band (or what used to be X- band). They operate on 10GHZ....WAY too far from 2450 Mhz microwave leak detectors. You'll be fine if you don't put your gonads right up against the feedhorn or planar panel and hold it. AVERAGE power of a boat radar is TINY....very narrow pulse width to get fine resolution returns....long rest times to hold down the battery drain current. http://www.furunousa.com/Furuno/Doc/...FODH2N7B/1715% 20Brochure%20b.pdf This 2.2KW PEAK output Furuno uses 38W of power at full display brightness and power output. Of that 38W, most of it is display lighting and magnetron filament heating up the maggie. It's AVERAGE (heating) output power is probably around 2W, tops. Rotating properly, you'd have to put your nose up against the radome for 20 years before your first cataract operation. ANY cop hiding his 24GHZ CONTINUOUS WAVE doppler radar bouncing off the lead glass windscreen of his cruiser is in FAR FAR more danger of RF than you could ever be. ---------------------------------------------------- Now, I used to play with this radar my rich uncle bought me: http://en.wikipedia.org/wiki/AN/SPS-49 If you had any brains, you didn't go anywhere near its antenna while it was on. It cooked seagulls right out of the sky!...(c; |
Microwave leak detector
In article ,
larry wrote: Useless. Wrong band! Boat radars are on X-band (or what used to be X- band). They operate on 10GHZ....WAY too far from 2450 Mhz microwave leak detectors. Well, not quite right, but close. There are a number of S Band Marine Radars in use, and available, worldwide. They are mostly used on ships LARGER than 1200 Tons, and used as Weather Radars, and Long Distance Position Fixing. Larry is correct, in that MOST Consumer and Small Ship Radars, are X Band, and your detector wouldn't see ANY of those. Bruce in alaska -- Bruce in alaska add path after fast to reply |
Microwave leak detector
Bruce in alaska wrote in news:fast-151579.10373820012008
@netnews.worldnet.att.net: They are mostly used on ships LARGER than 1200 Tons, I figured most of these boys and girls were on plastic bubbleboats and didn't have 8MW air search radars aboard....(c; |
Microwave leak detector
In article ,
John Navas wrote: http://www.sea-me.co.uk/ ... BTW: Do these (active reflectors) also work if you have your own radar, ie will they make you visible to other vessels? Or is it only possible to use passive ones (90? reflectors, Luneburg lenses)? Never quite figured that out in spite of my MSEE degree :-) Marc -- remove bye and from mercial to get valid e-mail http://www.heusser.com |
Microwave leak detector
On Mon, 21 Jan 2008 01:06:06 +0100, Marc Heusser
d wrote: In article , John Navas wrote: http://www.sea-me.co.uk/ ... BTW: Do these (active reflectors) also work if you have your own radar, ie will they make you visible to other vessels? Or is it only possible to use passive ones (90? reflectors, Luneburg lenses)? Never quite figured that out in spite of my MSEE degree :-) Marc It appears from the user handbook that the thing is a radar transponder - on receipt of a signal in the appropriate frequency range, it will transmit a brief pulse on that frequency, which will appear as an obvious mark on the radar screen, just like a RACON. It is independent of your own radar - but must be mounted so that it will not be triggered by your radar. -- Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca |
Microwave leak detector - active radar reflectors
In article .com,
Peter Bennett wrote: On Mon, 21 Jan 2008 01:06:06 +0100, Marc Heusser d wrote: In article , John Navas wrote: http://www.sea-me.co.uk/ ... BTW: Do these (active reflectors) also work if you have your own radar, ie will they make you visible to other vessels? Or is it only possible to use passive ones (90? reflectors, Luneburg lenses)? Never quite figured that out in spite of my MSEE degree :-) Marc It appears from the user handbook that the thing is a radar transponder - on receipt of a signal in the appropriate frequency range, it will transmit a brief pulse on that frequency, which will appear as an obvious mark on the radar screen, just like a RACON. Yes, so much is clear. It is independent of your own radar - but must be mounted so that it will not be triggered by your radar. That is most likely impossible. At a few kW of transmitting power (peak), it will trigger when the distance is only a few metres at most. The question is, whether it still appears on other radars. Marc -- remove bye and from mercial to get valid e-mail http://www.heusser.com |
Microwave leak detector - active radar reflectors
On Mon, 21 Jan 2008 08:49:02 +0100, Marc Heusser
d wrote in : In article .com, Peter Bennett wrote: It is independent of your own radar - but must be mounted so that it will not be triggered by your radar. That is most likely impossible. At a few kW of transmitting power (peak), it will trigger when the distance is only a few metres at most. Marine radars have a limited vertical beam width, and the transponder should be mounted above or below that vertical pattern. See the Handbook: If Sea-me is being fitted elsewhere, say on a radar arch, ensure that it is above the superstructure of the vessel and that it is not within the vertical beamwidth of any radar which may also be fitted. Normally this means that the Sea-me antenna unit must be above or below a 30° line from the centre of a radar antenna but you will need to refer to your radar manual to confirm this. .... Radars have many leakage paths and so Sea-me will respond to your own radar’s pulses (typically a pulse is 1 microsecond long and is repeated every 1 millisecond). The LED flash has been extended to 100 milliseconds to make it visible to the human eye and so it will be permanently on when your own radar is transmitting. However Sea-me transmits in response to an incoming pulse and so it will respond to any which arrive in the spaces between the pulses put out by your own radar. Typically the ratio of space to pulse is 1000:1 and so there are 999 microsecond spaces for every 1 microsecond pulse received, plenty of time for others to get in, even when electronic recovery time has been allowed for. This effect does however mean that Sea-me, because the active light is on, will be unable to tell you that you are being struck by another radar. If this is a concern then you are advised to switch your radar into its standby mode when you are not actually using it. You probably do this anyway in order to save power. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
John Navas wrote in
: Marine radars have a limited vertical beam width, and the transponder should be mounted above or below that vertical pattern. See the Handbook: WRONG! Geez, John.... Marine radars have limited HORIZONTAL beamwidth so you can see 3 targets kinda close together as 3 targets, not 1 blob. They have WIDE VERTICAL beamwidth so they are pointing at the horizon EVEN WHEN THE BOAT IS HEELED OVER OR ROLLING! If they had narrow vertical beamwidth, the only time you'd see the target is in flat water or at the marina dock! |
Microwave leak detector - active radar reflectors
On Mon, 21 Jan 2008 16:48:25 +0000, larry wrote in
: John Navas wrote in : Marine radars have a limited vertical beam width, and the transponder should be mounted above or below that vertical pattern. See the Handbook: WRONG! Geez, John.... Marine radars have limited HORIZONTAL beamwidth so you can see 3 targets kinda close together as 3 targets, not 1 blob. They have WIDE VERTICAL beamwidth so they are pointing at the horizon EVEN WHEN THE BOAT IS HEELED OVER OR ROLLING! If they had narrow vertical beamwidth, the only time you'd see the target is in flat water or at the marina dock! Read the Handbook. 30° is actually greater than many units. Garmin GMR 18 HD and GMR 24 HD are 25°. Likewise Furuno and Lowrance, etc. Check the specs if you still don't believe me. Many marine radars are gimbal mounted to address the heeling issue. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
In article ,
larry wrote: John Navas wrote in : Marine radars have a limited vertical beam width, and the transponder should be mounted above or below that vertical pattern. See the Handbook: WRONG! Geez, John.... Marine radars have limited HORIZONTAL beamwidth so you can see 3 targets kinda close together as 3 targets, not 1 blob. They have WIDE VERTICAL beamwidth so they are pointing at the horizon EVEN WHEN THE BOAT IS HEELED OVER OR ROLLING! If they had narrow vertical beamwidth, the only time you'd see the target is in flat water or at the marina dock! "Limited" is such a nondescript word. It really doesn't define what either of you are trying to say. Marine Radar Antennas, typically have a 25 Degree Vertical Beamwidth, Now to some that may be "Limited", (25° as opposed to 360°) but when compared to a Marine Radars Horizontal Beamwidth, (Typically 2° to 6°) it is not "Limited" at all. John's Point, was that the Radar Transponder MUST be mounted Clearly OUTSIDE the Vertical Beamwidth of the Onboard Radar, so as to not be triggered by the operation of the onboard Radar. This is correct. Bruce in alaska -- Bruce in alaska add path after fast to reply |
Microwave leak detector
In article ,
larry wrote: Bruce in alaska wrote in news:fast-151579.10373820012008 @netnews.worldnet.att.net: They are mostly used on ships LARGER than 1200 Tons, I figured most of these boys and girls were on plastic bubbleboats and didn't have 8MW air search radars aboard....(c; Your Squid background is showing Larry, Most Commercial Shipping Vessels larger than 1200 Gross Tons, will have both XBand and SBand Radar fitted, and the SBand Radar, these days is used to detect Weather Fronts, Squalls, Etc. Back in the day, they would be used for Long Distance Position Fixing, as they had better Range than the fitted XBand Radars. GPS and Loran have taken over the Position Fixing Job, in modern Navigating, so SBand, which sees Atmospheric Moisture, much better than XBand, is used for that. Xband has much better Resolution than SBand, so it is used, to keep from running into other moving objects, inside the local path of the vessel. No Ship should be using Radar to keep from running into non-moving Objects, as GPS, Charts, and the Mark One Eyeball, should take care of that, and if not then the Master is sorely lacking in navigation skills. -- Bruce in alaska add path after fast to reply |
Microwave leak detector - active radar reflectors
Bruce in alaska wrote in news:fast-EB795C.10155321012008
@netnews.worldnet.att.net: John's Point, was that the Radar Transponder MUST be mounted Clearly OUTSIDE the Vertical Beamwidth of the Onboard Radar, so as to not be triggered by the operation of the onboard Radar. This is correct Noone is going to run a radar transponder and radar on the same boat. That transponder is going to go berserk re-radiating your own radar. There's all kinds of crazy side lobes on the ****ty PC board antenna on any radome array. The lobes don't have a lot of power, but sure more than enough power to set off a transponder, even if you put the damned antenna in the BILGE! What a crazy idea.... |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 06:19:37 +0000, larry wrote in
: Bruce in alaska wrote in news:fast-EB795C.10155321012008 : John's Point, was that the Radar Transponder MUST be mounted Clearly OUTSIDE the Vertical Beamwidth of the Onboard Radar, so as to not be triggered by the operation of the onboard Radar. This is correct Noone is going to run a radar transponder and radar on the same boat. That transponder is going to go berserk re-radiating your own radar. There's all kinds of crazy side lobes on the ****ty PC board antenna on any radome array. The lobes don't have a lot of power, but sure more than enough power to set off a transponder, even if you put the damned antenna in the BILGE! What a crazy idea.... Not at all. They serve different purposes, and are complementary. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
In article ,
larry wrote: .... Noone is going to run a radar transponder and radar on the same boat. Is it? ... but sure more than enough power to set off a transponder, even if you put the damned antenna in the BILGE! Of course, but so what. I cannot see anything with my radar up to some 15 metres anyway (assuming 50 ns pulse). The key is if it still responds to other radars. What a crazy idea.... Why? The radar expands what I see, and the transponder expands, what others with a radar see. I have seen how unreliable echos from glass fibre reinforced polyester boats are (and how unreliable echos at least smaller passive radar reflectors of the 90° aluminum sheets type give on quiet waters). Small wonder aircraft all have a transponder. Marc -- remove bye and from mercial to get valid e-mail http://www.heusser.com |
Microwave leak detector - active radar reflectors
Marc Heusser d wrote in
: I have seen how unreliable echos from glass fibre reinforced polyester boats are (and how unreliable echos at least smaller passive radar reflectors of the 90ø aluminum sheets type give on quiet waters). If you're going to buy anything to make you a big target on the SHIPS and large yachts....buy an AIS TRANSPONDER, which makes you as big as an aircraft carrier. All ship over 300 gross tons now have full AIS aboard, as do the big yachts, to make them look big. Every boat that leaves the harbor should be AIS equipped, now. Of course, every harbor should have: http://www.aisliverpool.org.uk/ too. It'll come, eventually. |
Microwave leak detector - active radar reflectors
larry wrote in news:Xns9A2D69494A46Bnoonehomecom@
208.49.80.253: All ship over 300 gross tons now have full AIS aboard, as do the big yachts, to make them look big. Name: Grand Esmeralda MMSI: 636012671 [LR] IMO: 8920062 Callsign: A8GX9 Speed/Dir: 14.2 kts / 278° W Status: Underway Dest: Mobile,Alabama ETA: Feb06 06:00 Type: Cargo (70) Size: 225m x 32m x 7.3m Received: 15:17:50 22 Jan 08 GMT Just snapped his picture on the webpage. Long trip to Mobile from Liverpool. He just left. Not only would the mate driving that tanker know you were there....He'd know a lot about you, too, and his computer would make sure he didn't collide with you unless you did something really stupid. We could even call him with his callsign... |
Microwave leak detector - active radar reflectors
larry wrote:
Marc Heusser d wrote in : I have seen how unreliable echos from glass fibre reinforced polyester boats are (and how unreliable echos at least smaller passive radar reflectors of the 90ø aluminum sheets type give on quiet waters). If you're going to buy anything to make you a big target on the SHIPS and large yachts....buy an AIS TRANSPONDER, which makes you as big as an aircraft carrier. All ship over 300 gross tons now have full AIS aboard, as do the big yachts, to make them look big. I'm still waiting to upgrade my AIS receiver for a transponder. At least I can see and identify a threat and call by name on VHF. From 'The Pilot' the magazine of the United Kingdom Maritime Pilots' Association, quoting a working harbour pilot: "With respect to the type of equipment installed, the overwhelming majority of vessels are fitted with the minimum required to comply with carriage regulations! These are small alpha numeric displays which at the absolute basic level have to display at least three targets. I have seen such minimal three line units on ships and for all practical purposes they are totally useless. Other systems cram a list of many targets into the small display (typically 9cm x 12cm) which renders them illegible and again these are totally useless. It is of extreme importance to the Class B user to be aware that there is no statutory requirement for SOLAS vessels to be able to display AIS targets on a screen merely a requirement to provide a simple alphanumeric Minimum Keyboard and Display (MKD). To meet the minimum requirements this display need show no more than three ships at any one time detailing bearing, range and name of ship. Therefore Class B users must understand that their vessel may not be appearing as a 'bright beacon' on the displays of the majority of SOLAS vessels. Although IMO requires all new radars fitted after 1 July 2008 to have good AIS display capabilities, existing radars will not have to be upgraded and so it will be many years before AIS data can be effectively used for navigation on many SOLAS vessels." |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 15:10:52 +0000, larry wrote in
: Marc Heusser d wrote in : I have seen how unreliable echos from glass fibre reinforced polyester boats are (and how unreliable echos at least smaller passive radar reflectors of the 90ø aluminum sheets type give on quiet waters). If you're going to buy anything to make you a big target on the SHIPS and large yachts....buy an AIS TRANSPONDER, which makes you as big as an aircraft carrier. All ship over 300 gross tons now have full AIS aboard, as do the big yachts, to make them look big. True of commercial ships, but *not* of many pleasure craft. Every boat that leaves the harbor should be AIS equipped, now. "Let them eat cake?" And small comfort when one of them collides with you. Until the world comes around to your PoV, a radar transponder is a highly recommended safety device whether you have radar or not. I would still use one even with AIS -- you can never have enough backup -- depending on a single device is just plain foolish. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
BrianH wrote in news:1d379$47960e55$50dbe397$1297
@news.hispeed.ch: I'm still waiting to upgrade my AIS receiver for a transponder. At least I can see and identify a threat and call by name on VHF. What I always find amusing, out at sea, is the reluctance of the yachties to simply TALK to the ships. It's as if that SeaLand containership were full of pirates and they're afraid of being attacked or ****ing off the bored-to-death mate at the helm. I had a first mate on a freighter I was talking to on Ch 13 a hundred miles off Savannah try to trade me for the 35' Endeavour sloop I was driving. We decided we couldn't dock a 400 footer at our little slip at Ashley Marina, though it would have made the marina just thrilled if I stopped by the diesel dock....just fueling the generators! They're really nice guys and WANT you to call 'em and tell them at least where you are and what you are. "Can you flash your searchlight at me?", many have asked me. We got a monster handheld. "Ah, now I see where you are. I can hardly make out your masthead light from here." I was 6 miles away, so I guess that was OK. The searchlight made us a much bigger target. TALK TO THEM, dammit! There's just times when being a sailing hermit is stupid! |
Microwave leak detector - active radar reflectors
larry wrote:
BrianH wrote in news:1d379$47960e55$50dbe397$1297 @news.hispeed.ch: I'm still waiting to upgrade my AIS receiver for a transponder. At least I can see and identify a threat and call by name on VHF. What I always find amusing, out at sea, is the reluctance of the yachties to simply TALK to the ships. It's as if that SeaLand containership were full of pirates and they're afraid of being attacked or ****ing off the bored-to-death mate at the helm. I've been recently following a few MAIB (UK) yacht/ship collision reports and I am mystified why the yacht failed to attempt to use a serviceable VHF radio to warn that they were being run down. The much-publicised loss of the Ouzo off the Isle of Wight in 2006 is a classic example. This is especially so when compared to the banal chat I often hear from many yachts calling their buddies. |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 20:01:06 +0100, BrianH wrote in
: larry wrote: BrianH wrote in news:1d379$47960e55$50dbe397$1297 @news.hispeed.ch: I'm still waiting to upgrade my AIS receiver for a transponder. At least I can see and identify a threat and call by name on VHF. What I always find amusing, out at sea, is the reluctance of the yachties to simply TALK to the ships. It's as if that SeaLand containership were full of pirates and they're afraid of being attacked or ****ing off the bored-to-death mate at the helm. I've been recently following a few MAIB (UK) yacht/ship collision reports and I am mystified why the yacht failed to attempt to use a serviceable VHF radio to warn that they were being run down. The much-publicised loss of the Ouzo off the Isle of Wight in 2006 is a classic example. This is especially so when compared to the banal chat I often hear from many yachts calling their buddies. Many mariners have no idea what channel to use. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
In article ,
larry wrote: If you're going to buy anything to make you a big target on the SHIPS and large yachts....buy an AIS TRANSPONDER, which makes you as big as an aircraft carrier. Don't worry, I have one. But: They're not everywhere. European inland waterways for example do not yet use them - hopefully they will soon. And not all pleasure craft have one. But other than that: AIS is a great system. Marc -- remove bye and from mercial to get valid e-mail http://www.heusser.com |
Microwave leak detector - active radar reflectors
In article ,
Marc Heusser d wrote: Of course, but so what. I cannot see anything with my radar up to some 15 metres anyway (assuming 50 ns pulse). The key is if it still responds to other radars. The other guy can't see you closer than 15 Meters anyway, as his T/R turnaround time isn't that fast either.... and if your worried about things closer than 15 meters, you boat isn't big enough... and your blind...... |
Microwave leak detector - active radar reflectors
In article ,
John Navas wrote: On Tue, 22 Jan 2008 15:10:52 +0000, larry wrote in : Marc Heusser d wrote in : I have seen how unreliable echos from glass fibre reinforced polyester boats are (and how unreliable echos at least smaller passive radar reflectors of the 90ø aluminum sheets type give on quiet waters). If you're going to buy anything to make you a big target on the SHIPS and large yachts....buy an AIS TRANSPONDER, which makes you as big as an aircraft carrier. All ship over 300 gross tons now have full AIS aboard, as do the big yachts, to make them look big. True of commercial ships, but *not* of many pleasure craft. Every boat that leaves the harbor should be AIS equipped, now. "Let them eat cake?" And small comfort when one of them collides with you. Until the world comes around to your PoV, a radar transponder is a highly recommended safety device whether you have radar or not. I would still use one even with AIS -- you can never have enough backup -- depending on a single device is just plain foolish. and which do you think COSTS more, a Radar Transponder or an AIS Transponder???? |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 20:56:25 GMT, You wrote in
: In article , John Navas wrote: On Tue, 22 Jan 2008 15:10:52 +0000, larry wrote in : Marc Heusser d wrote in : I have seen how unreliable echos from glass fibre reinforced polyester boats are (and how unreliable echos at least smaller passive radar reflectors of the 90ø aluminum sheets type give on quiet waters). If you're going to buy anything to make you a big target on the SHIPS and large yachts....buy an AIS TRANSPONDER, which makes you as big as an aircraft carrier. All ship over 300 gross tons now have full AIS aboard, as do the big yachts, to make them look big. True of commercial ships, but *not* of many pleasure craft. Every boat that leaves the harbor should be AIS equipped, now. "Let them eat cake?" And small comfort when one of them collides with you. Until the world comes around to your PoV, a radar transponder is a highly recommended safety device whether you have radar or not. I would still use one even with AIS -- you can never have enough backup -- depending on a single device is just plain foolish. and which do you think COSTS more, a Radar Transponder or an AIS Transponder???? C.A.R.D radar transponder: $535 Class B AIS transponders (just coming on the market) are over $1,000 Class A AIS transponders are $4,000-5,000. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 21:21:58 GMT, John Navas
wrote in : On Tue, 22 Jan 2008 20:56:25 GMT, You wrote in : In article , John Navas wrote: "Let them eat cake?" And small comfort when one of them collides with you. Until the world comes around to your PoV, a radar transponder is a highly recommended safety device whether you have radar or not. I would still use one even with AIS -- you can never have enough backup -- depending on a single device is just plain foolish. and which do you think COSTS more, a Radar Transponder or an AIS Transponder???? C.A.R.D radar transponder: $535 Class B AIS transponders (just coming on the market) are over $1,000 Class A AIS transponders are $4,000-5,000. See "Collision avoidance and detection" on my website at http://sail.navas.us/. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
BrianH wrote in news:a110e$47963cb8$50dbe397$5452
@news.hispeed.ch: I've been recently following a few MAIB (UK) yacht/ship collision reports and I am mystified why the yacht failed to attempt to use a serviceable VHF radio to warn that they were being run down. The much-publicised loss of the Ouzo off the Isle of Wight in 2006 is a classic example. This is especially so when compared to the banal chat I often hear from many yachts calling their buddies. You'd think the ship was from another galaxy the way some yachties are afraid to talk to them. It's crazy. |
Microwave leak detector - active radar reflectors
Marc Heusser d wrote in
: But: They're not everywhere. European inland waterways for example do not yet use them - hopefully they will soon. And not all pleasure craft have one. Europe is way ahead of the USA. Hell, our Coast Guard just got VHF radios with TRANSISTORS in them! We had some Coasties aboard for a volunteer inspection on Lionheart last summer. They were fascinated that The Cap'n was tracking all the ships in the harbor on AIS from our slip on the other side of the peninsula. We just have the receiver, too. The transponders for yachts hasn't "settled" yet, last time I looked. They have no capability for AIS that I know of. I haven't been on their bridges, lately, though. It takes forever for USCG to come around to new technologies. |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 21:21:58 GMT, John Navas
wrote: On Tue, 22 Jan 2008 20:56:25 GMT, You wrote in : and which do you think COSTS more, a Radar Transponder or an AIS Transponder???? C.A.R.D radar transponder: $535 C.A.R.D. is only a radar detector, not a transponder. It will indicate the general direction from which it receives radar signals, but does not respond to them, nor indicate the distance to the radar source. I suspect the display would become useless in the presence of multiple radar sources. Class B AIS transponders (just coming on the market) are over $1,000 Class A AIS transponders are $4,000-5,000. There is also a question of whether a radar or AIS transponder is legal on a pleasure craft in the potential user's country. I don't think that any Class B AIS units are approved for use in the US at present. (I don't think that the AIS units should be called transponders, as the transmit function doesn't depend on receiving any signals.) -- Best regards, John Navas http:/navasgroup.com -- Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca |
Microwave leak detector - active radar reflectors
On Tue, 22 Jan 2008 17:01:53 -0800, Peter Bennett
wrote in .com: On Tue, 22 Jan 2008 21:21:58 GMT, John Navas wrote: On Tue, 22 Jan 2008 20:56:25 GMT, You wrote in : and which do you think COSTS more, a Radar Transponder or an AIS Transponder???? C.A.R.D radar transponder: $535 C.A.R.D. is only a radar detector, not a transponder. It will indicate the general direction from which it receives radar signals, but does not respond to them, nor indicate the distance to the radar source. ... My mistake -- sorry -- thanks for catching that. Instead: Sea-me Active Radar Reflector: about $675 Class B AIS transponders (just coming on the market) are over $1,000 Class A AIS transponders are $4,000-5,000. There is also a question of whether a radar or AIS transponder is legal on a pleasure craft in the potential user's country. I don't think that any Class B AIS units are approved for use in the US at present. Correct. (I don't think that the AIS units should be called transponders, as the transmit function doesn't depend on receiving any signals.) They are both transmitters and transponders, since they can be interrogated. -- Best regards, John Navas http:/navasgroup.com |
Microwave leak detector - active radar reflectors
In article .com,
Peter Bennett wrote: Class B AIS transponders (just coming on the market) are over $1,000 Class A AIS transponders are $4,000-5,000. There is also a question of whether a radar or AIS transponder is legal on a pleasure craft in the potential user's country. I don't think that any Class B AIS units are approved for use in the US at present. (I don't think that the AIS units should be called transponders, as the transmit function doesn't depend on receiving any signals.) That unfortunately cannot be explained by technical reasons - Simrad's AI50 is ready. (http://www.simrad-yachting.com/Produ...-Fishfinding/A I50-Automatic-Identification-System/) Marc -- remove bye and from mercial to get valid e-mail http://www.heusser.com |
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