From: Andrew Christie [achristie@sarantel.com] Sent: Monday, June 03, 2013 3:43 AM To: magene@mbari.org Subject: RE: New GPS/Iridium antenna application Hi Gene, I have tried to answer your questions below as much as possible. Regarding your comments regarding other peoples websites offering solution close to what you need. Some of these people are using our elements inside their solution, so although we do not have direct experience designing the housings we know the antennas are capable of operating in these types of environment. Regards Andrew ---------- Forwarded message ---------- From: "Gene Massion" Date: 29 May 2013 22:33 Subject: New GPS/Iridium antenna application To: Cc: I have a new application for which I haven’t been able to find the right commercially available antenna and I’d like to see how your products might be used. I’ve read your design support process but I’d like to make sure I’m not wasting your or my time first. Here are a few requirements 1) Support both GPS and Iridium a. I don’t need GPS to be tracking during Iridium communications. >>We have a number of customers who use our SL1200/SL1250 antennas and an SL3100 family antenna in these types of applications. As long as the Iridium is not transmitting during GPS operation the solution will work well. 2) Operate on a short mast on a small profiling buoy for oceanographic research. a. The antenna(s) will be less than 0.5 meters above the ocean surface. b. As a goal, good performance with pitch and roll of about +/- 20 degrees would be great. I understand performance will degrade with greater pitch and roll and it would be nice to understand something about performance vs. pitch/roll angle. >> Actually we can tolerate a bit more pitch and roll while still working. We have done trials with the antenna on its side and navigation still works with only limited degradation. The biggest area of degradation is with the antenna on its side you might not track 1-2 low elevation satellites in the region pointing sideways behind the antenna. 3) The buoy profiles to 500 meters so the antenna(s) need to survive pressures up to 500 dBar. I’ll provide the pressure housing design in accordance with your design support process if we decide to move forward. a. Of course I need to know which antenna(s) you’d suggest, how they might stack and how much of an air gap is required. As a first guess, an ID of 25mm would require a wall thickness of about 4.0 mm for a 150mm long housing. >> We don’t have any experience with designing housings for this type of pressure, but believe there is no reason the antenna will not work if supported per our guidelines. >> We would suggest a 10mm gap between the antennas to minimize interference between then. Normally we would recommend a cable from the top antenna run down the side of the lower antenna, but spaced several mm away from the lower antenna. 4) The buoy is battery powered and we are trying to get a mission duration of several years so energy efficiency is important. I can accommodate 2 antenna feeds, one for GPS and one for Iridium) with 2 separate cable/connectors if that saves power by eliminating switching circuitry. >> I think this is the best way to go as the Iridium link margin will be key to getting best battery life, so no addition loss in the Iridium path is a good way to go. I have seen a few commercially available antennas (e.g., http://www.tridentsensors.com/Products_files/Deep-sea%20Antennas.pdf ) and know of other research groups that have designs that come close to meeting these requirements but none are exactly right for my application. So the first question is are you aware of any commercially available offerings that meet these requirements? If not, does this application seem suitable for your products and should we continue the design process? Gene Massion Monterey Bay Aquarium Research Institute (MBARI) 7700 Sandholdt Road Moss Landing, CA 95039 831 7751922 (tel) 831 7751646 (fax) http://www.mbari.org This email and any attachments contain proprietary information some or all of which may be confidential, legally privileged and/or otherwise legally exempt from disclosure and should therefore be considered private. It is for the intended recipient only. If an addressing or transmission error has misdirected this e-mail, please notify the author by replying to this e-mail. If you are not the intended recipient you must not use, disclose, distribute, copy, print or rely on this e-mail. When addressed to our clients any opinions or advice contained in this Internet e-mail are subject to the terms of conditions expressed in any of Sarantel's terms of business. Incoming communications will be monitored. Sarantel Limited Registered Office: Unit 2, Wendel Point, Wellingborough, NN8 6BA, UK Registered in England: 3960217 VAT No.: GB 860 2077 43 This email and any attachments contain proprietary information some or all of which may be confidential, legally privileged and/or otherwise legally exempt from disclosure and should therefore be considered private. It is for the intended recipient only. If an addressing or transmission error has misdirected this e-mail, please notify the author by replying to this e-mail. If you are not the intended recipient you must not use, disclose, distribute, copy, print or rely on this e-mail. When addressed to our clients any opinions or advice contained in this Internet e-mail are subject to the terms of conditions expressed in any of Sarantel's terms of business. Incoming communications will be monitored. Sarantel Limited Registered Office: Unit 2, Wendel Point, Wellingborough, NN8 6BA, UK Registered in England: 3960217 VAT No.: GB 860 2077 43 This email and any attachments contain proprietary information some or all of which may be confidential, legally privileged and/or otherwise legally exempt from disclosure and should therefore be considered private. It is for the intended recipient only. If an addressing or transmission error has misdirected this e-mail, please notify the author by replying to this e-mail. If you are not the intended recipient you must not use, disclose, distribute, copy, print or rely on this e-mail. When addressed to our clients any opinions or advice contained in this Internet e-mail are subject to the terms of conditions expressed in any of Sarantel's terms of business. Incoming communications will be monitored. Sarantel Limited Registered Office: Unit 2, Wendel Point, Wellingborough, NN8 6BA, UK Registered in England: 3960217 VAT No.: GB 860 2077 43