This roundup of shows and events includes news from the NMEA International Marine Electronics Conference & Expo and the American Boat and Yacht Council.
Attendees at the 2011 NMEA International Marine Electronics Conference & Expo will have an opportunity to talk with a representative of a company whose proposal could have a significant impact on the Global Navigation Satellite System, which includes GPS.
The annual conference of the National Marine Electronics Association will be held Sept. 28-Oct. 1 at the Sanibel Harbour Marriott Resort & Spa in Fort Myers, Fla.
Several months ago, LightSquared Subsidiary applied to the Federal Communications Commission for permission to allow a new 4G Long-Term Evolution wireless broadband service to operate in the radio spectrum immediately adjacent to GNSS services, according to Bob Markle, president of the Radio Technical Commission for Maritime Services.
“The nature of radio transmission is such that it is not possible to contain all of the energy to the intended frequency band,” Markle said in a statement. “There are always out-of-band emissions on neighboring frequencies. There are regulatory limits on the strength of these out-of-band transmissions, and receivers on neighboring frequencies have to be designed to account for them. GNSS satellite signals are extremely weak at the Earth's surface and would be completely drowned out by LightSquared's powerful base station transmissions, perhaps a billion times more powerful than the GNSS signals in the immediate vicinity of the base station.”
When FCC-ordered tests confirmed that significant interference could occur from the company's proposal, it was determined that LightSquared would not operate in frequencies closest to GNSS, but the company indicated that this was “not a permanent solution,” according to Markle.
Geoff Stearn, of LightSquared, will give a presentation at 9 a.m. on Sept. 28 at the opening of the GMDSS Task Force meeting, followed by a brief question- and-answer period.
“This issue is very important to us and our industry because of its possible effects on the GPS system,” NMEA president and executive director David Hayden said in a statement. “Although Geoff will be pressed for time, he will be available after his presentation at the GMDSS session for some short group discussions. We urge members to attend.”
* * *
The American Boat and Yacht Council is hosting two webinars this fall.
Protecting the core, care and feeding of your composite laminate core material is set for 1 p.m. (EDT) Sept. 21.
Cored laminates can provide strong lightweight structures, but maintaining the integrity of the core is critical to the strength of these laminates. In the webinar, ABYC will take a look at some of the basic engineering principles that show why lightweight cores are advantageous in boat construction and some common problems encountered during manufacturing.
On Nov. 9, at 1 p.m. (EST), ABYC will host a webinar on propeller selection and sizing.
Anyone who needs detailed practical information about selecting and sizing propellers and understanding their operation is urged to attend. The webinar begins with a detailed review of basic prop-sizing equations, understanding and calculating slip; geometry refinements; geometry tweaks and propeller function and induced drag.
Next, ABYC will explain how to calculate and specify a propeller for a single-screw displacement boat. Lastly, the webinar will review the propeller selection for a twin-screw planing boat; this will include estimating speed, planing-hull wake factor and cup.