Boatist
Rear Admiral
- Joined
- Apr 22, 2002
- Messages
- 4,552
Re: VHF Radio stationery or handheld?
DSC (Digital Selective Calling) is a way to send a Digital MayDay Call to the Coast Guard and every boat in range in 1/3 of a second.
VHF radios sold in the USA must have DSC CLASS D or higher starting March 25 2011.
VHF RADIOS THAT HAVE DSC SC101 AFTER MARCH 25 2011 MAY NOT BE SOLD, IMPORTED, OR INSTALLED IN THE USA AFTER THAT DATE.
SO BE CAREFUL BUYING A VHF RIGHT NOW AS MANY DEALERS ARE TRYING TO GET RID OF THEIR SC101 RADIOS BEFORE MARCH 25 2011.
DSC has many features but the most important is the one above.
Coast Guards task called RESCUE 21 is to be able to receive a 1 Watt VHF radio signal out 30 miles along the entire coast of the USA.
DSC when hooked up to a GPS and with you MMSI number will be able to Send a Digital MayDay to the Coast Guard and every boat in range in about 1/3 of a second.
This DSC message will include your GPS position and your Identification Number.
Coast Guard will call you back on channel 16 and your radio will automatically switch to channel 16.
Coast Guard likes to call it taking the SEARCH out of Search and Rescue.
So Coast guard now knows where you are and what Boat they are looking for.
Class D DSC radios have a separate receiver for channel 70 for DSC.
Class SC101 radios scan channel 70 along with all the other channel you are scanning so very unlikely to receive a DSC call.
VHF range with an antenna top of 11 feet above the Water is about 4.71 Miles plus the range of the other station.
So Boat to Boat range is just under 10 miles for many boats.
Out here in California in many areas Boat to Coast Guard range is often over 80 miles because Coast Guards antennas are on top of 3000 foot high mountains.
To determine range in miles take the square root of the antenna height above water times 1.42. Then do the same for the other station and add both together for the total range.
DSC (Digital Selective Calling) is a way to send a Digital MayDay Call to the Coast Guard and every boat in range in 1/3 of a second.
VHF radios sold in the USA must have DSC CLASS D or higher starting March 25 2011.
VHF RADIOS THAT HAVE DSC SC101 AFTER MARCH 25 2011 MAY NOT BE SOLD, IMPORTED, OR INSTALLED IN THE USA AFTER THAT DATE.
SO BE CAREFUL BUYING A VHF RIGHT NOW AS MANY DEALERS ARE TRYING TO GET RID OF THEIR SC101 RADIOS BEFORE MARCH 25 2011.
DSC has many features but the most important is the one above.
Coast Guards task called RESCUE 21 is to be able to receive a 1 Watt VHF radio signal out 30 miles along the entire coast of the USA.
DSC when hooked up to a GPS and with you MMSI number will be able to Send a Digital MayDay to the Coast Guard and every boat in range in about 1/3 of a second.
This DSC message will include your GPS position and your Identification Number.
Coast Guard will call you back on channel 16 and your radio will automatically switch to channel 16.
Coast Guard likes to call it taking the SEARCH out of Search and Rescue.
So Coast guard now knows where you are and what Boat they are looking for.
Class D DSC radios have a separate receiver for channel 70 for DSC.
Class SC101 radios scan channel 70 along with all the other channel you are scanning so very unlikely to receive a DSC call.
VHF range with an antenna top of 11 feet above the Water is about 4.71 Miles plus the range of the other station.
So Boat to Boat range is just under 10 miles for many boats.
Out here in California in many areas Boat to Coast Guard range is often over 80 miles because Coast Guards antennas are on top of 3000 foot high mountains.
To determine range in miles take the square root of the antenna height above water times 1.42. Then do the same for the other station and add both together for the total range.