Here is a nice antenna test. Seems they are getting about 14 nm from their radios with an 8 foot antenna. I went with the Shakespeare 5225 XP after reading many reviews. I don't expect nearly that range except to the Coast Guard since mine is mounted at water line just about.
http://www.llelectronics.com/docs/aw...HFAntennas.pdf
DSC travels WAAAY further than voice. Below is a test run with a Nautilus Lifeline VHF which is made for scuba divers, since it can be submersed to 300 ft.
My personal unit.
Hi, Mike Lever here, President of Nautilus Lifeline
here is a comprehensive range test for all who are interested.
safe diving!!
June 29th 2011
Lifeline position report test
Radio : WestMarine VHF580 DSC Marine radio
Radio Tx Info
modulation +- 5 khz deviation
Frequency range : 156 to 158 Mhz
Frequency stabilty +- ppm@ -20 to +50 Celsius
Radio Receiver info
Frequency: range 156 to 163 Mhz
Sensitivity: 0.25uV for 12 dB SINAD
Circuit : Duel Conversion super heterodyne PLL (Crystal for DSC)
Squelch Sensitivity: 0.2 uV threshold
Spurious response: 75 dB
Adjacent Channel Selectivity 78dB @ +- 25KHz
IF Feq: 1at 41.925 Mhz 2nd 455 kHz
If Feq DSC : 1st 21.7 KHz 2nd 455 kHz
Atenna : Galaxy Antenna 5108
Shakespeare Galaxy Eliminator Series found on page 194 of the western marine catalog
SHA-5018-FLT , 17.5 feet long gain 9db
mounted to the mast using the standard Shakespeare mounting kit
found on page 201 western marine part Number : SHA 410
The Antenna is mounted on the Stbd side of the aluminum mast about 2 feet off set from the mast with the antenna whip clear above the top portion of the mast
DSC position report tests
Unit # 024 and 025
Version info
HW:0:01 SW:0.37
software 0.3.14
region : 4
Single position report only
LL was tested by Tim Courtier
tester held radio at all times during testing while lying on dive deck of the skiff holding the LL over on on the water , Line of sight held between LL and swell at all times
WX
Vis:2nm
light rain
2'chop SE
SWELL LOC : 56 45.389 N
132 35.523 W
Line lines tested at different heights above the water once a fail RX was reported for the position report by the swell
LL tested -0.5 - 4 inches from water
Time16:56
Dist 1.8 nm
56.46.420N
132 38.437 W
DSC OK TX
VOICE OK TX
Time 1700
Dist 2.6 nm
56.46.751N
132 38.672 W
DSC OK TX
VOICE OK TX
Time: 1704
Dist 3.5 miles
56.47.141N
132 41.078 W
DSC OK TX
VOICE OK TX
Time: 1708
Dist 4.3 miles
56.47.547N
132 42.452 W
DSC OK TX
VOICE OK TX
LL Tested at 12 inches above water after a single fail while 4 inches from water
Time: 1709
Dist 5.3 miles
56.48.046N
132 43.886 W
DSC OK TX
VOICE Broken but readable
Time: 1712
Dist ? miles
56.48.000N
132 43.000 W
DSC Rx ok on swell - tho eroneous data ?? ...
location is not fully formed
Time 1719
Dist 6.1 miles
56.48.555N
132 45.170 W
DSC OK TX
VOICE very broken up
Time 1722
Dist aprox 7 miles
56.48.576N
132 45.244 W
DSC was transmitted from at lest 7nm from the swell
tho the GPS reading only shows a movement of 200 yards from the last position
thinking this is from the LL losing Gps while bouncing around my seat in the skiff , then me pressing TX before it relocates ..
i also found this to happen during some testing earlier this day, LL was tested on the nautilus , i closed it ,
and left with the skiff , 5 min later i popped it open and pressed send without waiting for the sat lock . it worked from 2nm from the swell but showed the swells location as the pos report
Time 1727
Dist 7nm miles
56.48.876N
132 46.590 W
DSC OK TX
-------------
LL held 18 inches above water or so . i measured from my finger tips touching the water to my elbow and used that as the height a diver would be holding it up and out of the water
Time 1730
Dist 7.8 miles
56.49.073N
132 48.136 W
DSC OK TX
Time 1734
Dist 8.6 miles
56.49.202N
132 49.785 W
DSC OK TX
Time 1740
Dist 9.5 miles
56.49.313N
132 51.375 W
DSC OK TX
Time 1734
Dist 11.8 miles
56.49.582N
132 55.428 W
DSC OK TX
11.8 NM tested both radios , distance was confirmed by a navigation buoy and nautical chart
radios tested about 6 times at this location all DSC position reports received by the Nautilus when the LL was held Apox 22-23 inches from water