SPOT Assist

[MasterBaiter]

I liked the idea of the non-emergency distress. With a PLB, if my understanding is correct it is an all or nothing emergency. All of the troops would be dispatched for what might be a simple tow.

Are there any other options?

[Rainmaker]

I looked at this one also. It looks kind of cool if you want someone to watch you travel but it does not seem to be a good emergency tool. An EPIRB is the way to go for emergency situations.

For Non-Emergency situations I picked up a globalstar sat phone. The phones are available used via your favorite auction site. The service is around $30 a month for unlimited (at least it was when I activated mine) due to the current poor service they have. The service is bad, but I normally can turn the phone on let it sit until it gets connected (sometimes 15-20 minutes) and get a call through. Long conversations drop but short ones are not a problem. Globastar is launching new sats and service should improve over the next 18 months.

With that, I have no issue reaching the Coast Guard or Boat US when I am offshore via VHF. I have raised Boat US on the VHF from the Bahama Banks (60 miles off Stuart FL) for a radio check several times. If I need a tow much further than that, I will reach out to Boat US from West End in the Bahamas.

Not sure what kind of trips you are taking but you should look into the combination sat phone/EPIRB if needed.

Tucker, with the PLB you are right - it is all or nothing and if you activate they send the world looking. Off north Florida and Georgia I have a problem reaching anyone onshore from 40 - 50 miles off with my 25W VHF and an 8 ft antenna. Maybe it's the radio - A fairly expensive ICON. I have to get a relay by someone closer to shore. Wonder what the range of a standard 25W VHF signal should be. I thought it was all line of site - the higher off the water you transmit, the father your signal will reach beyond the curve of the earth. Seems I remember a formula that said for very foot off the water your line of site increased by "x" amount - whatever "x" is. My brain fails me at times...

[BigLew]

An answer to your range problem is on the Orion(?) emergency flare packaging. They produce a "range of visibility chart there to illustrate how the curvature of the earth's surface effects the range of visibility of the different flares they offer. Using the "line of sight" guide of VHF transmission range you can easily interpolate what your VHF range likely is, assuming optimal equipment condition.

Good luck.

PS. They might reproduce the chart or one like it in the West Marine catalog. Come to think of it there might be a VFH range chart there for radio range purposes. Take a look and I will do the same, if I remember to do so. If I get an answer, I'll let you know.

[eggsuckindog]

Down here the guys have them seem to like it - it was and is not supposed to replace an EPIRB - if your running that far offshore an EPIRB should be onboard

Google works wonders:

http://www.naval.com/sight/index.htm

[Fr. Frank]

...I thought it was all line of site - the higher off the water you transmit, the father your signal will reach beyond the curve of the earth. Seems I remember a formula that said for very foot off the water your line of site increased by "x" amount - whatever "x" is. My brain fails me at times...

From 6' above the surface of the water, the horizon is 12 miles away, it says here in my 48th edition of Chapman's Piloting. That's 2 miles per foot. So since line of sight = maximum range, then from an antenna 8' MSL (above mean sea level) to another antenna that is also 8' MSL maximum range 32 miles. That is, of course, degraded by bobbing up and down on the waves. Therefore, according to Chapman's, effective range is generally no more than 70% of maximum.

But wait...Digital VHF radio's are supposed to have 15% greater effective range than analog, (whatever that means). That would make the effective range for a digital VHF 80.5% of maximum range.

Okay, now my brain fails and my head hurts.

[MasterBaiter]

naval.com is not even close to Chapman's calculations.
6 ft antenna on either end produced a 6 mile range according to navel.com.

Am I doing something wrong???

[Fr. Frank]

naval.com is not even close to Chapman's calculations.
6 ft antenna on either end produced a 6 mile range according to navel.com.

Am I doing something wrong???

This made me think. SO I went to "How Stuff Works" to find the following formula:
SquareRoot(height above surface / 0.5736) = distance to horizon.

That works out to about 1 mile for every 8 inches in height. So a 6' antenna (72 inches) has a line of sight of 9 miles.

I wonder if the current Chapman's still has the old guideline? My copy is from the late 1970's.

[BigLew]

Be sure to add in the length of the antenna PLUS the distance above the water to it's mount. In other words, how far above the water is the highest point on the antenna.