I own a couple of Iridium sat phones and always have one with a current active SIM card.
First off, YES you must have a clear line of site to the sky and it has to be a lot of visible sky, not just some little patch. Despite the movies and TV shows, they DO NOT work from the bottom of some mine shaft or underground bunker or inside of a tent or inside of a building. That means they don't work inside of an RV either unless you have a remote outsde antenna installed which has clear unobstructed access to the sky. It also means that even if you're outside, you are not going to make a connection if you're sitting under the RV awning or a lot of shade trees.
So, if you're camped someplace, it's relatively easy to walk someplace where you have a lot of sky access and make your call. Receiving a call is usually a pain due to the lack of consistent sky access. You can receive and send text messages so if a person can't connect to your sat phone for a call, they can leave you a text message. Then, if you are diligent about finding a good sky place and regurally make connection with the sat phone, you'll see their text message and can call them.
DON'T except to go to sleep with the sat phone on in the RV and have it ring during the night if Grandma has a problem if you don't have an external antenna or the external antenna is under the trees.
In the US there are two main sat phone providers for hand held units. They are Iridium which uses 64 or 69 satellites covering the world. Then other is Globalstar which has only a couple of satellites up over the equater. This means the further you go north or south the more blockage they have to their signal. Globalstar per minute cost is cheaper than Iridium because their coverage or connection is not equal at all to Iridium. If you feel that you need a sat phone, then you need one with the most reliable connections.
After buying or renting a phone, you'll find a wide variety of Sim card options. These range from what I buy which is a 500 minute plan with the minutes good for three years any place in the world for $700+. I buy one of these each year which usually means I have 1,000+ minutes on the phone. You will be surprised how many minutes you use when there's an emergency or you have a broke down rig and you're trying to find parts.
From there the SIM packages decrease in cost and usability. By that I mean where you'll be given sat phone access and how long the minutes will last. They can limit access to just Alaska, or to the US and Canada but not Mexico. Life of the minutes can last from three years down to 30 days.
You can rent the phones off of the internet and buy minutes from Amazon. To understand the minute packages you should probably call and talk to the seller to fully understand what you're buying. Also talk to them about the various phones. The slightly older Iridium 9500 and 9505 phones can easily be hooked up to an Iridium remote antenna with a 10' cable and a magnetic base. The trick is to find a metal surface on an RV to use the magnetic base on. I've never tried to use a remote antenna with the newer phones.
I find it a lot easier to just set a time like 8:00PM to check in each night. With a sat phone you only pay for the actual seconds used, they don't round up to the next whole minute like cell phones used to. When you turn on the phone and it successfully registers with the satellite network, it will tell you how many minutes you have left.
Sat phones do not work with 800, 866 and other toll free phone numbers. This is important if you try to make plane reservations - find a non-800# before you need it.
Bill
