Start with the battery, because it is the single most common point of failure. The Iridium 9555 is rated for about 4 hours of talk and 30 hours of standby, and the IsatPhone 2 for up to 8 hours of talk. Those figures assume a healthy cell and mild temperatures. Cold cuts them hard, and a handset that has been hunting for signal in a valley all afternoon drains faster than one on a ridge. A second battery doubles your working time for the weight of a granola bar.

Next is how you refill. Every handset ships with an AC wall charger, and most ship with a DC vehicle charger. What most kits do not include is a way to charge a battery outside the phone. Single bay and four bay desktop chargers let a team keep spares topped up while the handset stays in the field, which is how fleets and response teams run rotations. The Globalstar GAC-1700 goes one step further and charges a loose GPB-1700 while powering the phone at the same time.

Away from any outlet, a USB power bank or a solar pack is the answer. The Deluxe Iridium Solar Kit pairs a 30,000 mAh solar battery pack with 5 V 2.1 A USB output and a T5000 hard case with pluck foam, and it charges any Iridium 9505A, 9555, 9575 or PTT handset over the standard USB cable. For anything bigger, a laptop, a BGAN terminal, a cabin, look at the power stations at Off-Grid Power rather than a phone accessory.

A 12 V DC charger keeps a handset alive on a long drive, but it does nothing for signal. To call from inside the vehicle you also need the antenna section below.

Every handset antenna wants a clear view of the sky, ideally the whole sky. Inside a vehicle the roof blocks most of it. Inside a building or a wheelhouse it blocks all of it. An external antenna moves the receiving element outside, on the roof or the mast, and brings the signal to you down a cable. The handset then works from the driver's seat, the chart table or the site office exactly as it would standing in a field.

The pieces are simple. An antenna, a cable of the right length with the right connector, and an adapter that plugs into your particular handset. The Iridium 9555 uses a TNC female adapter that comes in the box. The Iridium GO uses a short TS9 to TNC adapter cable. IsatPhone 2 uses its own antenna kit. Match the adapter to the handset first and the rest follows.

Cable length has a hard limit. A passive antenna, the ordinary kind, works out to roughly 30 metres of coax before the signal is lost in the cable. Beyond that you need an active antenna, which has an amplifier in the base and runs on preset cable lengths from 27 metres up to 160 metres. Vessels and fixed sites with long runs from the mast to the office use active antennas. Vehicles and cabins almost never need one.

A magnetic mount antenna is the fast option for a vehicle: it sits on the roof, needs a flat steel surface to grip, and comes off when you park. Fixed screw mount and mast antennas are for permanent installs on boats, buildings and fleet vehicles. The 5 metre Iridium magnetic antenna, for example, is rated from minus 40 to plus 70 degrees Celsius and works with the 9505, 9505A, 9555, 9575 and GO.

Most satellite handsets are rated IP65, which means dust tight and protected against water jets, not immersion. The Iridium 9555, the 9575 Extreme and the IsatPhone 2 all carry IP65. The ICOM IC-SAT100 is IP67, rated for a metre of water for 30 minutes. None of them like being dropped on rock, and none of the screens like a pocket full of keys. A leather holster for daily carry and a hard case for transport are the two purchases that keep a handset working for a decade.

Hard cases come in sizes for a handset alone or a full kit with spare batteries, chargers and an antenna. The T5000 and the SE-300 have pluck and pick foam so you cut the cavities yourself. A grab and go emergency kit lives in one of these, charged and labelled, by the door.

A Faraday bag is a different kind of protection. The EscapeZone satellite phone Faraday bag is a signal blocking pouch that the manufacturer states blocks cellular, GPS, Wi-Fi, Bluetooth and RFID. It is for people who need the handset unreachable and untrackable when it is not in use, and for keeping a fob or a phone isolated in transit. It does not protect the phone from water or impact, so it goes inside the hard case, not instead of it.