Some clarifications may be necessary here. For one thing, there are satellites and then there are satellites. Not all satellites are equal, not by a long shot.
Originally, there were communications satellites. These were normally all geostationary. That means that they were at an orbital altitude of about 22,000 miles and they appear to be hovering over the Equator. These work fine if you have an Earth station and you want to point it at one spot in the sky.
Then we got non-geostationary satellites. GPS (Navstar) satellites are good examples. They fly an inclined polar orbit at about 11,000 miles, so they appear to be moving across the sky. There are dozens of them, so it seems like a complete mesh of satellites in the sky from virtually anyplace on Earth.
At lower orbits, you have the LEO's (Low Earth Orbit satellite). They also appear to be coming and going overhead. Think Globalstar and Iridium satellites.
Different types of satellite use different frequencies, and that choice is governed by the different atmospheric layers and which layers reflect which frequencies. So, a Globalstar or Iridium satellite tends to want to receive an uplink frequency of about 1.62 GHz. In contrast, the international SAR satellites want to receive 406 MHz for an emergency signal.
That 1.62 GHz uplink is an interesting choice of frequency. It isn't too far from the GPS downlink frequency (1.57 GHz). The difference, of course, is that with a Globalstar or Iridium, you have the transmitter power on Earth pointed upward, and in GPS you have the (much higher) transmitter power in space pointed downward. But then, GPS "birds" are much higher, so there is much more distance to transmit.
With Globalstar and Iridium, they work by "bouncing" all uplink signals back to some Earth station on the Earth's surface. That works fine as long as they are close to land where the Earth stations are located. But that does not work when they are out over the middle of the ocean where there are no Earth stations. That is something to consider if you are a mariner at sea, but that is not an issue for a backpacker. Some of these LEO satellite networks are more complete than others, and that dictates some of the reliability of a single message getting through. In contrast, the international SAR satellites are up higher, so they tend to "see" emergency beacons more reliably.
The U.S. military specifically chose 1.57 GHz for the primary GPS downlink frequency because it works in all weather. You would not want a frequency that would fail during some foul-weather military mission. So, the nearby 1.62 GHz frequency should be almost the same. I don't think that you would want to try to transmit over your Iridium phone link when you are trying to get an accurate GPS position fix at the same time. High powered transmitters and low powered receivers don't mix, at least at the same frequency and the same instant of time.
That 1.57 or 1.62 can get mangled by overhead foliage, and that is especially true if the foliage is fresh and green (holding lots of water) or else if the foliage is dripping wet from rain or snow. If you think this is a factor, then move out into the open if possible.