(repost due to typos)

On Sunday, March 20, 2016 at 8:32:33 AM UTC-7, David Kinsell wrote:
Both SPOT and InReach use the Iridium sat phone network, but differences
in antennas and the unit's electronics may affect their relative
performance.

No that is completely wrong. Folks have already pointed out they use different networks and that affects reliability. Why not check before posting plain wrong "corrections" to other people's posts?

SPOT is owned by Globalstar, a direct competitor of Iridium.

SPOT uses the L-band simplex data link on the Globalstar satellite constellation. SPOT was developed by Globalstar, in-part to make use of their systems capacity while their S-Band voice data capability was failing on their satellites. SPOT was really just a shrink/consumer repackaging of asset tracking/logistics systems that Globalstar already had deployed. The L-Band network used by SPOT is not the Globalstar S-Band "sat phone network", it happens to share the same satellites that is all.

InReach uses Iridium's constellation. Clearly developed as a response to SPOT. The first InReach product actually used Globalstar's network but they quickly abandoned that (I suspect because they woke up that they were competing with their supplier in a battle they could never win, and Iridium is just technically superior). Iridium offers a superior *duplex* data link capability. Which is why InReach can do two way messaging and SPOT cannot. Iridium is inherently more reliable than the simplex (transmit blind and hope) messaging on Globalstar/SPOT.



On Thu, 10 Mar 2016 09:34:21 -0800, JS wrote:

Alternatively you can connect InReach to a cell phone by bluetooth, and
use the phone's texting features.
As Dale points out, you can buy in cheap - if you don't use tracking.
There's a very usable InReach plan that includes tracking for $25 a
month.
SPOT uses a less reliable satellite network than InReach.
APRS works well too. 3-minute intervals for Lat/Lon, Alt, Heading and
Speed.
Like a GPS logger, if not mounted properly any tracker will be
unreliable.
Jim


On Thursday, March 10, 2016 at 8:50:30 AM UTC-8,
wrote:
The down side is that the text format is a virtual keyboard where you
have to tediously select each letter from packets of three much as in
an old telephone keypad.