For what it's worth, tunneling and compression services designed for generic internet
or 3G networks are not necessarily optimized for satphone (or SSB
radio) email service
With Satphone and SSB
, the latencies are very high, and the data rates are fairly slow, so the normal TCP/IP handshaking can really slow down the data throughput. Also, it is fairly common to drop the connection in the middle of a satphone or SSB data transfer, and typical protocols will discard the entire partially-sent message. With XGate (and no doubt other) satphone-optimized services, partially-transferred messages are saved, and at the next connection the transfer resumes where it left off. This is a hugely valuable feature.
I am aware that the "resume interrupted download" feature is available for generic internet service
, but not all transfer programs offer it. XGate provides a well-optimized service that goes far beyond simple compression.
I keep mentioning XGate because I have been using it for a number of years, and have been quite satisfied. There may be even better options out there...