4 ms·
Yes, Iridium SBD requires transmitting before you can receive. I did not know about Global Data Burst; I think that's what you're referring to. Holy cow it's
by karma_pharmer 3y ago
Yes, Iridium SBD requires transmitting before you can receive.
I did not know about Global Data Burst; I think that's what you're referring to. Holy cow it's expensive though, although I guess it has to be since you're using a lot more bandwidth*footprint. Like $6.00 per message per delivery area expensive. And they're kinda vague on how big a "delivery area" is.
https://apollosat.com/featured/iridium-gdb-pager/ https://apollosat.com/featured/iridium-gdb-pager/
- lxgr 3y agoNo, I’m referring to the Iridium pager, which is just its own service and has been around longer than SBD, I believe. Messages were (are?) free to send on top of a monthly flat subscription rate per pager. GDB seems to be a successor to that, though.
- kotaKat 3y agoGDB is just a branding for their own flavor of what they're selling which is Iridium Burst, which also appear to run on the 9602/9603 SBD modules, so... maybe Iridium Burst is just spicier Iridium SBD? https://www.iridium.com/services/iridium-burst/ https://www.iridium.com/services/iridium-burst/
- lxgr 3y agoSBD is bidirectional unicast (and mandatorily so; as you say, SBD can't transmit to devices before they initiate a mailbox exchange, with the exception of a "message waiting" indicator. Iridium Burst seems to be multicast-capable, and optionally bidirectional or unidirectional, so "spicier SBD" makes sense! But their paging service was definitely unidirectional and unicast. Here's an old talk on decoding the signal, if you're curious: https://media.ccc.de/v/31c3_-_6236_-_en_-_saal_1_-_201412281645_-_iridium_pager_hacking_-_sec_-_schneider https://media.ccc.de/v/31c3_-_6236_-_en_-_saal_1_-_201412281...
- kotaKat 2y agoYep -- actually contributed an NAL Shout Nano so they had additional protocol decoding on top of SBD ;)