Cellular only transmission rates and data length limits

Application Dev
1

Hi,
I have a few questions regarding cellular transmission.

  1. Cellular w Iridium fallback - If I choose to go ahead with this setting but don’t have Satellite Spotter Data available, will it still work?

  2. I noticed there is also a Cellular only option, however, upon going through the codebase, we found a comment above the “spotter_tx_data” function that mentions

  • Currently, there are 2 notable limitations on this function.
  • First, only network type BM_NETWORK_TYPE_CELLULAR_IRI_FALLBACK shows up in the Sofar Ocean API.
  • Second, the data_len has a realistic max of 311 bytes because
  • Iridium messages are limited to 340 bytes, and Spotter adds a 29-byte header

I’d like to know if this is still the case or if it has been fixed and we can see data sent with network type BM_NETWORK_TYPE_CELLULAR on the Sofar Ocean API (since it was mentioned as a future effort in this thread : Spotter_tx_data possible bug - #4 by zachary)

  1. I would like to get more details regarding the exact data_len and transmission rates allowed if one chooses to go over cellular only (with no iridium fallback). The documentation online mentions that cellular provides capability to send entire strings of data as is, but i’d like to know the exact details so that I can code my implementation accordingly.
2

Great questions Gautam.

I don’t know the answer to (1), so someone else will have to answer that. Maybe @timjoh knows?

Regarding (2) — yes, that is all still the case. The cellular-only queue is not fully supported yet. So right now those answers to (3) still apply: max of 311 payload bytes per message. Transmission rate varies widely by deployment conditions and have to be figured out experimentally.