Earlier today I received an alert from AMSAT UK on YouTube. They posted a video presentation about the new geostationary amateur satellite QO-100. I would like to open the discussion about the latest narrow bandwidth data modes like JS8, and how they might be used alongside geostationary transponder satellites, like QO-100.
Most have heard, watched or seen me talking about JS8Call at one time or another. It is a narrow bandwidth digital mode we use for weak signal communications. What you probably don’t know about are the new speeds coming to JS8. In version 2 of JS8Call, there will be Normal, Fast and Turbo modes for users. I believe JS8 along with a geostationary transponder satellite, would make a perfect data mode communications team up, for persistant emergency communications nets.
Why JS8? Transponder satellites have very limited bandwidth. Wider voice or data modes, will limit the number of concurrent operators capable of simaltaeneous communications through the transponder. Using a narrow bandwidth mode like JS8, which can be throttled up, or throttled back depending on the type and priority of comms, allows a more efficient use of the transponders limited bandwidth. In fact JS8 could be used for a persistant net, without limiting the birds capacity in any way.
JS8 also gives us some advantages over other modes.
- Positioning JS8 and APRS
- Chat modes
- Group chat
- Very low power requirements
Using a geostationary transpoder would allow a persistant data net to be maintaned. Normally we would do this over HF or VHF as required. Using a geostationary transponder means the net would never have to go down.
Why narrow bandwidth data modes? Voice communications are great for tactical comms eg, vehicle convoys, what you need right here right now, … If you want to manage people, assets, information … doing it by voice, CW, … has no redundancy and is impossible to manage, as the network I/Os increase. Add simaltaeneous streams of data and it become impossible for an individual to decode it all. If you miss something, the informaiton needs to be sent again. These are great fallback modes, but JS8 can decode the entire bandpass of simaltaeneous signals, and store that information locally. Miss something, just scroll back and read it again. Need to forward that to another network, copy, paste, print or share. It’s not a competition, but the benefits of a system approach to managing info and assets on a data net should be clear. This is where network data modes shine.
During winter 2019, i’ll start planning my ground stations for QO-100. One fixed station, one portable station. I’ll need to consider uplink, downlink, rigs or sdr to use, antennas (fixed and portable). Once I have all the gear, it’ll be time to make some tutorials on getting it all setup.
Finally, try to consider i’m just thinking out loud at this point. Actually putting it down so that (at least in my head) it becomes real. Video of the presentation is below.