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[Question] JS8Call CB SSB Bandwidth? (sh.itjust.works)

submitted 1 month ago* (last edited 1 month ago) by einfach_orangensaft@sh.itjust.works to c/amateur_radio@lemmy.radio

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I am trying to get into digital modes on CB radio (channel 25) and there is a thing i trying to understand.

I did read that a SSB channel on CB has a bandwidth of 1.5khz, but JS8Call only has a bandwidth of 50hz.

I also read that SSB signals "dont fight each other" meaning if 2 people talk i can hear both. Does this mean it should be possible to have 30 simultaneous JS8Call transmissions on a single SSB CB channel?

Do people have to transmit after each other or can they transmit at the same time while being spaced out within the the same channel?

I am new to SSB and have only done FM where the transmission always takes up the same bandwidth no matter how thing of a audio spectrum slice i put in so i try to wrap my head around the whole thing right now but i am a bit confused.

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[–] CrackedLinuxISO@lemmy.dbzer0.com 3 points 1 month ago* (last edited 1 month ago)

Does this mean it should be possible to have 30 simultaneous JS8Call transmissions on a single SSB CB channel?

Yes. If you play around with JS8Call, you'll notice that the UI picks a frequency offset from the SSB band and parks itself there. If you move the offset frequency to be near other traffic, the messages from nearby offsets will auto-populate in the yellow text box.

Do people have to transmit after each other or can they transmit at the same time while being spaced out within the the same channel?

Data frames are synchronized to 15 second time windows (I think). You can transmit during the same window as anyone else, as long as you're not both on the same frequency offset.