First: measure the connection you actually have
Run a speed test on the device or modem you will stream through, at the location and time of day you normally stream. cellular upload varies enormously by spot in the room and by hour. Three measurements matter:
- Sustained upload speed, not the burst number — stream drops happen when the rate settles, not at the start.
- Stability over 10+ minutes. A 20 Mbps upload that oscillates between 3 and 15 Mbps is worse for live video than a steady 8.
- Latency and jitter: jittery connections buffer and stall even when average speed is fine.
The bitrate math for cellular
Broadcast at 60–70% of your sustained upload, same headroom rule as any connection:
| Sustained upload | Safe video bitrate | Data used per hour (video+audio ≈ +10%) |
|---|---|---|
| 5 Mbps | ~3000 kbps | ~1.5 GB |
| 10 Mbps | ~5000 kbps | ~2.3 GB |
| 15+ Mbps | 6000 kbps (1080p) or 8000 (high-motion) | ~3–4 GB |
At 480p30 / 1500 kbps, an hour of streaming is roughly 700 MB — the mobile-friendly tier. A full 1080p60 event at 6000 kbps plus 3 hours of VOD uploading later can add up fast; plan data caps accordingly. The bitrate calculator does this arithmetic for you.
Hardware path: phone hotspot vs dedicated modem
- Phone hotspot (USB tethering, not Wi-Fi): USB tethering is more stable than broadcasting a hotspot signal — the PC sees it as a wired NIC, no Wi-Fi interference layer.
- Dedicated hotspot device: runs cooler than a phone (heat throttles cellular radios), doesn’t drain the phone everyone needs, and many support external antennas.
- External antenna / MIMO: if the modem supports it and you stream from one fixed desk, an antenna upgrade is the single biggest mobile-stability fix.
OBS settings for a connection that swings
- Rate control: CBR, keyframe interval 2. Ignore “VBR adapts to bandwidth” advice for live — CBR keeps the stream predictable, which the ingest prefers.
- Start conservative: 480p30 at 1500 kbps or 720p30 at 2500–3000 kbps. You can raise quality on a better day; you can’t un-drop a stream instantly.
- 30 fps caps encoder and viewer cost and tolerates jitter better than 60.
- Enable “Dynamically change bitrate” (Settings → Advanced) only as a last resort — it saves the stream from hard loss but visibly mushes the image. Fixed settings you’ve tested beat dynamic swings you haven’t.
What causes mobile drops besides speed
- Tower congestion: performance degrades at predictable busy hours. Test at your actual stream time.
- Band steering: the modem hopping between bands mid-stream causes brief drops. Locking the band (if the device allows) helps.
- Building materials: a phone by the window with a clear tower view can double usable upload versus in the middle of the room.
- Carrier throttling after a data cap: check whether “premium data” buckets apply to hotspot use.
- Background sync: the same cloud-backup trap as home connections — pause everything else on the streaming machine.
Reread the dropped vs skipped frames guide to confirm drops are network-side before blaming the tower: encoder overload produces similar viewer-visible stutters with an entirely different fix.
The hybrid setup most mobile streamers land on
- Primary: wired Ethernet at home base.
- Fallback: dedicated hotspot, USB-tethered, with the bitrate ladder in OBS profiles.
- A copy of both OBS profile presets (Settings → Profiles) named “Home 6000” and “LTE 2500” so switching is one menu action.
Profiles pair beautifully with the OBS output settings generator — generate each preset once, save as a profile, and never re-derive settings at the last minute.