You bought a CPE rated '-40 to 75°C' for an outdoor cabinet. Yet it still crashes in summer cycles. Why? Because 'wide-temp' on the spec sheet and the real conditions inside a sealed cabinet are two different things.
Wide-temp isn't just the chip
- The chip tolerates heat, but electrolytic caps don't — they're the weak link when hot.
- The PSU is the first part to die under sustained high temp.
- A metal shell conducts better than plastic, but needs insulation against shock.
Estimating in-cabinet temp rise
- In-cabinet temp ≈ outdoor temp + device heat rise (sealed cabinet usually +10-25°C).
- Summer 45°C outside + sealed cabinet → inside can hit 65-70°C, near the 75°C ceiling.
- Vent holes or a convection fan cut the rise by 15-20°C.
Derating advice
- Pick gear with a temp ceiling 15-20°C above reality for margin.
- Cabinet must ventilate or have a fan; without it, you need true -40~75°C industrial.
- Don't place the CPE right next to a sun-baked PSU; shade it.
Buying a wide-temp CPE but ignoring cabinet and cooling design is buying half the solution. Estimate the rise first, choose the gear after.
FAQ
How to choose 4G CPE antennas and ports?
External high-gain antennas improve weak-signal areas; check LAN port count, PoE, SIM slot.
Single-SIM or dual-SIM (failover) CPE?
Dual-SIM standby auto-switches when the primary fails; most cases single-SIM suffices, dual for redundancy.
What is PoE on a 4G CPE for?
One cable carries data and power—no separate PSU; ideal for ceiling/outdoor installs.
Is the max-device count (client capacity) usually overstated?
Look at concurrent connections and real throughput, not the advertised max clients.