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QRP and portable radios
Small, low-power rigs for the field.
Small, low-power rigs for the field.
QRP means low power: by long-standing convention 5 W or less on CW, and 10 W PEP or less on SSB. A QRP radio is a small transceiver built around that power level, with a low current drain, so it runs from a small battery and fits in a pack. The same Q signal, "QRP?", asks "shall I reduce power?".
Signal strength depends on the ratio of powers, in decibels. Going from 100 W to 5 W is a factor of 20, which is 10 × log₁₀(20) ≈ 13 dB, about two S-units on a calibrated meter. The other station hears you that much weaker, and noise and fading hurt more.
You can win much of it back:
| Feature | Why it matters |
|---|---|
| Size and weight | Every ounce is carried up a hill |
| Receive current | Sets battery life, since most of the time you are listening |
| Bands and modes | A single-band CW rig is small and simple; a multimode multiband rig is more flexible |
| Receiver quality | Small rigs vary a lot; a quiet, selective receiver matters on a crowded band |
| Display and controls | Readable in sunlight, usable with gloves |
| Built-in keyer or tuner | Saves carrying extra parts; check what is included |
| Voltage range | Accepts a battery's range from fresh to nearly flat |
QRP rigs are the standard companions of summit and park activations (Summits on the Air, Parks on the Air), backpacking and emergency kits. Some operators build them from kits (Kits and homebrew), and there is a whole contest class for low-power stations. At home, QRP is a way to learn how much a good antenna and good operating can do.
Lower power does not mean no safety: batteries can start fires if shorted, and an antenna close to people still deserves respect; see Battery and fire safety and Batteries, solar and portable power.