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Small copper-clad spring antenna 17.5mm long 915MHz 2.15dBi 50 Ohm

Adafruit

Adafruit Simple Spring Antenna 915MHz 17.5mm 2.15dBi 50 Ohm

SKU CH-CWN7-NK94M

A compact 915 MHz spring antenna with 2.15 dBi gain and 50 Ohm impedance, 17.5 mm long, copper-clad for easy soldering to LoRa or RFM modules

  • Product typePrototyping Products
  • Easy soldering with copper-clad wire construction
  • Compact 17.5mm length fits tight enclosures
  • 15dBi gain boosts 915MHz signal range
  • 50 Ohm impedance matches standard RF modules
  • Compatible with 850-950MHz wireless receivers and transmitters

915 MHz spring antenna for LoRa prototyping

This compact spring antenna is designed for 915 MHz ISM-band projects using Adafruit RFM and LoRa breakouts, bonnets or Feather boards. Its 50 Ohm impedance and 2.15 dBi gain suit typical 850–950 MHz wireless modules. The copper-clad wire construction makes it straightforward to solder onto prototype boards or custom PCBs.

Passive component with no thermal or power

As a purely passive radiating element the antenna generates no heat, draws no current and produces no audible noise. It adds negligible load to the RF front-end of the connected module. Normal operation therefore imposes no thermal management or power-budget constraints on the host board.

Copper-clad wire simplifies integration

The supplied copper-clad wire allows direct soldering without additional connectors or adapters. At 17.5 mm (0.68 in) long the antenna fits into space-constrained enclosures and keeps the overall prototype footprint small. No extra mounting hardware, cables or configuration software are included or required.

How it compares

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Price $4.99
Cheaper than about 93% of the 170 comparable items (median $11.49).

Specifications

Product
Product typePrototyping Products

Questions about this item

How do I solder this 17.5mm 915MHz spring antenna to a Feather or breakout board?

Tin the copper-clad wire end, heat the antenna pad on the board, then flow solder while holding the spring vertical; the short 0.68" length leaves little room for repositioning once the joint sets.

Will the copper-clad wire need replacement or re-tinning after extended outdoor use?

Copper oxidises over time; if the antenna is exposed to weather, plan to re-tin or replace the wire when the surface dulls or green patina appears, otherwise the 50 Ohm match degrades.

At what transmit power does the 2.15dBi gain start to roll off during continuous operation?

The bare copper wire has no heatsink, so sustained output above a few hundred milliwatts warms the spring, shifting its resonance and reducing effective gain in the 850–950MHz band.

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