Antenna options
Moteinos are provided with a 1/4 wavelength Monopole wire that should be soldered to the ANT pin. Each frequency has a specific antenna wire length. You should not use the transceivers without any antenna attached or there will be no range and you risk damaging them. The default basic Monopole wire has an excellent performance to cost ratio. You may have increased performance and signal strength using a Dipole antenna (1/2 wavelength).
There is now a wideband PCB Dipole available for 868-915mhz:
You can also solder SMA or U.FL connectors and hook up other types of antennas:
On older Moteinos you can carefully solder u.FL or SMA connectors between the ANT pin and GND:
Range is difficult to specify or estimate because signal propagation is influenced by factors, including the radio software parameters. Range tests are typically performed in open air. Note that atmospheric conditions can also have an impact on signal propagation (humidity, rain, snow etc). Even with the simple Monopole antenna, the range can reach beyond a mile in open air.
RFM69HCW is a higher power version of RFM69CW (20dBm vs. just 13dBm) and thus it can reach significantly further. Other users have done some experiments and have reported various ranges:
- RFM69W @ 55.5kbps with 1/2 monopole: 400m+
- RFM69HW @ 1.2bps with dipole: 1.5miles !
- RFM69HW @ 38.4kbps: 560m+:
- Some forum users have achieved many km of range by tweaking the stock RF settings!
Here is an example range test of 2.5Km with stock Moteinos and some interesting BiQuad antennas, build details in the forum:
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