LowPowerLab Forum
Hardware support => RF - Range - Antennas - RFM69 library => Topic started by: joelucid on September 29, 2016, 09:24:02 AM
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When I measured some of my antennas against Moteino's I often found that a Moteino wire antenna would either be kind of ok or worse than everything else, depending on the orientation of the FTDI port: point the FTDI header to the gateway and the link will be much better.
I came across this article today: http://www.ipellejero.es/hf/antenas/monopolo/english.php#3, which contains a section on a l/4 monopole on a l/4 perpendicular ground counterpoise:
(http://www.ipellejero.es/hf/antenas/monopolo/Monopolo_1radial_estructura.jpg)
Leading to the following radiation pattern:
(http://www.ipellejero.es/hf/antenas/monopolo/Monopolo_1radial_diag_vertical.jpg)
(http://www.ipellejero.es/hf/antenas/monopolo/Monopolo_1radial_diag_3D.jpg)
It's not quite a correct model because the ground plane of a Moteino is much smaller than l/4. On the other hand connect you 9V battery to the FTDI header and you're about there. Anyway this helps visualize the issue.
Wanted to share because of the practical implications. In my experience you can boost RSSI by ~9 dBm simply by turning the Moteino.
Joe