I have been conducting propagation measurements with a network of about
15 mica2's, in which each node records the RSSI of its neighbors. I'm
using the standard quarter-wave monopoles that come with the mica2. I
had been having trouble keeping the antenna vertical, especially in the
wind, so I added a small rubber band between the antenna and the jumper
cable assembly (J4) to each node. After this addition, I notice that
the RSSI jumped by an average of 4-5 dB with the rubber bands, compared
to the case when all of the antennas were kept vertical without the
rubber bands. I spent some time calibrating each node's transmitter
power, and receiver RSSI characteristic, and it appears to me that in
fact the antenna has a significant loss when the rubber band is not
used. It would seem that the antenna connector (MMCX) does not provide
a very solid RF connection, and that holding it tightly into place
(with a rubber band) improves this connection.
However, this may be purely my set of antennas or connectors on my
mica2's. Has anyone else noticed similar effects on their nodes?
Thanks,
Neal
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