New answers tagged

4

tl; dr: ZigBee isn’t a subset of WiFi (802.11). It is a different protocol family, just as Bluetooth is another different protocol family. ZigBee, BT and WiFi are not directly compatible with each other, but will co-exist in the same band. What Is ZigBee, And How Is It Different From 802.11, Really? ZigBee (802.15.4) is a family of protocols used for low- ...


3

They are completely different set of modulation and MAC layer protocols. From an RF point of view, WIFI has 20, 40, 80 and 160MHz channels (depending on the specific band and flavour), with DSSS or OFDM (depending on the flavour). ZigBee uses 5MHz channels.


0

Yes if the metal is ferrous it can cause problems. I worked a long time ago on a project where they mounted aerials for telemetry on moving carts on the iron chassis. The transponder failed completely. The iron basically soaks up all your flux - acts as a near short circuit.


3

Decibel, or dB, is a measure for a relation of two parameters. \$ Decibel = 10 \cdot log\frac{P}{P_0}\$, with \$P_0\$ beeing the parameter you compare your signal with. For calculating the gain of an antenna, you compare the recievable power at some point with the recievable power at that same point when a simple dipole antenna is used. When the power in ...


Top 50 recent answers are included