Hello, I am using 2 small serial transceivers (from Active Robots). Included were 2 (2 inch) stub antenna. Before I waste my money.... If I buy 2 larger "rubber duck" (8 inch) antenna (with increased db), will I increase transmission range even though I won't be increasing wattage output of the transceivers?
Thanks for your time Richard
Assuming:
1) The larger antennas were designed for the frequency you're using 2) The receiver can still "see" the transmitting antennas (a higher gain antenna simply takes the energy provided to it and concentrates it into a narrower region, just like a lens -- for the antennas you're using, the regular bagel-shaped radiation pattern gets "squished" into a flatter bagel)Then, yes.
Note, however, that often variations in received signals due to your 'bot or people moving around can easily be +/-10dB or more, and therefore for antenna gains you can reasonably obtain (2dBi->8dBi), you can take a system that receives a *lot* of bit errors and reduce their frequency, but usually you don't go from "lots of errors" to "no errors."
Just as an aside, increasing the transmitter power (what the OP alluded to as 'wattage') doesn't yield a whole lot (as I know Joel is aware, but the OP may not be, and that's who I'm addressing) unless you increase it a LOT.
If you get (for instance) 3dB better sensitivity with your antenna, it's equivalent to doubling the transmitter power (assuming identical radiation patterns).
For a perfectly isotropic antenna, to double the range of your system by increasing the transmitter power, you *square* the transmitter power. That's why we try to get the increased sensitivity in the receiver - simpler and less likely to make a space heater :)
Cheers
PeteS
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