Does increasing the Decibel number mean more range in antennas?
2016-04-01 7:49 pm
Hi I don't really know much about antennas but I have a quadcopter and I was thinking about buying a new and more powerful antenna for it to increase the range and I found 5 and 10 dB so I was wondering which one would have range so does increasing the dB increase the range?
回答 (3)
2016-04-02 10:50 am
It's a bit more complicated than that. Quite a bit.
Antenna gain is (usually) defined in dB. As dB is a relative value, this is the antenna gain in the optimum direction compared to an isotropically radiating antenna. I.e. these antennas increase the power in one direction while decreasing the power in all other directions. "Direction" here may be a line or a plane. Which shows two problems with this:
1) the gain of the antenna is only there for a specific direction, the signal is weaker in all other directions. Not necessarily ideal for an R/C situation.
2) the legal limits on radiated power are based on an isotropical antenna. If you use a directional antenna, you would need to reduce the absolute transmitted power by the antenna gain on order to stay within the legal limits for radiated power (assuming that the original isotropic antenna was transmitting at the legal limit). Exceeding these limits can get you in _very_ hot water with the FCC (or whatever regulatory instance is responsible in your country).
In addition, 'the range' will depend on a lot of other factors, among them the quality of both transmitter and receiver, the transmission protocoll and the ambient level of other transmissions in that frequency band.
Antenna gain is (usually) defined in dB. As dB is a relative value, this is the antenna gain in the optimum direction compared to an isotropically radiating antenna. I.e. these antennas increase the power in one direction while decreasing the power in all other directions. "Direction" here may be a line or a plane. Which shows two problems with this:
1) the gain of the antenna is only there for a specific direction, the signal is weaker in all other directions. Not necessarily ideal for an R/C situation.
2) the legal limits on radiated power are based on an isotropical antenna. If you use a directional antenna, you would need to reduce the absolute transmitted power by the antenna gain on order to stay within the legal limits for radiated power (assuming that the original isotropic antenna was transmitting at the legal limit). Exceeding these limits can get you in _very_ hot water with the FCC (or whatever regulatory instance is responsible in your country).
In addition, 'the range' will depend on a lot of other factors, among them the quality of both transmitter and receiver, the transmission protocoll and the ambient level of other transmissions in that frequency band.
2016-04-01 8:29 pm
Let's start with a short explanation.
The decibel is not an absolute value;
it is a relative value.
If you had a sound system reproducing a test tone of 1,000 Hz (1 kHz)
at a volume that required 1 watt,
doubling the power to 2 watts would increase the volume by 3 dB,
which is considered the minimum change needed to be detectable by the average human ear.
To double the original volume, the power would have to be increased
by ten times (10 watts), which is a change of 10 dB.
Now, if you started with 10 watts instead of 1 watt,
a 3 dB increase would require 20 watts
and a 10 dB increase would require 100 watts.
That's audio.
For RF (radio frequency) applications such as your quadcopter,
the range would probably not increase very much
even with a 10 dB increase in signal ---
maybe anything from a few feet to several tens of feet.
If that's worth the cost of an antenna, go for it,
but something tells me that unless there's a material fact I missed,
you won't be overly impressed by the improvement, if there is one at all.
The decibel is not an absolute value;
it is a relative value.
If you had a sound system reproducing a test tone of 1,000 Hz (1 kHz)
at a volume that required 1 watt,
doubling the power to 2 watts would increase the volume by 3 dB,
which is considered the minimum change needed to be detectable by the average human ear.
To double the original volume, the power would have to be increased
by ten times (10 watts), which is a change of 10 dB.
Now, if you started with 10 watts instead of 1 watt,
a 3 dB increase would require 20 watts
and a 10 dB increase would require 100 watts.
That's audio.
For RF (radio frequency) applications such as your quadcopter,
the range would probably not increase very much
even with a 10 dB increase in signal ---
maybe anything from a few feet to several tens of feet.
If that's worth the cost of an antenna, go for it,
but something tells me that unless there's a material fact I missed,
you won't be overly impressed by the improvement, if there is one at all.
收錄日期: 2021-04-21 17:45:57
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