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Q&A Power amplifier for remote controller

The data sheet gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 wit...

posted 2y ago by Andy aka‭  ·  edited 2y ago by Andy aka‭

Answer
#4: Post edited by user avatar Andy aka‭ · 2022-09-10T13:11:13Z (over 2 years ago)
  • The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.
  • $$$$
  • > _Is there a way to calculate the approximate range of this remote controller?_
  • You can use the [Friis transmission equation](https://en.wikipedia.org/wiki/Friis_transmission_equation) to calculate the free-space link loss between transmit antenna and receive antenna. It's based on carrier frequency, distance and antenna gains. For a simple antenna (a monopole) you have an extra gain of 2 dB for each end. Anyway the formula for isotropic antennas (null gain) is: -
  • Link loss (dB) = 32.4 dB + 20log(MHz) + 20log(kilometres)
  • Putting you figures in (and assuming a 1 GHz carrier) we get LL = 32.4 dB + 60 dB + (-34 dB). That's a link loss of 58 dB in free-space. But, we should probably add another 20 dB for fading bringing us to 78 dB. Then because I'm assuming monopole antennas, this drops to 74 dB.
  • You then might ask whether your receiver is capable of working with this amount of attenuation. After all, if only 1 mW is transmitted, your receiver is only going to see -74 dBm and, is this enough?
  • Well, there's another generally used formula that ascertains how much power a receiver needs based on noise statistics, ambient temperature and receiver bandwidth. Bandwidth is usually swapped with bit rate. Formula: -
  • Minimum power = -154 dBm +10log(bit rate)
  • So, if your bit rate is 100 kHz then the minimum receive power should be greater than -104 dBm. And, if my numbers match your true numbers then 20 metres should be a breeze.
  • The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.
  • $$$$
  • > _Is there a way to calculate the approximate range of this remote controller?_
  • You can use the [Friis transmission equation](https://en.wikipedia.org/wiki/Friis_transmission_equation) to calculate the free-space link loss between isotropic transmit and receive antennas. It's based on carrier frequency and distance. For a simple antenna like a monopole, you have an extra gain of 2 dB at each end. Anyway the formula for isotropic antennas (null gain) is: -
  • $$$$
  • Link loss (dB) = 32.4 dB + 20log(MHz) + 20log(kilometres)
  • $$$$
  • Putting your figures in (and assuming a 1 GHz carrier) we get LL = 32.4 dB + 60 dB + (-34 dB). That's a link loss of 58 dB in free-space. But, we should probably add another 20 dB for fade-margin bringing us to 78 dB of link loss. Then, because I'm assuming monopole antennas, this drops to 74 dB.
  • You then might ask whether your receiver is capable of working with this amount of attenuation. After all, if only 1 mW is transmitted, your receiver is only going to see -74 dBm and, is this enough?
  • Well, there's another generally used formula that ascertains how much power a receiver needs based on noise statistics, ambient temperature and receiver bandwidth. Bandwidth is usually swapped with bit rate. Formula: -
  • $$$$
  • Minimum power = -154 dBm +10log(bit rate)
  • $$$$
  • So, if your bit rate is 100 kHz then the minimum receive power should be greater than -104 dBm. And, if my numbers match your true numbers then 20 metres should be a breeze.
#3: Post edited by user avatar Andy aka‭ · 2022-09-09T16:16:02Z (over 2 years ago)
  • The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.
  • > _Is there a way to calculate the approximate range of this remote controller?_
  • If you know the receiver minimum guaranteed sensitivity you can use the [Friis transmission equation](https://en.wikipedia.org/wiki/Friis_transmission_equation) to calculate the free-space link loss between transmit antenna and receive antenna. It's based on carrier frequency, distance and antenna gains. For a simple antenna (a monopole) you have an extra gain of 2 dB for each end. Anyway the formula for isotropic antennas (null gain) is: -
  • Link loss (dB) = 32.4 dB + 20log(MHz) + 20log(kilometres)
  • Putting you figures in (and assuming a 1 GHz carrier) we get LL = 32.4 dB + 60 dB + (-34 dB). That's a link loss of 58 dB in free-space. But, we should probably add another 20 dB for fading bringing us to 78 dB. Then because I'm assuming monopole antennas, this drops to 74 dB.
  • You then might ask whether your receiver is capable of working with this amount of attenuation. After all, if only 1 mW is transmitted, your receiver is only going to see -74 dBm and, is this enough?
  • Well, there's another generally used formula that ascertains how much power a receiver needs based on noise statistics, ambient temperature and receiver bandwidth. Bandwidth is usually swapped with bit rate. Formula: -
  • Minimum power = -154 dBm +10log(bit rate)
  • So, if your bit rate is 100 kHz then the minimum receive power should be greater than -104 dBm. And, if my numbers match your true numbers then 20 metres should be a breeze.
  • The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.
  • $$$$
  • > _Is there a way to calculate the approximate range of this remote controller?_
  • You can use the [Friis transmission equation](https://en.wikipedia.org/wiki/Friis_transmission_equation) to calculate the free-space link loss between transmit antenna and receive antenna. It's based on carrier frequency, distance and antenna gains. For a simple antenna (a monopole) you have an extra gain of 2 dB for each end. Anyway the formula for isotropic antennas (null gain) is: -
  • Link loss (dB) = 32.4 dB + 20log(MHz) + 20log(kilometres)
  • Putting you figures in (and assuming a 1 GHz carrier) we get LL = 32.4 dB + 60 dB + (-34 dB). That's a link loss of 58 dB in free-space. But, we should probably add another 20 dB for fading bringing us to 78 dB. Then because I'm assuming monopole antennas, this drops to 74 dB.
  • You then might ask whether your receiver is capable of working with this amount of attenuation. After all, if only 1 mW is transmitted, your receiver is only going to see -74 dBm and, is this enough?
  • Well, there's another generally used formula that ascertains how much power a receiver needs based on noise statistics, ambient temperature and receiver bandwidth. Bandwidth is usually swapped with bit rate. Formula: -
  • Minimum power = -154 dBm +10log(bit rate)
  • So, if your bit rate is 100 kHz then the minimum receive power should be greater than -104 dBm. And, if my numbers match your true numbers then 20 metres should be a breeze.
#2: Post edited by user avatar Andy aka‭ · 2022-09-09T16:14:48Z (over 2 years ago)
  • The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.
  • The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.
  • > _Is there a way to calculate the approximate range of this remote controller?_
  • If you know the receiver minimum guaranteed sensitivity you can use the [Friis transmission equation](https://en.wikipedia.org/wiki/Friis_transmission_equation) to calculate the free-space link loss between transmit antenna and receive antenna. It's based on carrier frequency, distance and antenna gains. For a simple antenna (a monopole) you have an extra gain of 2 dB for each end. Anyway the formula for isotropic antennas (null gain) is: -
  • Link loss (dB) = 32.4 dB + 20log(MHz) + 20log(kilometres)
  • Putting you figures in (and assuming a 1 GHz carrier) we get LL = 32.4 dB + 60 dB + (-34 dB). That's a link loss of 58 dB in free-space. But, we should probably add another 20 dB for fading bringing us to 78 dB. Then because I'm assuming monopole antennas, this drops to 74 dB.
  • You then might ask whether your receiver is capable of working with this amount of attenuation. After all, if only 1 mW is transmitted, your receiver is only going to see -74 dBm and, is this enough?
  • Well, there's another generally used formula that ascertains how much power a receiver needs based on noise statistics, ambient temperature and receiver bandwidth. Bandwidth is usually swapped with bit rate. Formula: -
  • Minimum power = -154 dBm +10log(bit rate)
  • So, if your bit rate is 100 kHz then the minimum receive power should be greater than -104 dBm. And, if my numbers match your true numbers then 20 metres should be a breeze.
#1: Initial revision by user avatar Andy aka‭ · 2022-09-01T18:01:41Z (over 2 years ago) 
The [data sheet](https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf) gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 with PCB layouts on following pages and sure, you can use any suitable antenna.