increase power of NRF24L01 radio

[pereczes]

POST REMOVED AT USERS REQUEST

[Whales]

Probably, but I'm not familiar with amplifiers in the Ghz.  I assume they are costly and need strict canning & PCB layout.

If your targets are not moving, using a higher gain antennae may be easier.  The kiwis have excelled at using this to pick up wifi from several Km away

[Marco]

How much amplification are you looking for? Elecfreaks has a version with small amplifiers (20 dB for transmit, 10 dB for receive I think).

[8086]

Sort of off-topic, but does anyone know why the Elecfreaks module only claims 1000m range in ideal conditions with +20dB gain, while the XBee Pro ZB claims 3400m range and +18dB gain?

Is it simply a case of...better engineering? They seem to otherwise be the same or very similar (data rate, etc).

[Whales]

Sort of off-topic, but does anyone know why the Elecfreaks module only claims 1000m range in ideal conditions with +20dB gain, while the XBee Pro ZB claims 3400m range and +18dB gain?

Is it simply a case of...better engineering? They seem to otherwise be the same or very similar (data rate, etc).

"Range" is non-scientific.  It can be anything they want it to be, depending on many other variables.

 Antennae gain values are approximates AFAIK -- their exact patterns are more complicated than a cone model.  *not an RF engineer*

EDIT:

When no direction is specified, "gain" is understood to refer to the peak value of the gain. A plot of the gain as a function of direction is called the radiation pattern.

[8086]

Sort of off-topic, but does anyone know why the Elecfreaks module only claims 1000m range in ideal conditions with +20dB gain, while the XBee Pro ZB claims 3400m range and +18dB gain?

Is it simply a case of...better engineering? They seem to otherwise be the same or very similar (data rate, etc).

"Range" is non-scientific.  It can be anything they want it to be, depending on many other variables.

 Antennae gain values are approximates AFAIK -- their exact patterns are more complicated than a cone model.  *not an RF engineer*

EDIT:

When no direction is specified, "gain" is understood to refer to the peak value of the gain. A plot of the gain as a function of direction is called the radiation pattern.

So you reckon they are simply referring to different points on their radiation patterns?

One being optimistic and one being conservative?

Still seems like a huge difference in range, wouldn't you think they would both use their maximum value?

[theatrus]

Chipcon/TI have a set of 2.4GHz LNA/PA combos which replace the balun for their radios. However it's going to be a bear making it work with the Nordic chip if you don't have RF experience and a VNA.

Edit: though I distinctly remember having a coworker make this work well enough on a product. But we had a VNA to tune in the design.

[ve7xen]

So you reckon they are simply referring to different points on their radiation patterns?

One being optimistic and one being conservative?

Still seems like a huge difference in range, wouldn't you think they would both use their maximum value?

More likely their definition of "range" is just different. Does it mean "distance in free space at which communication is still possible with a < 50% error rate" or does it mean "distance in 'real life' conditions at which communication at full speed with low error rate is likely"? I'd guess one or the other has a looser specification on what the expected data and error rates will be at full "range".

Anyway, you're kind of comparing apples to oranges here, since the XBee you're referring to is a ZigBee radio and the Nordic module is not. ZigBee is only 250kbps while the Nordic modules do 1mbit or 2mbit, this will add a fair bit of noise margin. The modems will also likely be implemented differently, and possibly the radios themselves have better (lower noise / more sensitive) receivers. This is clear from the specsheet sensitivity numbers - Nordic claims -85dBm at 1mbps, Digi claims -102dBm.

Really these numbers are marketing wank though, not an engineering specification, they can practically just make them up. There are too many, and too loosely-defined variables to glean anything other than order-of-magnitude information out of them. What you need to do is measure (or look in the specs, if provided) and find out what the minimum signal strength at the receiver is that results in acceptable performance for your application. Then you can estimate your antenna gains & path loss and figure out what an approximate range for your usage is going to be.

[8086]

So you reckon they are simply referring to different points on their radiation patterns?

One being optimistic and one being conservative?

Still seems like a huge difference in range, wouldn't you think they would both use their maximum value?

More likely their definition of "range" is just different. Does it mean "distance in free space at which communication is still possible with a < 50% error rate" or does it mean "distance in 'real life' conditions at which communication at full speed with low error rate is likely"? I'd guess one or the other has a looser specification on what the expected data and error rates will be at full "range".

Anyway, you're kind of comparing apples to oranges here, since the XBee you're referring to is a ZigBee radio and the Nordic module is not. ZigBee is only 250kbps while the Nordic modules do 1mbit or 2mbit, this will add a fair bit of noise margin. The modems will also likely be implemented differently, and possibly the radios themselves have better (lower noise / more sensitive) receivers.

Really these numbers are marketing wank though, not an engineering specification, they can practically just make them up. There are too many, and too loosely-defined variables to glean anything other than order-of-magnitude information out of them. What you need to do is measure (or look in the specs, if provided) and find out what the minimum signal strength at the receiver is that results in acceptable performance for your application. Then you can estimate your antenna gains & path loss and figure out what an approximate range for your usage is going to be.

Fair enough, I hadn't really considered that the radios themselves would make such a difference when the specs seem so similar.

Am currently deciding on a ~1km range wireless solution for a project so maybe I'll get some of the XBees and some of these cheaper ones and see how they compare in real life...

[theatrus]

http://www.ti.com/product/cc2591&lpos=See_Also_Container&lid=Alternative_Devices is the front end LNA/PA.

[theatrus]

Would trade the higher power against higher bit rate. This chip became much cheaper as nobody seems to buy it not even at price tag of 1$.

Thanks for the link. The CC2591 chip itself is not expensive, seems to be available for 1.50 if you buy tun. Wonder if it is just trivial to solder the terminals to a pcb.

A foto is available about the evaluation board.

http://www.ti.com/graphics/tool/cc2520emk_800.jpg

Btw: what is that balun? cannot find it on ebay/aliexpres

Then this level of RF work is probably not a project you are ready to tackle then. While it is a "small matter" of putting it on the board, all of the RF properties need to be considered, and this is not something you can measure simply with an oscilloscope.

For the curious, the adaptation required an RF transformer-balun and impedance controlled work (as expected for an RF section)

[Marco]

How much amplification are you looking for? Elecfreaks has a version with small amplifiers (20 dB for transmit, 10 dB for receive I think).

can you please post a link if possible?

http://www.elecfreaks.com/store/nrf24l01p-pa-lna-v20-p-142.html