Hi
I have a set up of a nrf24l01+ receiver and transmitter. The range isn't as good as I would like, but there is nothing I can do about the transmitter - it's encapsulated in a small space, which means compromises on the power and the antenna. I have set the bitrate to the lowest possible.
My question is: will I get a better range if I use a receiver with an external antenna?
The short answer is, "possibly".
It depends on what range increase you need. Is a fixed directional antenna a possibility or do you need it to be omnidirectional? The higher the antenna gain the more directional it will be.
Give us some more information.
Russell.
It needs to be omnidirectional. The antenna in the transmitter is simply a 30mm length of copper wire in a spiral which is hard up against a supercapacitor. (I've tried chip antennas but they seem no better) If the supercap is between the antenna and the receiver then I get a range of about 1.5-2m which is barely adequate. If the supercap is not in the way then I get about 5m which is fine. I can't control the orientation of the transmitter, which is liable to change. As I say, modifying the transmitter unit is not an option.
However at the moment the receiver boards I am using are just the ones with a PCB trace antenna so I am hoping that an external antenna will help.
The antenna in the transmitter is simply a 30mm length of copper wire in a spiral which is hard up against a supercapacitor.
That sounds totally wrong for a 2.4Gz transmitter. That'd be more for a lower frequency transmitter:
17cm for 433 MHz, 23cm for 315 MHz, so 30cm for even lower.
Look at the PCB antenna and SMA connected antenna used on nrf24l01+ modules here for comparison:
http://yourduino.com/sunshop2/index.php?l=product_list&c=12
I don't recall seeing any simple wire antennas like that in Nordic Semiconductor documents.
No, its 31mm not cm - that is right for a quarter wave, no? It's also the approx length of the PCB trace antennas on the cheap boards.
Sorry, misread that.
What kind of tuning components are there between the chip and the antenna?
Only what is on the PCB module, which is essentially the same as the modules which incorporate a PCB antennas - except without one.
I think you need to review some of the tuning articles from Nordic Semiconductor here:
click the Downloads tab, look at the White Paper section.
from nWP0017, for example:
A single-ended monopole antenna works together with the ground plane to form a dipole antenna. Consequently, the ground plane can be described as the ‘second half’ of the antenna.
You've changed the ground plane configuration from the PCB trace antenna, thus tuning is needed.
- Methods of tuning an antenna
There are the following two methods to tune an antenna:
• If the physical dimensions of the antenna can be altered, for example, with a PCB antenna,
adjusting the length will be one part of the tuning. Another part is to add a component,
inductor, or capacitor, to pull the antenna impedance towards the 50 ohm center point.
• If the antenna cannot be altered physically, more external components must be used to
tune the antenna. These external components are called the matching network.
8 Examples
To better explain how the impedance matching is done, some examples are needed. Section 8.1 shows how to match a chip antenna and section 8.2 on page 33 shows how to match a ¼ wave PCB antenna.
No examples given for a simple wire antenna.
I think your best bet would be to contact Nordic and ask for suggestions.
Thanks. There may be some improvements to be made through tweaking, if I make another one, but in fact I find that my simple wire antenna performs hardly worse than the trace antenna. The drop off comes when it's facing the wrong direction. Hence my request for information about external antennas for receivers. Anyway I have ordered one and will see what happens.
Adding a commercial whip antenna may not improve the situation, if the impedance of the antenna is not matched to the antenna port of the transceiver. You really need to study the material linked in Crossroad's reply #7.
Alternatively, buy a module with antenna to use as the receiver. Although these things are becoming ridiculously cheap, presumably the designers have at least attempted a proper impedance-matching configuration: Arduino 2.4G NRF24L01+ Wireless Transceiver Module + SMA Antenna Microcontroll | eBay
polymorph:
2.4GHz 11dBi omnidirectional antenna
I am a bit dubious about their claim of 11 dBi. From the size of that antenna it is likely to be a collinear array of four dipoles giving a theoretical gain of 8 dBi.
Russell.
Or a single dipole in a longer enclosure, with an even more exaggerated advertising claim.
See attached photo of a handsome, counterfeit capacitor.
It is advertising. Meh.
Here is another one: a "long range" Bluetooth module from DX.com, with a fake antenna. Adjust for best reception!
(photo on scanlime.org)
Russell.
jremington:
Here is another one: a "long range" Bluetooth module from DX.com, with a fake antenna. Adjust for best reception!
(photo on scanlime.org)
What's the world coming to?
Oh - hang on, I think I know. 
I was about to mention the problems in connecting an external antenna to one of these "on-board" ones.
Firstly, you cannot just connect the two together as you will be altering the impedance and the pattern of the external and internal ones are likely to interfere.
Secondly, given that you do disconnect the on-board one, you probably have no idea of the impedance at the point you connect into. It is more than likely not 50 Ohms.
Hello folks,
I bumping this whole thread up because I'm interested about what did the @p and others achieve distance wise from this Nordic semi product.
Since the thread there are new versions come out with noise amplification, external antenna.
Mine is the following:
People are claiming 2KM ... 31 km :o :o :o and other ranges with these commercial antennas.
I would only need 1km in clear line of sight and this PA PLNA with its hiper super antenna can barely do it. Actually I was even surprised to managed to get 1-2 packets through from a device using only 3.3v what transmitting power can you expect.
My setup was I sshed into my raspi from my iphone which was 1km away and had the other end of the transreceiver program running, while I went out with the transmitter to the desired spot. I had to be exactly at a right spot to get 1-2 packets (not constant communication), if I moved the antenna justa bit 20-30cm away I got absolutely nothing.
I boosted up the TX power to max and lowered the bandwidth as it was suggested from the manual so I looking for other suggestions here.
Would adding a windsurfer type of antenna or cantenna (Wi-Fi Cantenna (2.4GHz): How-to Make a Long-range Wi-Fi Antenna), just what you would build for wifi help? Well even so I could not leave that outside for years in harsh weather conditions. I need directional setup, the transmitter and receiver will never be moved.
No.
Parameter item
Parameter details & description
1
Size
18 * 33.4mm
2
Components
Imported from Japan, USA & Germany
3
Connector
242.54mm
4
Supply voltage
2.0 ---3.6V DC (Notes: the voltage higher than 3.6V is forbidden.)
5
Communication level
0.7VCC-5V(VCC refers to the supply voltage)
6
Operation Range
About 2100m(test condition:clear and open area& maximum power,antenna gain: 5dBi,height:> 2m,air date rate: 250Kbps)
7
Transmitting power
Maximum 20dBm(100mW)
8
Air data rate
Can be configured to 250k,1M,2Mbps
9
Sleep current
1.0uA(nRF24L01P sets as power-down)
10
Transmitting current
130mA@20dBm
11
Receiving current
20mA(CE=1)
12
Communication interface
SPI
13
Transmitting length
32 bytes (maximum) for one package, 3 level FIFO.
14
Receiving length
32 bytes (maximum) for one package, 3 level FIFO.
15
RSSI support
N/A(support simple data packet loss statistics)
16
Antenna type
SMA-K(External thread hole)
17
Operating temperature
-40 ~ +85
18
Operating humidity
10% ~ 90%
19
Storage temperature
-40 ~ +125
robertjenkins:
Hi
I have a set up of a nrf24l01+ receiver and transmitter. The range isn't as good as I would like, but there is nothing I can do about the transmitter - it's encapsulated in a small space, which means compromises on the power and the antenna. I have set the bitrate to the lowest possible.
My question is: will I get a better range if I use a receiver with an external antenna?
What is the transmitter encapsulated in? 2.4GHz doesn't tolerate such abuse I suspect, may be losing 10dB or
more into the encapsulating material.
Any external receiving antenna is a balance between antenna gain (relative to the PCB ant), and coax loss in
the cable to the antenna. At 2.4GHz cheap coax is horrendously lossy.
The two sites need to be 'line of sight' = more or less what it says, no buildings, hills etc in the way (if there are a repeater node might be suitable if you have permission to do so).
I would try 2x wifi yagi antennas and point them at each other. Use the pa/lna module and keep the shortest co-ax length you can. Higher is better in most all cases for the antenna.