# [SOLVED]Increase the Range of CC2500 rf module

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#### tushki7

##### Full Member level 4
How can i increase the range of cc2500 module? Do i need to attach an antenna or something?
And what type of antenna should i use?

Right now i am using it for indoor purpose only and it is sending data from 1 room to other which are merely 15-20 meters apart. Is there any way to increase its range?
here is the image of cc2500(from robosoftsystems) :

:roll:

#### chuckey

##### Advanced Member level 5
For the transmission side, power output X gain of aerial = ERP, effective radiated power. Then you have the path loss (distance), Then you have the receiving aerial X the minimum input power for the receiver to produce the wanted output, which must be in excess of the noise floor (hiss). So to increase the range you have 4 possibilities, increase the power, use a better transmitting aerial, use a better receiving aerial, use a more sensitive receiver.
To answer your question, find out the type number of the transmitting device, look up its specification. Then possibly increase the voltage on that device alone, this could increase the output power. Using better(bigger!) aerials will work but might not fit in the available space.
Frank

tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
For the transmission side, power output X gain of aerial = ERP, effective radiated power. Then you have the path loss (distance), Then you have the receiving aerial X the minimum input power for the receiver to produce the wanted output, which must be in excess of the noise floor (hiss). So to increase the range you have 4 possibilities, increase the power, use a better transmitting aerial, use a better receiving aerial, use a more sensitive receiver.
To answer your question, find out the type number of the transmitting device, look up its specification. Then possibly increase the voltage on that device alone, this could increase the output power. Using better(bigger!) aerials will work but might not fit in the available space.
Frank
I dont think there is any provision in the module to add an external antenna, also I don't want to ruin them. Moreover, i cant attach big antenna to them as i want to keep them compact for my application. Though i can use small antennas(Does it help?? shown in image) :
Is that true : By increasing input power to both of modules I can increase their range.. hmm ?
Ok first i'll try this and will be back to you soon !!

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Looking Forward for some more replies !!

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EhsanCompanY

### EhsanCompanY

Points: 2

#### E Kafeman

##### Advanced Member level 2
Shown retractable antennas are way too long. Most simple is to try to replace existing antenna with at upright standing monopole, length around 35 mm, which is a big antennas in this case. Current PCB antenna, if everything is well tuned, should give minimum 100 meter LOS coverage.
If not, improved impedance matching can improve performance as these modules are a bit tricky to set for best matching.
As CC2500 have balanced RF output can a dipole rather easy be implemented. Especially RX performance can gain of this, as it suppress ground related noise.
CC2590 (LNA and +10 dB PA) is a common complement if coverage is too short.

tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
Shown retractable antennas are way too long. Most simple is to try to replace existing antenna with at upright standing monopole, length around 35 mm, which is a big antennas in this case. Current PCB antenna, if everything is well tuned, should give minimum 100 meter LOS coverage.
If not, improved impedance matching can improve performance as these modules are a bit tricky to set for best matching.
As CC2500 have balanced RF output can a dipole rather easy be implemented.
Especially RX performance can gain of this, as it suppress ground related noise.
CC2590 (LNA and +10 dB PA) is a common complement if coverage is too short.

Sorry I didn't get your point (colored purple), can you explain it further?
After studying more about rf module, I came to know that it(CC2500) uses F type antenna, so this concludes i can't attach any other antenna on it.

#### E Kafeman

##### Advanced Member level 2
Between the RF output at CC2500 (two pins, balanced) and the antenna (1 pin unbalanced + ground) is a network consisting of a few capacitors and inductors that converts from balanced to unbalanced and adjust the rather complex impedance from CC2500 to something more like 50 Ohm at the point were antenna is connected.
You can use any antenna that fit your needs such as size, radiation pattern, gain, impedance.

tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
Shown retractable antennas are way too long. Most simple is to try to replace existing antenna with at upright standing monopole, length around 35 mm, which is a big antennas in this case. Current PCB antenna, if everything is well tuned, should give minimum 100 meter LOS coverage.
If not, improved impedance matching can improve performance as these modules are a bit tricky to set for best matching.
As CC2500 have balanced RF output can a dipole rather easy be implemented. Especially RX performance can gain of this, as it suppress ground related noise.
CC2590 (LNA and +10 dB PA) is a common complement if coverage is too short.

Thanks for your valuable reply, Can you explain it with an example or a circuit?

Between the RF output at CC2500 (two pins, balanced) and the antenna (1 pin unbalanced + ground) is a network consisting of a few capacitors and inductors that converts from balanced to unbalanced and adjust the rather complex impedance from CC2500 to something more like 50 Ohm at the point were antenna is connected.
You can use any antenna that fit your needs such as size, radiation pattern, gain, impedance.

tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
Looking Forward for some more thoughts, And i need some home made idea for purpose.

#### alexxx

##### Advanced Member level 4
tushki7 said:
Looking Forward for some more thoughts, And i need some home made idea for purpose.
It happens for me to be at the same position this period. You need an RF Front End Module for this, I don't know if you can do this in another way. I have also looked into CC2590, but still don't know yet which FEM is convenient for me. I am about to test SiGe's SE2436L in a few days, when I get the samples. I couldn't help you for the "home made idea", but from my experience until now, no series improvement could be made unless you use a FEM. I think I will also stay tuned on this thread . Below is the datasheet of the FEM I referred to earlier.

Alexandros

#### Attachments

• SE2436L_Datasheet_Rev_1 1_Oct-7-2011.pdf
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tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
I have also looked into CC2590, but still don't know yet which FEM is convenient for me. I am about to test SiGe's SE2436L in a few days, when I get the samples.
Alexandros

Please Do post your test results. I am still searching for some home made idea
And if i get some improvement in rf range, then i will post it here.

Looking for some more thoughts and other people experiences with such rf modules.
Thank you :?:

#### E Kafeman

##### Advanced Member level 2
What is your current coverage and how much do you need to improve it?
For your existing system based on CC2500 and existing F antenna, if good designed, should a coverage of at least 100 meter LOS be possible, even if bandwidth is set to max. Reducing bandwidth and coverage should be even better. I think TI have done some practical comparison att Analog, Embedded Processing, Semiconductor Company, Texas Instruments.
If coverage is reduced due to bad tuned design, should that be corrected. Adding more amplifiers on a unstable system can easy result in even shorter coverage.

tushki7

### tushki7

Points: 2

#### alexxx

##### Advanced Member level 4
tushki7 said:
The indoors range did not improved dramatically as I thought it would. I used evaluation boards for both microcontroller-tranceiver and FEM as well. The FEM board was CC2590EMK and the tranceiver was ATAVR128RFA1-EK1 kit. I couldn't figure out if I did something wrong. I used the control pins of CC2590 as datasheet suggested to get the high gain mode. The output power of cc2590 depends on its input power. The output power of ATmega128RFA1 is +3dBm. I was supposed to get around +20dBm. This is a very much improved power plus sensitivity fine tuning from the embedded LNA. The difference with and without the FEM indoors inside a heavy industrial enviroment was small. Far smaller than the all-in-one MCU-tranceiver-FEM module I was using until then, the ZigBit module which had better range. The antenna I used with those evaluation boards was a 2.4GHz rubber antenna, above 0dBi gain.

tushki7

### tushki7

Points: 2

#### biff44

##### Advanced Member level 5
You talk a lot about poor CC2500EM performance, but you do not tell us the parameters you are programming it with. What modulation (you want FSK or GFSK)? What frequency deviaiton (bigger is better for range)? What IF receiver bandwidth do you have set? What data rate and packet size? Have you checked to see if the transmit and receiver boards are on the same frequency, or are they many KHz off from each other?

tushki7 and alexxx

Points: 2

### tushki7

Points: 2

#### alexxx

##### Advanced Member level 4
biff44 said:
You talk a lot about poor CC2500EM performance
Thank you biff44 for your responce, but as I already said in the previous post "I couldn't figure out if I did something wrong". I did not say anything about poor performance in general, if manufacrurer says +20dBm I believe him. I was asked to give my results and I did and actually gave emphasis on the hard test enviroment as well.

PS: Sorry biff44, by reviewing your answer I just realized that this post was directed to the OP and not me. Sorry about that.

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tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
What is your current coverage and how much do you need to improve it?
For your existing system based on CC2500 and existing F antenna, if good designed, should a coverage of at least 100 meter LOS be possible, even if bandwidth is set to max. Reducing bandwidth and coverage should be even better. I think TI have done some practical comparison att Analog, Embedded Processing, Semiconductor Company, Texas Instruments.
If coverage is reduced due to bad tuned design, should that be corrected. Adding more amplifiers on a unstable system can easy result in even shorter coverage.

Till now, the range is about 15-20 meters(indoor). I bought CC2500 RF module from Robosoftsystems, they specifically mentioned the range of about : 60+ meters range Line of Sight / 30 meters range indoors.

The indoors range did not improved dramatically as I thought it would. I used evaluation boards for both microcontroller-tranceiver and FEM as well. The FEM board was CC2590EMK and the tranceiver was ATAVR128RFA1-EK1 kit. I couldn't figure out if I did something wrong. I used the control pins of CC2590 as datasheet suggested to get the high gain mode. The output power of cc2590 depends on its input power. The output power of ATmega128RFA1 is +3dBm. I was supposed to get around +20dBm. This is a very much improved power plus sensitivity fine tuning from the embedded LNA. The difference with and without the FEM indoors inside a heavy industrial enviroment was small. Far smaller than the all-in-one MCU-tranceiver-FEM module I was using until then, the ZigBit module which had better range. The antenna I used with those evaluation boards was a 2.4GHz rubber antenna, above 0dBi gain.

I tried with different power supply and no improvement yet!!! :???:
Now I'll try changing the frequency channels as it works between 2400 MHZ - 2480 MHZ. Will it help??
I am thinking of buying FEM module. From where can I get these??
What should be perfect height above ground for rf modules, I think it should be 2 metres?

You talk a lot about poor CC2500EM performance, but you do not tell us the parameters you are programming it with. What modulation (you want FSK or GFSK)? What frequency deviaiton (bigger is better for range)? What IF receiver bandwidth do you have set? What data rate and packet size? Have you checked to see if the transmit and receiver boards are on the same frequency, or are they many KHz off from each other?

As I mentioned in previous post, The rf modules I am using are CC2500 plug and play modules from robosoftsystems, So i don't have to program them for any FSK or GFSK. They are already Pre-Programmed to work on some modulation scheme (Curse : They didn't mentioned anything about modulation scheme or output power :x).
They work in between 2400-2480Mhz with channel spacing of 199.950000 kHz and total of 256 channels. Even I cant change the channel using my program as both of the modules needs to be preconfigured (so I can choose only one channel in which both the module work say channel 0 working at 2400 MHz). Variable packet length (0 to 40).
I am using two P89v51rd2 Micro-controllers for the purpose. Baud rate is 9600.
Here is Site link : http://www.robosoftsystems.co.in/roboshop/cc2500-wireless-module.html
Here is help file of cc2500 : View attachment Robosoft Systemsr 2.4 GHz RF ModuleT.zip

alexxx

### alexxx

Points: 2

#### E Kafeman

##### Advanced Member level 2
If I remember correct, CC2500 power output level can be set in 64 steps. Max +1 dBm when register is set to xFF.
Bandwidth is often set unnecessary wide which limits coverage.
If you not have access to these settings (you have, as you have the hardware and it is standard buses :wink: ) can it at least be measured with common RF tools.
A fixed channel frequency somewhere 2-3 GHz will cause diversity problems indoor due to reflections. It causes dead spots.
Whiteout knowing what kinds of walls etc. you have indoor, seems 20 meter coverage about what can be expected.
If these modules communicate from fixed points is the most simple method to increase communication distance to use directional antennas.
A CC2590 should increase communication distance at least from 20 to 100 meter if correct implemented.

tushki7

### tushki7

Points: 2

#### tushki7

##### Full Member level 4
Ok some Good news, Finally i Got some Improved Range when I adjusted Rf modules height about 3 meters above the Ground. Probably Now waves can travel with lesser Obstacle in the path and thus Low data loss. Now I can send data from one module to another which are about 30-35 meter apart; indoor with door close and they are not in line of sight(Position of two rf modules in room1 and room2 is like the starting and end point of alphabet ' L '~32 meters away). :twisted:
But one of my cc2500 stopped working, when i give power to it, it does not transmit or receive anything and after few seconds it gradually sinks whole circuit power, just like all of vcc connected to ground directly. Don't know what happened to it.
1.50 $from TI if you buy 1000pc. They can be killed due to ESD. Never touch its pins if you and PCB ground not is connected. tushki7 and alexxx ### alexxx Points: 2 Helpful Answer Positive Rating ### tushki7 Points: 2 Helpful Answer Positive Rating #### tushki7 ##### Full Member level 4 3.50$ **broken link removed**
1.50 $from TI if you buy 1000pc. They can be killed due to ESD. Never touch its pins if you and PCB ground not is connected. Their shipment will cost$40 here in India, I cant buy them!!! And right now i don't need them in bulk quantity, but Thanks for your suggestions.
Looking for some more suggestions, any other cheap products from India?

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