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CC1310 - poor performance in range - only 50m

Other Parts Discussed in Thread: CC1310, SMARTRF06EBK

I've tested the new CC1310 with the pre-installed range test firmware on the SmartRF06 board. The test showed that the range was only about 50m at 868Mhz.

Receiver and Transmitter are 1m above ground. 

I'd expect to get at least a range of about 500-1000m. This should be possible as the advertisement states it is possible to get a distance of 10km!

What I am missing here? 

  • What HW do you use? Have you seen that it works as expected if measuring conducted? Is the front-end config on the HW matching the SW set-up? What antenna do you use?
  • >>What HW do you use?
    we are using two "CC1310DK":

    >>Have you seen that it works as expected if measuring conducted?
    not done yet. we don't have special hardware to measure here

    >>Is the front-end config on the HW matching the SW set-up?
    we are using the pre-installed range test firmware provided by TI. I expect this firmware to be programmed correctly.

    >>What antenna do you use?
    those that have been shipped with the CC1310DK (whip antennas)
  • What is the RSSI when you see that you start to loose packets? What is the RSSI if the devices are close, say approximately 1 m?
  • RSSI (1m): -46dBm
    RSSI (50m): -118dBm (packet loss 24 out of 261)

    I have made different tests and in one test I got a much longer range. The only difference to my other tests was that I disconnect/connected the antenna again. After testing again however, the performance dropped again. Really strange.

    I've checked that the antenna is fixed properly in all of my tests!

    Might there be an issue with the antenna connector on the C1310DK board?
  • To test the antenna, you could try to move the 0 ohm so that you use the PCB antenna instead.
  • The 0 Ohm is really tiny and close to the antenna connector :)

    But anyway, what is the expected dBm within the 1m-range? Shouldn't this value be around -20dBm?
  • -46 dBm RSSI at 1 m distance is too low. Did a measurement on my desk and got -15 dBm. With one antenna disconnected from the CC1310EM the RSSI was approx -57 dBm.

    I know the 0 ohm resistor is close to the antenna connector, but would be good if you could do the exercise so we can verify that the antenna is the problem. We will of course send you a new antenna if this proves to be the case.
  • Ok, I've now changed the 0ohm resistor to use PCB antenna -> -19dBm!

    So, the external antenna connector or the antenna itself might have a problem.

    I think it is the connector itself because I've tried with a different pair of antennas and I got the same problem.

    What do you think?
  • The board needs to be replaced. I have sent you a friend request with information on who to contact.

    Sorry for the inconvenience
  • Hello, I have a same problem. So I also changed the register to use PCB antenna. It was better.

    But I'm not satisfied the performance.

    I want to use the SKY65366-11 for 433MHz, which has two separate port(TX and RX) and CC1310 has common RF port.
    what can I do? Can I tied two separate port up? or can I use the RF switch for them?
  • Keith: You write that you re not satisfied with the performance. What performance do you get and what do you need?

    For CC1310 it's possible to use two single ended RF paths, one for Rx and the other for Tx (or with a network made for different frequencies). See as an example how this can be done.
  • Hi Mastermind, I just got mine two weeks ago and operating using the builtin test firmware as the others, in LRM mode, I get the same results and connection drops within 100-150 yards! roughly the same as the other guys... Where can I find the source code of the sample software that was preprogrammed by TI in these modules? How can I test the long range mode since 150 yards is useless!
  • Hi Nader,

    The LRM is supported out-of-the-box, so it's either a wrong FW (I highly doubt that), or something wrong with the module/s.

    Regarding potential failure of the module/s, could you please take a high resolution photo of the module (component side)

    so we could inspect any potential assembly defect of some component, or several components.

    Additional photo of the same but this time when external antenna is connected to SMA connector.

    Regarding source code, TI doesn't release the source code, however, follow this thread, may be it can be of a help to you.

  • Nader: Do you have 2 x SmartRF 06 boards?
    If so: Could you use SmartRF Studio, select the 50 kbps setting, set the chip in cont. Rx and see which RSSI you get when you you have the Tx side off (measure noisefloor)

    Also try a range test with the 50 kbps setting. Which RSSI do you get if the boards are 1 m from each other when you receive packets?

    I have done some range testing with 50 kbps myself and got a lot more than 150 m.
  • CC1310EM-7XD-7793

    920Z, 50kbps, RX Mode => RSSI = -108dBm

    868Mhz, 50kbps, RX Mode => RSSI = -99dBm

    is this normal?

  • No at all, unless of course the transmitter and receiver are separated by a 3m heavy concrete wall.

    Sounds like there something wrong with the antennas, or receiving/transmitting path.

    Could you make a photo of your setup and share with us so we could examine for potential faults?

  • I would check the antennas. Unfortunately we have had cases where the antennas in the kit are damaged. Are you able to check if this is the case and/ or run the testing with different antennas?
  • sorry i only have the two that came with the dev kit. How can I prove the antenna is the cause?

  • Hi Nader,

    You could re-route the RF path to the PCB helix antenna by rotating/soldering R11 (0R resistor) in place of R12, be careful though,

    0402 components and their pads are very delicate.

    I've marked the rotation/soldering point with the yellow stripe on the attached picture:

  • Hi Sverre, how are you?

    I'm having the same problem, we boght 3 pairs of CC1310EMK module, following the serial number:
    0000 01DD
    0000 016C
    0000 0257
    0000 01F3
    0000 023E
    0000 0207
    Connected to SMARTRF06EBK I can't reach more than 50m using the SMA antenna with default program.
    I'd expect to reach a better range than that.
    Based on the following test, can we know if these modules are working properly?

    *Test 1
    SMA antennas on the table.
    1 meter distance between boards.

    *Test 2 - Using SmartRF7
    TX SMA antenna and RX PCB antenna
    1 meter distance between boards.
    TX power 14dBm

    *Test 3
    TX SMA antenna, RX SMA antenna
    103 meters and walls between boards.
    TX power 14dBm

    *Test 4
    TX SMA antenna, RX SMA antenna
    408 meters and no obstacles between boards.
    TX power 14dBm

    thank you.
  • Correct me if I'm wrong but the difference between test1 and test2 is the type of antenna used on the Rx side? If that is the case it could look like one of the whip /SMA antennas has a defect since the RSSI level is better on test2. Have you done any range tests only using the PCB antennas? The efficiency is a bit lower on the PCB antenna compared to a whip antenna but it will show you if you have a issue with the other antennas.
  • Hi TER, thanks for your quick reply.

    The difference between the test1 and test2 is the antenna and the TX power, on test2 I used the software SmartRF Studio 07 and we used the default configuration for LRM in 915MHz, (Symbol rate 10.00061 Kbaund, Rx filter BW 39KHz, Tx Power 14dBm), Test1 was done using the default program "cc26xx-demo-for-CC1310.bin"

    Model: CC1310EM-7XD-7793-4L
    (4-layer, DK) Rev.: 1.0.1

    *Test PCB antenna (SN: 0000 0247) to PCB antenna (SN: 0000 01F3) - using the default program "cc26xx-demo-for-CC1310.bin"
    1 meter distance between boards on the desk.
    RSSI: Between -45dBm to -60dBm (Depending on the orientation)

  • RSSI of -60 dBm sounds low on 1 m distance. This is something I can get on my desk if I just use an antenna on the receiver and not on the Tx side.
  • Hello.

    Configuration: LRM, 915MHz, (Symbol rate 10.00061 Kbaund, Rx filter BW 39KHz, Tx Power 14dBm), Tests using the default program "cc26xx-demo-for-CC1310.bin"

    Model: CC1310EM-7XD-7793-4L       (4-layer, DK) Rev.: 1.0.1

    *Test 1

    SN: 0000 0257 PCI
    SN: 0000 01F3 PCI

    RSSI: around -44dBm

     *Test 2

    SN: 0000 0207 SMA RX

    SN: 0000 006C SMA TX

    RSSI: about -42dBm

    *Test 3

    SN: 0000 0207 SMA RX

    SN: 0000 006C SMA TX

    RSSI: about -40dBm

     *Test 4

    SN: 0000 0207 SMA RX

    SN: 0000 023E SMA TX

    RSSI: about -43dBm

     We tested a lot of combinations and different orientations, the performance still under what we were expecting.
    Is this lot and Rev.:1.0.1 ok? If not, how can I contact some kind of recall?

    Attached some details and pictures.

    Thank you.

  • Marcus,

    Where is this test being performed? What country?

  • Hi TA, thanks for your reply.

    I'm performing the tests in Brazil.

    Thank you.
  • Hi Sverre,

    We have a similar problem on two sets of CC1310EMK procured from Digikey last week. At 868MHz in LRM mode, we are seeing about -28dBm at 1m with the whip antenna, and about -21dBm with the onboard antenna. At 915MHz we see -48dBm with the whip and -36dBm with the onboard antenna. Range seems to be ~100ft before we lose most packets.

    What can we do to resolve this issue, and what sort of range should we expect with these evaluation boards?

  • Hi

    We bought from Digikey too. Probably it's a defective lot because the performance looks pretty lower than expected.

    What can we do?
    Thanks you.
  • To be able to compare I placed two EMs on a table with the antennas 1.0 meter apart. The tests where done using the 50 kbps using SmartRF Studio.

    I then got the following RSSI levels:
    868 MHz (whip antenna): - 21 dBm
    915 MHz (whip antenna): - 24 dBm

    Remove the whip antenna on one side: Between -74 and -80 dBm

    868 MHz (PCB antenna): - 30 dBm
    915 MHz (PCB antenna): - 33 dBm

    I have discovered that the whip antenna in CC13xx kit has a poor build quality. Have seen two type of failures, either the tap that should fit into the SMA connector is pressed in giving a poor contact or the metal inside the antenna breaks. If you have access to some other antennas, try those. Unfortunately the PCB antenna on the board has a fairly narrow bandwidth and it's not possible to have good performance at 868 MHz and 915 MHz at the same time. The goal is to have suggested values for matching network by mid next week to give better performance @868 and 915MHz.

    Loren, Tardi, are you able to measure conducted output power?

    Loren, do you get the same numbers using SmartRF Studio? The match does not change a lot from 868 MHz to 915 MHz so you should not get a big RSSI delta between the frequencies.
  • Hello,

    We are looking at using the 1310 for a new design but I want to make sure that the device will support ranges out to 2km open field.
    What should I do regarding purchasing development kits? Are the supplied Antennas truly defective?


  • The supplied antennas unfortunately have poor build quality. That said most of them will work just fine but we have seen examples where they have been broken. When you buy a development kit, test the kit with 1 m distance between the antennas first to see if you get good RSSI values. If you do you should be able to get 2 km, if you get poor RSSI values it's probably one or two of the antennas that are not too optimal.
  • Hello,

    The range achieved with the TI 1310 Development Kit is very low. I am facing the same issue as described in this thread. The RSSI Levels at a 1m distance with the provided whip antenna is as follows:

    868Mhz 50Kbps : -32dBm LRM: -37dBm
    915Mhz 50Kbps: -58dBm LRM: -59dBm

    Could you please suggest a fix for this problem? Whom do I contact to get a replacement kit?
  • Could you please do a test using the PCB antennas on the EM board by rotating the 0 ohm resistor?

  • Hi,

    We ordered another set of the CC1310 Development Kit. We were able to achieve RSSI levels of -19dBm with the new boards. Additionally, we tried the new antennas with the old boards to get good RSSI levels of -19dBm. With this, We believe that we can conclude that the old antennas are faulty.