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LAUNCHXL-CC1352P: Comms range test

Prodigy 50 points

Replies: 7

Views: 123

Part Number: LAUNCHXL-CC1352P

Hi,

I'm using 2 launchpads, a launchxl-cc1352p1 and a launchxl-cc1352r1 to test the LOS range at 868MHz.  Setup is as follows:-

- both set to 868MHz, 50kbps, 2-GFSK, 25kHz deviation, RX filter BW 98kHz

- launchxl-cc1352p1 is running the rfPacketTX firmware, and TX power is set to 20dBm

launchxl-cc1352r1 is attached to laptop running Smartrf Studio7 in RX mode

What I'm finding is that LOS range is approx 70m.  I was expecting a much higher range given that papers I've read say that subGHz is meant to have a range >1km.  Are my settings wrong?

Thanks

tc

  • Guru 227235 points
    You can use www.ti.com/.../rf-range-estimator to estimate range.

    - How are the LPs positioned when doing this test? Placed on what, how high above ground?
    - If you have the TX side turned off, how high is the background noise if you set the RX side in cont. RX?

     Out of office, back 20.06

  • In reply to TER:

    Hi TER,

    Some details on what I'm doing...LPs are held at a height of approx 1.5meters, with one taped to a plastic pipe and the other taped to a cardboard box.  The LP pcbs are positioned in the vertical plane with the PCB antenna at the top.  The LP-cc1352p1 is transmitting and is in a fixed position on a street.  And I walk down the street with LOS, holding the LP-cc1352r1 (receiving).

    The results in my previous post were at 868MHz and running the smartRF continuous RX indicated the upper limit of the noise floor to be about -70dBm.  I was only getting a distance of around 60-70meters.

    I had a look at 915MHz, and running the smartRF continuous RX indicated the upper limit of the noise floor to be about -90dBm.  I was able to get to about 130 meters LOS with a PER of <10%.  This time, I used Smartrf studio at both ends to do this test at 915MHz, with the same settings as in the previous post, except for the 915MHz freq of course.

    Thanks

  • Guru 227235 points

    In reply to tc:

    A noise floor of -70 dBm is very high. In the range estimate excel sheet I linked to it's possible to input the background noise floor to see the impact on the range as a function of noise. Where in the world do you do the range tests?

     Out of office, back 20.06

  • In reply to TER:

    I'm in Australia, so should be using 915MHz, hence the high noise floor at 868MHz . So please ignore my 868MHz results, but for 915MHz with a -90dBm noise floor I'm still only getting 130meter range. This is my own adhoc testing done near my work office, not done at a professional test site. The purpose of my testing was to get a feel for LOS range and then RF performance in areas with buildings/obstacles. I'm been using wifi at 2.4G and have been having coverage issues so was hoping subGHz would provide better coverage/range.

    Have TI done some "real world" range tests with these LPs? And what were the results? As I stated previously I was expecting much longer range, as in >1km - is this a wrong expectation on my part? Any suggestions on what I can try?
    Appreciate any help.
    Thanks
  • Guru 227235 points

    In reply to tc:

    When I use the range estimator I linked to you should be able to get ~650 m LOS based on the parameters you are giving. Not sure why you are getting a lot less than this.

    - Do you see a difference if you test a place free from buildings? It could be some reflections or interferers that potentially impact the result.
    - Could you try the 5 kbps Long Range Mode and see if you get better result?

    We have done very limited testing in the field with these LPs. We plan to do some tests, starting in about 4 weeks. The challenging part with range tests is that they are just valid for where and when the tests are done since the surroundings impact.

     Out of office, back 20.06

  • Genius 15490 points

    In reply to TER:

    Hi,

    The noise floor you are measuring is very high and the range is really poor. 70 -130 m is a clear indicator that something is wrong here.

    Do you have a 4G phone / strong interference working in close proximity of the Rx unit ?

    Are you positioning/holding the LPs so the antennas are detuned ?

    Best radiation / range from the boards is when the LPs are facing each other so the effective antenna area size is as large as possible. If the edge of the boards are facing each other, then this will give a lower range but still should be way better than 70 - 130 m at 868/915 MHz. 

    Make sure that you are using the latest version of the SmartRF studio so the xtal tuning is correct for the LPs. 

    Do you have access to a SA ?

    If yes, then ideal to measure the output power and the frequency offset on the LPs.

    Measure the NF in a 100 kHz bandwidth with the SA. 

    Regards,

       Richard

     

  • Guru 227235 points

    In reply to RGW:

    TC: Have you been able to do new tests?

     Out of office, back 20.06