Anonymous
  • I've done some more testing over weekend.

    I've set LRM with 625 bps on 915 Mhz. I've used LRM default parameters from SmartRF Studio 7:

    RX Filter BW 39 kHz

    TX Power 14 dBm

    Symbol Rate 10 kBaud

    Deviation 5 kHz

    No whitening.

    The launchpad was in vertical position during testing. The testing was done in  a suburb area with mix of 1-2-4 stories buildings.

    I've seen some improvements compare to my previous test.

    The good quality reception was limited by ~150 m. I was able to get signal at 290 m, but it was not a reliable one.

  • Times were different then, . Our world has changed.

  • You could have warned me when you took us on that walking tour.

    God knows they would have thought about the water bottle. ....

  • Thank you for the information. Yes, I saw the video from South Africa (they've used a different chip).

    I'll try to go over "Range Debug Check List" from Excel sheet to estimate range for Indoor and Outdoor over the weekend.

     

    On other side, it supports mesh network. It should be a good workaround for a an environment with lots of heavy interference. But with just two kits it is impossible to test.

     

    Have somebody tested mesh network with CC1310 with the objective to extend network range/coverage?

  • Jon Clift wrote:

     

    ...[or, even better, a tethered drone a few hundred metres up - would that be legal where you are?].

     

     

     

    Brussels is not the place to walk around with antennas these days. The last time a student tried to measure mobile phone range for his studies, he was held under shot by the army for several hours (see link below):

     

    Student die grote politie-operatie uitlokte in Brussel, is v... - Het Nieuwsblad Mobile

     

    Photo: BELGA - fair use

     

    I'm not too keen to walk with my mobile antenna device on the streets around here. It's not the right time and place to do that. Let alone  a drone

     

     

    Photo: VRT - fair use

  • Jon Clift wrote:

     

    Having the LCD ahead of the antenna, like you show in the photograph in the comments to that post, is an awful placement. Your hand isn't placed very well, either.

    That wasn't how I tested it on the street. I made a carton gizmo where the battery and the display were not in front or at the back of the antenna:

  • Having the LCD ahead of the antenna, like you show in the photograph in the comments to that post, is an awful placement. Your hand isn't placed very well, either. What's the interface to the LCD? If it's only a few wires (SPI or I2C), you could easily move it out of the antenna's near field. As to your hand, just hold the board at the usb end with the folded element pointing up rather than down - the radiation pattern will invert, so you'll still have the same power coming out in the horizontal plane.

     

    The street test is a tough one. As well as ground effects and the absorbtion through the buildings when you turn the corner, you've also got multi-path reflections to contend with [I can remember reading that when they first developed the cellular networks, on frequencies similar to what you're using here, they had to do a lot of work to contend with multi-path interference from the buildings in city centres]. The most obvious immediate thing you can try is to get the base station higher up - maybe a separate antenna on a pole at the top of the building [or, even better, a tethered drone a few hundred metres up - would that be legal where you are?].

     

    As far as the mobile station is concerned, perhaps you could get a hat (maybe like the one Shabaz is seen wearing) and fasten the antenna to the top of that (that's a joke - I just like the idea of you wandering around with an antenna on your head).

  • Jon Clift wrote:

     

    How did you have to orientate the board in order to get the best range? Was the folded element pointing straight up? [I'm trying to guess based on my limited knowledge of rf.]

    Both vertical, with the PCBs parallel (is the right term planar?) to each other as I was walking.

    As soon as I took the corner at spot #2, the signal had to go trough a number of houses.

    At the corner there's a big antenna of the public transport organisation. They operate their private communication network in the city.

     

     

     

    In the signal strength post  you can see a map with many of the other influences (radio/tv communication tower, airport, nato all in direct vincity). It's a rough area for radio signals.

  • Hey, , thanks for the link to that spreadsheet!

    I have 2 of the antennas that are used in that spreadsheet at home:

     

    DN024 - 863-928 MHz (CC_Antenna_DK2_#9)

     

    I can give it a try...

  • Sergey Vlasov wrote:

     

    And in vertical position the range should be more then ~2 km vs. ~1 km in horizontal position with Tx conducted output power 14 dBm with no interference power level (at antenna port) and datarate (sensitivity level) set to Long Range - CC13xx 2.5 kbps (LRM) as per Excel sheet to estimate range for Indoor and Outdoor

    But if datarate (sensitivity level) set to 4Mbps with all other parameters without any change then range gets reduced to ~100m.

    I did my test on 6xx bps LR, 14 dBM, antenna vertical. But in an environment with lots of heavy interference.

    It was intended as a real world test. And the results weren't very different from those of in a similar urban environment.

     

    I bet that if you do the measurements in ideal situations you get the same range as the datasheets. There are a few videos on youtube of people that beat those ranges. But they do that in nature (Norway and South-Africa's coastline), from hilltop to hilltop. That's a different setting than in a capital, with the most powerful antennas of the country in line of sight and the airport in hearing distance...