I have some questions about the RX power sensitivity.
I have acquired some DWM1000 modules and I have 2 anchors and 1 tag.
I have configured the modules to transmit with maximum power (0x1F1F1F1F) but for some reason every day the RX power sensitivity varies by a lot.
My other settings are 110kbps/64MHz pulse frequency and 2048 preamble
When I measure on a distance of 10 meters one day I get -62dBm the other -78dBm and a other day -68dBm.
I’m kinda new with wireless communication so I donit know what affects it all.
Today’s weather is approx 25 degrees and 33% humidity. I forgot to record weather data with my previous tests.
My goal with these modules is to have the anchors at least 50 meters apart and the tag at least 120 meters from the anchors.
One day I can do everything no problem (-95dBm +/- 150 meter from anchor) and the other day I get stuck half way because my sensitivity is down at -105dBm +/- 80 meter.
Is there a way to configure sensitivity? Because the datasheet’s 290 meter is a bit off if you tell me.
What range do you get if you put the TX power to its legal max? (-41.3 dBm/MHz )
Disappointed range can have various causes,
It could be caused by HW design see APS017 Max Range In DW1000 Systems, and APH001 on DW1000 HW Design Disappointed range could also be caused by software or environment, see APS011 Sources of error in twr.
Finally, information on RX sensitivity can be found in the IC user manual, eg the chrystal trim section (8.1) and the RX section 4.7
All documents can be fetched from: https://www.decawave.com/
Thanks for your reply.
As I described before, I have the transmit power level to max. (register set to 0x1F1F1F1F)
I’m not sure if this setting violates the legal limit of transmit power.
Secondly, as mentioned before, I’m using the DWM1000 modules.
I hope that the modules have no bad hardware design which can affect my measurements.
Lastly, I’m having problems with my RX power levels. My ranges are within specification.
I’ve added an image that shows my test data, measured at 10 meters distance.
As you can see my RX power level varies from -56dBm to -75dBm.
Hi Kite Robotics,
Firstly, using the maximum transmit power setting isn’t advisable for a couple of reasons.
The DW1000 has alot of power headroom and the output with be way in excess of the regulatory limit
The transmitter amplifiers will start to go into saturation and the UWB signal could start to become corrupted.
I’d suggest sticking to the devices default power settings, which are listed in the DW1000 User Manual (Tables 19 and 20). From these, you would still need to fine tune each of your devices in calibration but with these defaults you will be close enough to the regulatory limit for your initial testing.
Regarding your varying receiver power level readings, I wouldn’t be too concerned about this as these are really just estimates and are know they differ from the real receiver power level at high levels, as is the case here (see User Manual Figure 22).
[color=#333333]Hi Kite Robotics,[/color]
I want to control the modules’ transmission power.And My approach is to control DWM1000 through SPI but this method does not seem to be feasible.
Could you tell me the method you take or give me some suggestions？
Without using maximum transmit power I’m not able to get my maximum range of 120+ meters, I’ve tried with default power settings but couldn’t manage.
I need to be able to get up to 120 meters, that’s why I initially asked if it is possible to adjust the RX sensitivity.
Can you please tell me why i shouldn’t be too concerned about my RX power level? For me now it’s an indication on what range I can get with these modules.
99% of the time it works like a treat, only 1% it is off and I want to make sure that it works 100% of the time.
But to bring your product to market you need to comply with UWB regulatory emissions limits. Transmitting at maximum power will cause you to fail emissions limits when your product is tested for compliance.
To get more range, maybe you could try the recommendations in app note APS017 on the subject. e.g. You can use lower channel frequencies or longer data rates. What antenna are you using? Can you use a directional antenna, which has higher gain?