The nRF905-EVBOARD

[Suleyman]

Hello,

I've purchased 2xnRF905-EVBOARD
I made some test with a spectrum analyzer. The output of the module is nearly 10dBm as mentioned in the datasheet. I connect the antenna given with The nRF905-EVBOARD. In transmit mode along the antenna output power is -5dBm. Maybe this can be relative not real power. I make test procesure everything fixed in place and try to increase the power radiated from the antenna. Seems impossible to even get to 0dBm. I purchased several 868Mhz antenna in order to test. same results. What I should do to increase the radiated power with nRF905-EVBOARD. I know that if I can increase the power measured from the antenna to 0dBm my range will increase. At least I should get about half of the power feeded to the antenna am I right ? Getting 10dBm power from the module and getting nothing from the antenna is deceaving. any suggestions.

best regards

[Suleyman]

Hi, Ok I don'have anechoic chamber, but nothing prevent me doing relative measurement. I set the spectrum to fixed place and measure the values by an antenna (tuned to 868MHZ) connected to the spectrum analyzer. The antenna ot the transmitter and antenna connected to spectrum is 1cm .I do all my measurent at the same place same distance, even the board place on a fixed place. İnjecting 10mw of power to the antenna , and getting 1/20 of from the antenna (All parts are from eval kit , this can be seen by the range test as well compared with different brand 868Mhz chipsets). I did same measurement with different vendors transmitters. with same setup same distance. same place etc. I can see the bare difference .say the output of the chip is 16dBm directly measured with cable. with antenna the antenna at 1cm distance I get 11 dBm. From these comparative experiment I may say that the nrf905 eval board is not enough efficient. Then not enough to make evaluations. I think that nordic should provide anechoic chamber measurement in order to make real evaluation.

with my nrf905 I did about 50m range with obstruction. with the 16dBm module I get about 300m with obstruction. I need about 300 meters range line of sight) for my application which will be in industrial application like remote crane control ( we produce remote crane controller since 2006 about 50000 pcs of nrf2401A functionning in the market)

some suggestions please.

best regards