Disadvantages of Chinese WIFI booster (amplifiers) WIFI

  • SP3OSJ

    Hello Arthur, you are right, but I doubt that this missing L in the VCC1 line is leading to an under-performance of the PA.

    It is just less "protection" against unwanted HF in the VCC1.

    73 de Johannes

  • SP3OSJ This point does not seem to be in the signal path. Instead it looks to be a supply line, so the inductor is nice....but probably not necessary.

    When I tested this board, I did not check the gain mid band. I wonder if the amplifier is just working too close to the band edge? Can you measure this and let us know? Perhaps it could be tuned a little.

    Thanks for the info 73 David

  • As previously commented the lack of the inductor is probably not important.

    Some time ago I modified one of the “8W” amplifiers so that I could test each amplifier chip on its own. Connecting directly to each chips input and output, bypassing the input and output combining circuitry and essentially testing as shown in the data sheet. The results for gain and output power for each chip were very close to the data sheet figures. So I came to the conclusion that the poor performance was down to the input and output combining circuitry and rf switching. I didn’t investigate any further as I no longer needed to use the amplifier.

  • Hi all

    I have measured about 2 dB higher gain on the "4W" than on the "8W" amplifier. I believe it is due to difference in loading impeadance of the two active devices - which are visibly different. When designing amplifiers you can chose to maximize Pout or Gain - or have some compromise in between. I believe there is a reason for the two versions to exist.

    73 Ole

  • According to my opinion, there are two reasons:

    The power supply does not give so much power 5.6V/need: 3A.

    The 3n3H coil used in the amplifier 4W size 0608 has a maximum current of 300mA and the transistor needs up to max 1.5A

    The 8W amplifier has a coil of PCB