No USB Port Power on BBG


i want to use the USB Port of BBG to power my MLA-30 but it seems there is no power on the usb.

With external supply from via power bank the LNA of MLA-30 works...

Do i have to activate the usb port in linux somehow? In the schematic it looks like USB1_DRVVBUS has to be enabled?

73 de philipp, oe2aip


  • edited November 2020

    I have found the MLA-30 didn't work powered from the BBG USB port here but I had assumed that was some failure of the design rather than no supply to the port (will have to go get one and check..) .

    As the power injector for the MLA has a 5V-12V step up I didn't try again seeing that as a bit of an issue for HF. If you want to use it with the boost I'd split out the 5V before the Kiwi and try it there, the other advantage of doing it that way is some filtering between the MLA boost switcher and the RF side.

    Personally I would use another Bias-T and feed a linear voltage to the MLA avoiding the boost, it would probably run from a 9V battery that way.

    73 Stu

  • edited November 2020

    I had an MLA-30.

    Dump the 5-12V step up, and get a real bias-t injector from somewhere else and run it from 9-12V. The amount of RFI that the step-up converter caused was crazy.

    Don't forget to play with the gain control in the "antenna box", should be the only visible screw adjustment.

    Also it would help a lot to swap out the terrible coax it comes with for a real coax with lots less loss.

    I have stopped using mine since upgrading to this ( The MLA is moderately reasonable, but pales in comparison to the decent quality output from the Active-Antennas product.

  • Thanks for the answers. I tried to put 2x100 ohms in parallel in the bias-t where the rectifier diode for reverse polarity protection was located.

    Now it works with BBG. But yes, the step up DCDC makes a lot of noise... I will try to power it from 12V instead or maybe try active-antenne :-)

    73 Philipp, OE2AIP

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