KiwiSDR 2 voltage sensitivity

techn0madtechn0mad
in Problems and Issues

Hi all:

After having it sit on my desk for a number of months, I've finally gotten some time to get my KiwiSDR 2 setup, and I've noticed something odd. Digging through my junkbox I found an adapter that could provide 6V at about 2A, with a 2.1 mm connector. When I connected it to the KiwiSDR 2, nothing happened. Just to calm myself down, I grabbed the power supply I've been using with my old KiwiSDR and plugged it in. The KiwiSDR 2 booted up and blue lights began appearing here and there. More digging through the junkbox and I found a nice cable with a 2.1 mm connector on the end. I proceeded to connect this to my venerable Lamba linear power supply (+/- 12 V and 6 V), which I had adjusted down the 6 V output to 5.66 V. Connecting this to the KiwiSDR 2 similarly did not result in the BBG booting or any other visible activity. Once again, I stole the power supply from the old KiwiSDR to verify that the KiwiSDR 2 would boot up with a known good power supply.

I'm wondering exactly what voltage range is tolerable for the KiwiSDR 2? 6 volts is probably legitimately too far out of spec (+ 20%), and 5.66 V is a bit more than 10% over. Does anyone know what the power supply voltage tolerance is?

73,

Larry, NM7A/VE6VQ

Comments

  • G8JNJG8JNJ

    I tend to set the supply voltage at the DC connector, with the KiWi powered and running at 5.4v.

    This gives 5v at the internal header due to various voltage drops.

    As a result, I don't think 5.66v is likely to be outside the limits, but your issue may be more associated with the rise or ramp up time of the power supply itself, or the way it responds to a load being initially connected.

    An old trick to reduce the voltage is to place a silicon power diode in series with the +ve DC supply. Depending on the diode, and the current being drawn, this could introduce anything from typically 0.6 to 1.2v voltage drop.

    Regards,

    Martin

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