On Fri, Jun 29, 2018 at 7:17 PM, Mark M <junquemaile@...> wrote:
The issue discussed in the 'RFI from uBitx TX after AGC and other mods installed' thread appears to be caused by RF getting into the 12v supply and from there into the 5v supply that feeds the AGC board (the ND6T/K5BCQ kit). At least that appears to be the issue on mine. I thought I'd start another thread to talk about that.
I have the ubitx in a case from . The power comes in thru a plug in the rear panel at the right of the panel (looking at it from the front), thru a fuse and then thru three wires twisted together along the rear panel to the connector on the board at the far left. There's also a polarity protect diode across the supply. The power connector is right next to the antenna connector and the supply wires run past the final transistors and .
I'm running the ubitx on 13.8v from an Astron 20A power supply, The testing was done feeding a Heathkit Cantenna dummy load.
So, any suggestions on how to fix this would be appreciated. Don mentioned heavier supply wires and capacitor at the input. I thought I'd try re-routing the supply wires inside case to get them away from the RF section. Moving the power connector to the other end of the rear panel would make the run much shorter. Other than that, I don't know. RF hardware is not my forte (I'm mostly a software guy).
