Joel,
I do not have a v6 uBitx, so do not have direct experience with that specific kit.? I do have both v4 and v5 boards, and all do run the regulator hot, especially if I use a 13.8 volt "big rig" power supply.? What I did to tame the temperature was to add a dropping resistor on the 12vdc (actually 13.8) in series with the regulator.? two 2 ohm 2 watt resistors in series.? This drops the voltage across the resistor so that the regulator does not have to disipate the heat.? This value can be up to about 47 Ohms depending on how much current you are planing to use for add on things.
Others have added a 7809 9vdc regulator in place of the resistor.? This spreads the load across the two devices and works well if the input voltage is always above 12vdc.? You would need to go to a buck/boost regulator if you are going to power from battery power if you want to rung the batteries to almost fully drained.
Most v3, v4 and v5 boards have been running with the stock circuit and no heatsink.? Adding the graphics display increased the current need, which is why I believe that HF Signals added the heatsink.
Bottom line of the above is that the heat dissipation at 12 votls is within the spec of the device, and I would not be worried.? ?If you are running over 12vdc in, then putting dropping diodes in series with the supply to the main board, NOT the power amp, would be my suggestion.? The finals can take the higher voltage and produce more power out, at the risk of overheating the finals.
Above should be verified before implementation
73
Evan
AC9TU
