[Elecraft] K3 - How much supply voltage is too much?

[Ross Primrose N4RP]

On 5/10/2011 3:13 PM, Jim Brown wrote:
> If it were my radio, I would add one or two silicon diodes in series
> with the positive lead to reduce the voltage to about 14 volts. For a
> 10W K3, I'd guess that 5A diodes would be just fine.

I'd thought about that as a possibility. Heat could be an issue, 
especially if I want it to be easily portable, at 5A, that's about 
3.5W/diode assuming a 0.7V drop.

> If it's a laptop supply, I would also be concerned about RF noise that
> it might produce.

I'm concerned about it too, but the laptop supply is already in hand, 
and without a laptop, so it's worth a try. I know the old desktop PC 
supply I'm using now has broadband noise at 7.070-7.080, so maybe this 
one will be better (and definitely a lot smaller!).

73, Ross N4RP

-- 
FCC Section 97.313(a) “At all times, an amateur station must use the minimum transmitter power necessary to carry out the desired communications.”