[Elecraft] K3 Voltage drop

[Ron D'Eau Claire]

2.8V at 22.5 amps is 0.12 ohms total resistance in the cable, connectors,
etc. That's rather normal. 

That's why those cables between your 12V car battery and starter motor are
so big.

One approach used to maintaining voltage in spite of the unavoidable ohmic
losses is to run a third wire for the voltage regulator sense circuit to the
load. That way, the regulator is adjusting the voltage to maintain the set
value at the load, not at the output of the power supply. 

Be aware that if anything interrupted that connection, the power supply
would go to maximum voltage with serious consequences to the rig and any
other equipment connected at the far end. Also, a voltage sense circuit can
be rather sensitive to RF pickup which may cause the circuit to increase or
decrease the voltage. 

73, Ron AC7AC

-----Original Message-----



This really got me curious.  I was in the NAQP RTTY Contest.....and decided
to 
look at the voltage on my K3.  I checked the meter on the RM-35A, but those 
meters are not very good.  The volt meter says 14.5 volts.  NaH!    So, I
went 
to the K3 internal meters and got the following

100 watts out
22.5 amps
11 volts

13.8 volts key up.....

11 volts seems low to me.  So, I might have to do some checking out as well.

Lee
k0WA