[Elecraft] Remote Antenna Switches and K2 Questions

[Don Wilhelm]

Ted,

Yes, you have that right.
Capacitors or diodes across the relays would be a good thing to swallow 
the voltage kick when the relay is de-energized.

If your DMM is showing voltages in excess of 13 volts, then the peak 
voltages will be much higher.
The diodes or capacitors would have to go into the remote box across the 
relay coils.  If diodes are used, observe the polarity carefully - the 
cathode must go the the side of the relay with the more positive voltage 
- in other words for those relays driven by negative voltages, the 
cathode goes to the side with the negative voltage closer to zero volts.
Diodes will do a better job than capacitors.  If you use capacitors, I 
would suggest 0.1uF although 0.01uF may be sufficient - it all depends 
on the inductance and resistance of the relay coil.

73,
Don W3FPR

On 3/26/2016 7:48 PM, Dauer, Edward wrote:
> Don Wilhelm pointed out
> that because the LPF in the K2 is grounded on one side the presence of DC
> itself wouldn’t be a problem, but that rapid changes in any voltage
> getting into the RF input side could be. (Do I have that right, Don?)