[Elecraft] Wire size for the ground on the KX2

[Fred Jensen]

Good to know!  My K2 no longer has the KPA100, but I still have the BNC 
Tee on the antenna.  K3 does as well. You can calculate the required 
resistor size [watts] with a little arithmetic.  I've used anything from 
about 56K to 220K, whatever I find in the junkbox.  When us "old guys" 
fried the two ICOM's, the noise was just very mild "bacon frying" and 
barely noticeable on the baseline of the panadapter, certainly nothing 
to provoke alarm.

Important to note though that this is different protection for the input 
than a gas discharge tube or other lightning arrestor device.  They may 
protect against major voltage surges but are otherwise open circuits.  
And, enough of a surge that fires the device may still get through to 
cook the front end components.

73,

Fred ("Skip") K6DGW
Sparks NV USA
Washoe County DM09dn

On 6/17/2017 5:18 PM, Don Wilhelm wrote:
> Skip,
>
> Yes, I believe that later Elecraft products do have a static bleed or 
> other static prevention across the antenna connections.
>
> BUT for K2 owners, that is not the case.  The original KPA100 design 
> had a 100uH RF Choke across the antenna terminals for just that 
> purpose, but the latest KPA100 upgrade (to reduce the chance of an 
> oscillation of about 8MHz when on 40 meters) the choke was removed 
> because it coupled with the base K2 causing the oscillation.
>
> For those K2 that I repair that have damaged wattmeter diodes in the 
> KPA100, I have been installing a non-reactive 47k 2 watt resistor 
> across the SO-239 jack, and also across the antenna jacks in the 
> KAT100 (I put them on the bottom of the board, it is easier than 
> soldering directly to the jacks).