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).
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