I only partially answered the question about when each wattmeter is used.
If the KAT100 is connected to a QRP K2 (KPA100 physically removed)
through a KIO2, then the KAT100 wattmeter will be used for power control
and SWR display in the K2 display.
As long as the KPA100 is physically connected, its wattmeter is used for
power control and also display of SWR on the K2.
73,
Don W3FPR
--------------------------------------------------------------------------------------------------------------------
Bill,
Both wattmeters (KPA100 and KAT100) are in-line at the same time. With
the KPA100 installed the KAT100 wattmeter is only used to calculate the
SWR and use that value to light the SWR bargraph. But otherwise they are
electrically equal.
Why the KPA100 diodes get zapped while the KAT100 ones are often
unscathed is a question I do not have an answer for - it may have
something to do with the physical placement of the toroid and the
diodes. The KAT100 has a greater groundplane area around the toroid and
diodes, and I believe that has something to do with it.
I would suggest that you do something like putting a non-inductive
resistor from the KPA100 SO-239 jack to ground to bleed off residual
static. I have used 3 watt 47k resistors successfully for that purpose.
While you are at it, put one across each ANT jack in the KAT100 as well
- if you have the KAT100-1, you can easily solder them on the bottom of
the board - with the KAT100-2, it is not difficult to solder the
resistors directly across the SO-239 jacks.
73,
Don W3FPR
On 5/25/2019 1:24 PM, Bill Coleman wrote:
Don, I have one question.
This is the second time my K2/100 has completely toasted D16 and D17.
I also have a KAT100 connected at the same time, which has virtually
identical SWR bridge.
How is it that a static discharge can destroy D16 and D17, but the
diodes D1 and D2 in the KAT100 are unaffected?
With the K2/100 / KAT100 combo, at which time are each of the SWR
bridges used?
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