So, if you turn the KPA100 off via the menu, the KPA100 SWR bridge is still used in any case?
I’ll plan to add 50-100 kOhm resistors across the output, as you suggested. I’m also going to re-do the calibration of both SWR meters, just make sure no damage was done to the KAT100. > On May 25, 2019, at 1:52 PM, Don Wilhelm <donw...@embarqmail.com> wrote: > > 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? >> >> > > Bill Coleman, AA4LR, PP-ASEL Mail: aa...@arrl.net Web: http://boringhamradiopart.blogspot.com Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
