[Elecraft] [K2] Low sensitivity with variable-bandwidth filter

[Bill Coleman]

I own a set of Rework Eliminator modules, so that should be easy.

I just have to find them….

> On Jun 11, 2019, at 3:09 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> Bill,
> 
> First try removing the KSB2 - put bent wire jumpers between pins 1 and 3 of J9 and J10.  Then see if you get a good response in CW.
> 
> Oh BTW, make sure the CW filters are centered at your sidetone pitch first - use an audio spectrum analyzer and if you have one, a broadband noise generator (if not, use band noise, but make sure there are on signals on the band segement used).
> 
> If the CW filters work OK with the KSB2 removed, the troubleshooting should start with the switching diodes on the KSB2 option.
> 
> 73,
> Don W3FPR
> 
> On 6/11/2019 2:53 PM, Bill Coleman wrote:
>> OK, I have a K2/100 w/ KAT100 that may have recently suffered from a static discharge event. I had to replace D16 & D17 in the KPA100, and I’m likely to do the same to the SWR bridge diodes in the KAT100 (since I can’t get the bridge to null properly).
>> The other thing I noticed is that the receiver sensitivity is substantially lower when using the CW filter. Using OP1, it seems to receive normally. I have three filters for CW 1.0, 0.4 and 0.16. When switching to 1.0 from OP1, signal levels drop by about 2-3 bars on the S-meter.
>> Anything in particular I should troubleshoot?

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Web: http://boringhamradiopart.blogspot.com
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901