[Elecraft] Filter Crystals

[Dave Gingrich K9DC]

At 19:04 12/16/2002 -0500, Brent Sutphin wrote:
>I have K2 # 2571.  I am one of those people who want my rig to work as 
>well as possible.  I am having trouble with the decision whether or not to 
>replace my filter crystals.  The filters are set up for a pass band of 
>1.5khz, 700hz, 400hz and 100hz.  Here is the symptom I would be trying to 
>eliminate. I loose 10-12db of signal strength when I switch to the narrow 
>100hz filter.  Is this normal?  I set my filters using Spectrogram and the 
>signal loss was measured with this software.  Any help would be appreciated.

I to was one that waffled on the crystal replacement for my K2 (S/N 
2211)  Mainly because I thought my rig sounded pretty good, and the filter 
traces, though humped somewhat, were not as bad as the examples.

BUT, this weekend, I did the BFO mod, and the 14 filter crystals.  What an 
enormous difference. The filter is as flat as a table on top, and with just 
a slight adjustment of L34, is identical for LSB and USB.

Unless you can confirm that your K2 was shipped with a matched set of 14, I 
would highly recommend the mod.  I also bought the parts kit for older 2nd 
filter mod (the one that switches in and out on rcv to xmt). Completely 
unnecessary with the new crystal set.

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Dave Gingrich, K9DC - Indianapolis, Indiana  USA
K2 #2211, K1 #931, QRP-L #2376, ARS #1109,
FPQRP #389, IRLP 4730,  k9dc.ampr.org
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