K2 Bandpass Filter Mystery

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K2 Bandpass Filter Mystery

Beth Wenzel
Hi guys,

My K2 works perfectly on 80 40 and 30 meters (12 plus watts on all bands), however as I go higher in frequency the power output falls off until I only get about a watt out on 10 meters.

I've check the relays to insure two filters weren't in line at once, checked all of the component values etc. Finally with an 0-scope in hand I've found that there is significant attenuation at the center cap in each of the higher filters.

Bridging the 10 meter filter with a jumper netted about 7 watts.

Putting a 10pf cap in parallel with C22 has boosted the 20 meter output to 10 watts, putting a  33pf cap  in place  of C46  has decreased the attenuation to allow about 4 watts out on 10m (up from about 0.9).

The inductors do peak at about the center of their travel, the four cans for the higher frequencies are the matt silver type with the tiny flathead screw top, and match the description in the manual.

Any ideas as to whats up? Seems very weird.

73 Mark AB9LZ.  
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