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Posted by Loren on 4/13/2005, 2:31 pm What am I forgetting to check here? Additional question: Thanks. >
208.57.38.52
I have an SB201 (like the SB200 w/o 10M) that has a problem on 80M. The output is down about 50% from what I get on the other bands and the meter lamp is visibly brighter while in TX with 100W CW input. To me it looks like RF is getting into the cathode circuit but I'm not sure how to nail it. All tests made into Cantenna.
I have checked the following:
>Input and output SWR - ok
>caps switched in for 80M and switch contacts - ok
>0.02uf 1kv caps in input and filement - replaced
>Plate voltage - ok
>Plate current - lower than on other bands
>Grid current - lower than on other bands
>plate and cathode chokes visually inspected - ok
In the input circuit there is a board between the input networks and the cathode circuits that I don't see in the schematic. The board is covered with an aluminum shell rivited in place with a label "do not break seal". I am assuming this was added to preven 11M use. Is this correct and has anyone out there removed it for 10M work?
AD6ZJ, Loren
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