Don and Bert, Thanks for inputs from both. All measurement was done without the filter board. Petr ----- 73 - Petr, OK1RP "Apple & Elecraft freak" B:http://ok1rp.blogspot.com MeWe: https://bit.ly/2HGPoDx MeWe: https://bit.ly/2FmwvDt -- Sent from: http://elecraft.365791.n2.nabble.com/