Anil, thnaks a lot for pointing at your book! Great source. Not attempting to hijack this thread, but I glanced at book content through Google view in hope to find prescriptive formulas for printed board LPDA elements and boom calculation relative to gain/frequency range etc. etc., but couldn't find any. We do have a nice calculators for a "legacy" tube LP, but not for PCB based one. Any idea or reference to where to find one, step by step? So far it's being trial and fail for me and was heavily based on a few articles and limited references. I think I've got a good one by the end, but would like to make an exact calculations to clarify.