When I assembled R909 radio, I found several improved issues from R80 V7. As the R909 radio circuit is improved from R80 V7's, It is useful for who would like to improve R80 V7 performance. (R909 is the Arduino based FM/AM radio from JasonKit. )www.tindie.com R909ブロックダイヤグラム 1. Countermeasure against…