In my Icom 775 I currently have Icom 500 Hz filters in the 455 KHz and 9 MHz IFs. I have a chance to pick up an Inrad 250 Hz filter for the 455 KHz IF at a reasonable price. My question is has anyone used this Inrad filter (Inrad # 122) on RTTY and if so your opinion please. TU & 73 W0ETC