[INRAD] AM and IC-775 with Inrad roofingfilter

[Anders Janis SM4RNA]

Hi all!

I have installed the roofing filter in my IC-775. Before instalation I was worried that I would loose fidelity on AM. I am not a DXer on AM. I listen mainly to music on MW. After instalation I find the audio to better, not worse. It seems that the roofing filter has the bandwith that I want. Less signals from the stations on both sides makes the audio clearer. And as I wrote, the fidelity is the same. I have the optional FL-102 6kHz filter in the 9MHz MF and the two 15 and 6 kHz murata filters in the 455kHz MF is changed to 8 and 6kHz Kiwa filters.

Wonder if anyone else has eny experiences with the AM and the Inrad roofing filter? Have I been lucky and gor the BW I wanted?

I have ofcourse tested it on SSB and som on CW, but propagation has not been good so signals has not been to strong and there has not been to many stations on. However I find the receiver to steep slightly steeper about 3 kHz away from a strong station. This is not measured, just my impression.

I find the difference with and without roofingfilter to be greatest on AM. This surprizes me and the reason for writing this. The rest of the info is just a bonus. ;)

As I am already writhing I can just as well say something about the instalation. Most hams I know can install this roofing filter but not all. You have to remove several cables and a PCB and both the PS and the PA. If you know that you are not that handy ask a friend for help. It is easy to by mistake unplug some of the cables for instance the flat cable originating from inside the PA. Also Icom has put things together with a lot och screws and as the radio is heavy it becomes more or less a wrestling match to do the installation.

My conclution is that it is worth the wrestling, but if you are unsure, let a friend help you.

Thats about it!

73 de Anders SM4RNA