If you already have one of these great little radios and use it mainly for CW as I do then it's worth considering fitting the CW Filter (300Hz) - I used it for some while without - but what a difference it makes WITH.
There have been articles published elsewhere but I did a post on it during January Last year and since found it had quite a few "Hits" so it was a popular viewing and I always intended to have another go at it, (never did) ;-( so since I have been doing some re-organizing on this page thought it prudent to put it up again  here.


This is the W4RT version - Collins Mechanical Filter
Start off by removing the Top Cover to expose the filter board and locate and match up the correct pins.


 The Filter sits in position on the two sets of pins to the front of the main board

This is how it looks in position, it's a push fit (Don't Force) 
Now all that is required is to go into the main menu number #38 where it should say OP FILTER, and just above it should read the word OFF, rotate the MAIN dial to read CW.
Press the Function button to exit the menu - then quickly press it again to go into the quick functions and rotate the selector knob until you reach IPO ATT NAR push the NAR button to engage it and it should now switch into cw narrow if it isn't already - if you want to switch between the two press NAR again - All straight forward, this is a very useful and simple modification and  what difference.
If your anywhere near serious about using cw fit one - it's worth it - one note - when you've fitted it, I recall when you change the modes and pass through the SSB mode it changes its tone I think but dont worry its normal.  It worked for me.