CW Filter for my FT-857D

Last year I decided that I wanted to learn and use CW. To that end, I enrolled and completed the CW Academy Level 1 class with the CW Ops group ( I have 2 CW QSO’s under my belt and I need to get on the air and make some more. Ion preparation for that, I decided to get the 500Hz CW Filter to add to my FT-857D. The radio has two slots for optional filters. Looking online, it seems the filters for the FT-857D are getting harder to find. I found one on INRAD’s web site and ordered one. It came a few days later and sat on my desk for a couple days. being Saturday and getting some things done, I decided to install it. I found it’s really very easy to install this filter.

To start with, there are 7 screws that hold on the top cover of the radio. 2 on each side and 3 on the top. The labels are simply my way of remember where things go in the back of the radio while it’s in my portable rack.

After removing the cover the locations for the filters are in the back left corner, as shown in the lower left portion of the photo below.

An up close look.

The filter is pretty easy to orient. There are 3 pins on one and and 4 on the other so it’s hard to get it backwards. There was also a reminder from INRAD that the circuit board went down and the label faces up. Here is after the installation which is simply pressed in.

After the installation, I wanted to make sure it was recognized by the radio so I powered it in and looked at the filter menu option and the 500Hz filter showed up as option B.

Now all I have to do is get on the air! When I do that, I will try to remember to make a video demonstrating how the filter affects reception of CW signals.

If you have a FT-857(D) and would like a CW filter for it, you might put this project on your list. I can imagine a day when these filters are really hard to find!


Wayne Patton, K5UNX, is a regular contributor to and writes from Arkansas, USA. Contact him at [email protected].

5 Responses to “CW Filter for my FT-857D”

  • Mark GØNMY:

    Hi Wayne,
    nice write up, you will notice a vast difference with the filter installed. when you are learning CW and get live on, air one of the hardest things to do is to filter out all the other Morse signals that appear on a busy band. You can do it but it does become tiring, well it does with me.
    Another option for a narrow CW filter is the SotaBeams digital filter which can be used on any radio. Check out Richards web site

    I use mine all the time now check out my blog

    Hope to work you on the bands 73 Mark GØNMY

  • Karl N7DMA:

    Welcome to the wonderful world of CW, Wayne! I also have and love my FT-857D (CW filter from W4RT).

    I’m sure you’ve heard it before, and if not…

    Join SKCC! Wonderful group of CW ops, and all are willing to match your speed.

    Get on the air, and enjoy your new skill!

  • Mike VE3WDM:

    Good morning Wayne, very nice rig the 857 I had one some years ago and I like when it was in the car I only had the remote head part in the cab, the rest of the radio was in the trunk. Inrad make a great filter I have 4 of them in my Elecraft K3. Once you get on the air making CW contacts it will be interesting to see your video.

  • Joe, K8JP/V31JP:

    I had an FT-857D and loved it. I had both the 300 & 500 Hz. filters. I worked a lot of mobile CW with it up here & in Belize. Sweet rig.

  • Gary Mayfield kk0sd:


    Does the transmit signal also go through the optional filter? The 857 is a great radio, but in a multi-radio environment like Field Day it transmits a lot of junk along with the desired signal. It is within legal specs, but could be much cleaner. I was wondering if the filter would help tame that issue as well?

    Gary kk0sd

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