FT-857 and CW operating

I have very limited experience operating with morse and have a much loved and ancient FT 857 that I’d like to use for morse occasionally.

When purchased, morse seemed like a pipe dream and I therefore didn’t purchase a CW filter and now I’m pretty sure these are “unobtanium”.

Given it’s hard enough for me to decode one morse signal, potentially having a gaggle of them in my 2.8Khz passband will most like heavily distract me.

What suggestions does any one have in making my ancient 857, morse usable for this newbie?


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Hey Paul, it’s been really great working you on CW… so glad you took the plunge!!

The filters are hard to find, but not impossible. Check QRZ swap forum, they do pop up from time to time. Another option that works but not as good as the proper filter would be the various DSP audio filter boards that are available. I installed one of these in an FT-817 for a friend once and it was okay. The ACG pumping in the presence of strong signals nearby was not so nice.



Hi Paul

Secondhand is your only option it seems. There was a firm called FT used to make narrow Xtal filters for Yaesu and other makes of transceivers that were highly regarded. I don’t know if they are still in business - worth looking.

I recall that some of the Yaesu xtal filters part numbers can be a little confusing so you may find identical filters with different part numbers, so try and find out which ones to look for when you are trawling t’internet.

You could try a wanted ad on the G3CWI Fleamarket website. Good luck in finding one - a narrow CW filter is essential I would say on the FT-857.

73 and Happy New Year

Phil G4OBK


Hi Paul,
Have you looked at one of these boards as an option:

73 Ed.


Theres one for sale on Ebay but $334??? yeeesh

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You can also build one…


Yes, they are. Mostly because Collins stopped making the crystal filters that Yaesu and others used.

Apart from Yaesu a company called International Radio make a clone. Note that the filter you need is also used in several other radios made by Yaesu see:

73 Colin

Hi Paul,

Nice to see this post bcse I as complete newbie of CW started my activations with FT-857 and haevy borrowed paddle key - I was not sure at tha time CW is for me or not …

I want to assure you: you do not need anything to adjust default FT-857 for SOTA activation.

Just be brave, you will get it with no problem bcse always some operators are very good readable.

You can do it - you have Polish ancestors :stuck_out_tongue_winking_eye: :grin: :exclamation:

73, Jarek

EDIT: for good start pls try to call by yourself some S2S that you will copy - it was my start to work Igor @OM3CUG - my first SOTA CW QSO was S2S with him :wink:

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Hi Paul, HNY
I always advise those who are looking for filters to use to the limit the filters that they already have incorporated by nature: Ears and brain.
I’ve been running a FT857 without filters for 7 years now and I think I do quite well when I operate at 7mhz (Imagine that 7mhz in JA is pandemonium!!!) I can understand you if you are going to be operating for hours and hours, but as far as SOTA is concerned, I never considered filters as something essential.

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There are people who can cope without a narrow CW filter. I’m not one of them. It maybe that you can train yourself to cope but I bought a filter when I got into CW and they were available. Well I’ve bought a filter for all my HF rigs.

My memory of the filters for the 8x7 family is hazy now. They all used Collins Mechanical filters. Yaesu ones for 300 and 500Hz used different Collins filters to the InRad ((International Radio) ones. InRad had sharper skirts ISTR.

However, your only course is to scour the second hand sites (eBay et. al) and be prepared to pay. In the UK I’ve seen them go for under £100 in 2023 ( I missed the chance to buy for £100 and sell for £125!) But £125-150 is the price now.

Don’t be be afraid to buy an 817 with filter, strip the filter for your 857 and sell on the 817. Having both 500Hz and 300Hz, I would go for the 300Hz every single time. To me it sounds better. YMMV

Just a thought… amongst your vast trove of toys don’t you have a K2 with a 100W PA you could use instead?

And as Josh says it’s great to see you working CW and especially wanting to invest (that’s what it is) in a CW filter for your rig.

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The FT-857D variant has an audio DSP board with bandpass filters, the default CW bandwidth is 240 Hz but it goes down to 60Hz. I have been told that the DSP board is/was available for retrofitting on the earlier FT-857. The disadvantage as mentioned in an earlier post is pumping of the AGC if there is a strong signal in the IF passband. This can be controled to some extent by reverting to the older method of managing the receiver by switching off the AGC, setting the AF gain to max and using the RF gain as an AF gain. This generally works for me.


Thanks all for the feedback.

@G8ADD and @WU7H I like the idea of mastering the DSP filter (I have the D version) and seeing what that does for me. Maybe on 10m it will work just fine.

@MM0FMF The Man Cave does sometimes resemble Aladdin’s Cave and you are right that I have a K2/100 (even more treasured than the 857D). While I think the K2/100 a greater (better than 857D) its just a tad too large/bulky/heavy to lug on anything but a “drive up”. The 857D is at the high end of what I can imagine lugging over miles and up 1,000s of feet. Buying a used 817 and selling it on minus the filter is a great suggestion.

@JP3PPL and @SP9MA I’ll give it a try minus the mechanical filter. Not all “wet matter” filters are created equal but I’ll see what I can manage especially given 10m is “wide” band.

@K9EZ and @G8TMV - Those prices are outrageous!!

@DD5LP I’ll look at these and see how much work is required to install and effectively operate. On a side note the “after market” but official DSP module on the K2 seems so clunky to use but maybe with practice the SOTABeams will be easy to use.

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It works brilliantly but I’m afraid to use mine in case I can’t get it back to normal. I have to keep all the K2 manuals for my K2 options on my phone “just in case”!


I totally agree with this. I had the “stock” Collins 500Hz filter fitted to my 857 when I bought it. After a few months I added a W4RT 300Hz filter as I had in my 817 and I never used the 500Hz afterwards. I sold both filters and the rig separately, though I kept the 300Hz filter for a while as a spare for my 817… as if I would need a spare. :grinning:

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I agree with the comments above re 300Hz filter for CW.

As a CW-only operator 18 years ago [I’ve relaxed a bit since then] I bought a Yaesu YF-122CN CW narrow (mechanical) filter with my FT857. It’s rather good and better - being an I.F. filter - at coping with strong adjacent-frequency signals than, say, the DSP-based A.F. one in the FT857. Although the latter has a nicer tone to it and - as others have said - has 240, 120 and 60Hz options.

Apparently [according to K6XX] a mechanical filter had poorer strong signal selectivity but a cleaner in-passband tone than an equivalent crystal filter but its ‘skirts’ are not as good [No jokes please].

It’s probably invidious to compare the performance of the 1990s-designed FT817/FT857 or their filters with modern software-defined radios (like my KX2).

FT-857 is good for CW operators. You can create a CW memory keying for A, B and C buttons!

Thanks for the tip.

Agree; chasing on big-rig at home, often use 50KHz filter.


I’ve lost track of the bottom line of this conversation, Paul. did you ever
find a CW filter? And if not, does the FT857 take the same filter as an FT-847?
If so, I think I have the original 500 Hz filter from my FT847 hiding out in the shed.
If it will work and I can find it I’ll make you a deal you can’t refuse on it.
John, k6YK

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