QRPer.com readers know that I’m a big fan of the venerable Yaesu FT-817 and FT-818 series transceiver. So much so, I own two FT-817NDs–I purchased a second unit last year primarily for full duplex satellite work.
As I mentioned in a previous post, the one gotcha with the FT-817 and FT-818 is narrow CW filter availability. The YF-122C 500 Hz and YF-122CF 300 Hz Collins filter boards are no longer produced. Neither are the Inrad equivalents.
With the renaissance of CW we’re experiencing along with the growth of POTA, WWFF and SOTA, narrow CW filters for the FT-817/818 are very difficult to find and come at a premium when you do find them. I saw one sell recently for $250 US–over double what I paid two years ago.
In addition, this same filter not only fits the FT-817/818, but I believe it also fits the popular FT-857 and FT-897 series transceivers (please correct me if I’m wrong about this).
The Problem: I wanted another narrow CW filter
One of my FT-817NDs is loaded with a Collins 500 Hz mechanical filter that I purchased from my buddy Steve (WG0AT) nearly two years ago.
The second FT-817ND had a narrow Inrad 2 kHz SSB filter that came with the radio when I purchased it used (see image above). Initially, I had no intention of buying yet another narrow CW filter because I’d only planned to use the second unit for FM and SSB satellite work.
Then, during field day this year, I decided it might be fun to build a quick-to-deploy portable HF station with something like an Armoloq TPA-817 pack frame. That thought experiment made me realize that I should simply bite the bullet and get a narrow CW filter for the second FT-817ND.
I started searching in late June and was simply not willing to pay the price for the very few filters that have shown up on the the used market.
The Solution? Assemble one!
I owe QRPer reader, Petr (OK1RP), for this tip. Thank you, Petr!
The process of assembling your own narrow filter is actually quite simple and affordable. If you have even the most basic soldering skills, you’ll be able to manage this easy project. If interested, keep reading and I’ll show you how you can assemble your own…
Contact Artur (SP6AB) and ask to purchase one of his FT-817 filter boards
Artur makes these filter boards in small quantities and will configure them for the Collins 526-8693-010 500 Hz filter. This requires adapting boards he originally designed for a different Collins filter, so he must cut a trace and add a few extra components. Because of this, the lead time is typically one week.
Artur charges a very reasonable $10 US for the board and $5 US for shipment via registered letter from Poland. Artur does this as a service to his amateur radio community; he could obviously charge much more. What a great fellow.
I received my filter board within two weeks of it being shipped.
Contact Artur at the following email to confirm pricing and availability: [email protected]
Make sure to tell Artur the actual Collins filter part number you’ll be using so he can configure the board properly.
Purchase the Collins narrow CW filter
You are looking for the 7 pole Collins 526-8693-010 (AOR MF500) filter.
There are a number of eBay sellers offering these filters–most are located in Japan. Prices range from $103 – $160 US, but the majority are less than $125 US.
I purchased my 7 pole Collins 526-8693-010 (AOR MF500) from this seller and paid about $108 US shipped. Shop around, though, as there are many sellers offering this filter (double-check the part number prior to purchasing because eBay will often show results for similar part numbers). I chose this particular seller because they offered free expedited shipping and a 60 day return window. They also had 100% positive ratings. I received my filter via FedEx within 2 weeks of purchasing.
Finally, solder the filter to the circuit board and install it
This bit couldn’t be easier.
Since Artur essentially does all of the hard work on the board, all that is needed to mount the Collins filter to the board is to solder it in three spots.
The process will take a max of one minute once your soldering iron is hot!
Here’s how the filter should be oriented looking at the top of the board:
[Update: Artur has made a slight change to the filter board design. It’s still intuitive, but if you would like to see the new board, check out KM1NDY’s blog post and images and also photos by Steve (MW0SAW) at the bottom of this post.]
Finally, mount the new filter board in your Yaesu radio. This board simply slides onto pins inside the radio. Take your time to properly align the pins so that the filter boards sits properly.
Here’s the location in the FT-817ND:
Hook your antenna up to the radio and activate the narrow CW filter from the quick menu.
It was rewarding to hear the 500 Hz filter engage. I was lucky in that a CW contest was in progress, so could quickly hear the improved results using the narrow CW filter.
So pleased with the results!
Again, I’m most grateful to Petr for pointing out this affordable filter option and for Artur to offer his modified filter boards at such a reasonable price.
I paid a total of $123 which I feel is money very well spent and much, much less than the inflated prices we’re currently seeing for the Yaesu YF-122C on the used market.
Now I need to revisit the Armoloq TPA-817 pack frame idea.
Update: New filter board
As mentioned above, Artur made some slight modifications to his filter board design. If you’ve ordered one recently, it might not look identical to the ones in my photos. Steve (MW0SAW) kindly provided the photos below of his filter install. Thanks, Steve!
Thank you for reading this how-to article. I hope you found it useful.
Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support.
Thank you so very much!
Cheers & 72,
Thomas (VY2SW / K4SWL)