It is no secret that the filtering for CW in the FT-818 is a weak point. It is also common knowledge that the Collins filters for this radio are extremely hard to find and, if found, are expensive. Fear not, for solutions still exist for those wanting an improved listening experience for this radio.
To this end, I built a SOTABeams LaserBeam-Dual DSP filter. This filter comes in two formats, for either internal integration or external add-on, and in three filter configurations, CW wide and narrow, SSB wide and narrow, and SSB wide/CW narrow.
SOTABeams LaserBeam Dual with BoxaDual enclosure on SotaBeams.co.uk
SOTABeams LaserBeam Dual filters on DX Engineering
SOTABeams LaserBeam Boxa-Dual enclosure on DX Engineering
Links are provided for convenience only. I do not gain any commission from these.
Honestly, I like building kits, but performing non-essential invasive surgery on my FT-818 makes me nervous, so I opted for the externally mounted Boxa-Dual format in the CW wide and narrow configuration.
The kit comes in two parts: the filter board itself and the enclosure.
The filter board, the square PCB component with a round, green sticker on it, consists mainly of the SMD mount signal processor and header pins. This part is made to be integrated within the FT-818 but I chose to mount it into an external enclosure.
The rest of the components go to the interface enclosure which comes with header jacks for receiving the filter board, 3.5mm audio in and out jacks, 2.1mm barrel DC power jack, volume pot and knob, an audio amplifier IC, a switch for choosing between narrow and wide filter modes, indicator LEDs, and various resistors, capacitors, and diodes to tie everything together.
It is easy to build, with all SMD components pre-mounted and generous spacing for the remaining through hole pieces. Once all soldered up, the enclosure and end plates are well made and look slick. In all, I believe it took me less than an hour to put together.
Most importantly, it works great! The signal processing is just what I wanted, both the wide and narrow CW filters. The narrow CW filter is tight, around 300 Hz, and eliminates adjacent signals and QRM really well. This comes in handy during contests. The wide CW filter is useful for opening up the audio for scanning the bands for other stations calling CQ.
I liked it so much that I decided to build another one for SSB as well. It also works well, but it is less important for this mode than it is for CW. Don’t get me wrong, I prefer to operate with the SSB filter in line with my audio.
In the end, I only have two complaints, if you can call them that. For starters, it’s a shame that the filter is not offered in the CW narrow/SSB narrow configuration. For me, that would have been the best of both worlds instead of the CW narrow/SSB wide filter offering. Second, I wish that the enclosure were black anodized aluminum (much like the QMX cases) instead of raw aluminum with faint gold colored plastic end plates. Like I said, these are minor points.
Now that I have these filters, I don’t like operating the radio without them. They make a world of difference and if you’re wishing for tighter audio on your FT-817 or FT-818, the SOTABeams LaserBeam Dual DSP filters in the Boxa-Dual enclosure are well worth the investment.
Want to hear what the filter sounds like? Here’s a short and sweet demonstration by Nick, ON4MGY.
Amateur Radio Station WB0ISG 