One-Board Filter
Another Great Product fromW4RT Electronics

Dear Fellow FT-817 and FT-817ND Enthusiasts,

Thank you for your interest in the W4RT Electronics "One-Board Filter" (OBF). The OBF affords you the opportunity to have both the Collins CW and SSB mechanical filters available in your FT-817 or FT-817ND together! This is the option that many, many FT-817 owners have requested. In the rest of this document, FT-817 should be taken to means FT-817ND as well.

The OBF utilizes Collins Mechanical Filters that are the same as used in the optional Yaesu filters for the FT-817. The bandwidth of the 7-pole CW filter is 500 Hz and the 10-pole SSB filter is 2.3 kHz. The special printed circuit board for the OBF, designed by W4RT Electronics, utilizes the same technology and PCB manufacturer it has used for its Government contracts. The OBF contains components necessary for proper termination of the respective filters in accordance with Collins specifications. W4RT Electronics gave careful attention to filter termination in order to achieve excellent shape factor, flat passband, low-ripple, etc. performance afforded by the Collins filters.

So how does the OBF fit into the FT-817 and how do you operate it? The OBF fits into the space where the Optional Filter is normally located except that the OBF requires all of the space in this optional filter area. The OBF SSB filter functionally replaces the 2.2 kHz MuRata ceramic filter contained in the FT-817. The installation of the OBF requires two basic steps. First, the MuRata ceramic filter is physically removed from the radio. Second, the OBF is mounted on the seven pins for the Optional Filter and wires from the new Collins SSB filter are connected to the main FT-817 PCB in place of the former MuRata filter. The OBF is soldered to the Optional Filter pins because this is a permanent installation and the long-term reliability of this approach is greater than using sockets. The following photograph shows an installed One-Board Filter.

After installation, Menu #38 is set to CW (and never needs to be changed again). You never have to select the SSB filter because it is always in the circuit anytime the former MuRata filter was selected. To select the CW filter, you simply press the NAR Key (Function Row 7, Key C) when desired (and you are in a valid Mode).

The One-Board Filter is now available for installation by FT-817 owners that have adequate skill and equipment to work with SMT components. The One-Board Filter can also be installed by W4RT Electronics, which requires that you ship your FT-817 to W4RT Electronics. The installation will take place and the radio will be shipped typically within one business day of receipt of your FT-817.

As you likely know, the suggested retail price of the Yaesu CW and SSB filters are each $170 and the equivalent filters from International Radio (INRAD) are $125 and $145, respectively. The One-Board Filter for W4RT Electronics is priced at $269 installed and $239 for user installed. Frankly, this is a rather good value.

In the October 2001, issue of QRP Quarterly from the QRP-ARCI, Greg Buchwald K9QI published a review article that discussed the W4RT Electronics filters and specifically the OBF. The following are excerpts from this article (by permission of K9QI and the Editor of QRP Quarterly). [If you are not a member of QRP-ARCI, then see for information about the organization and joining. Just $15 per year and the QRP Quarterly is included!]

    • On comparing the MuRata ceramic filter that is standard in the FT-817 with the Collins SSB filter, he states "The Collins filters are 325 Hz narrower at this point, a much better shape factor providing better attenuation of unwanted signals. The other obvious difference is the flat response of the filter. The SSB filter has less than 1dB of ripple throughout the passband. On the transmit side, this insures that higher frequency components, those generated by consonants, will be articulated at the distant receiving station. For those hams operating QRP PSK-31, it means a more uniform relative signal strength (and therefore flatter MDS) as you tune across the waterfall display trying to pick the station which you wish to converse with. "

    • On the matter of the benefits of using the Collins SSB filter, he states "By adding the W4RT filter board, I not only got the benefit of the filter response for SSB work, but I also gained the equivalent of cranking up my power by 2dB without changing my true PEP one bit. That’s like running 8 watts rather than the 5 the rig actually puts out. Sure, that doesn't seem like much, but in some situations, every bit helps. Plus, I could only estimate that the increased clarity of the signal, due to the sharper skirts and the more uniform phase delay response, added the equivalent of another 3dB or so energy."

    • On commenting about the installation of the One-Board Filter, he stated "Are there any down sides to the conversion? The answer is a resounding NO! "

    • On potential concerns that the One-Board Filter might harm the performance of the FT-817, he stated "Furthermore, I saw no change in the sensitivity of the receiver. In fact, the MDS on CW remained at -136dBm exactly where I had measured it with the stock ceramic filter plus the optional Collins mechanical filter from Yaesu. There is no need to be concerned over any loss of performance; my findings have indicated that there is a considerable increase in performance over the stock radio."

    • Overall, he stated "Bottom line, if I didn't like the product I would have printed that as well. But, I can't praise it high enough. This is exactly what the rig needed!"

Frequently Asked Questions:

    · Who is responsible for packing, insuring, and shipping the radio to W4RT Electronics? The radio's owner. You are encouraged to pack the radio very well and to insure it appropriately. A tracking number is also strongly suggested. Use good quality shipping materials. (The original factory carton packed in a strong outer box is suggested.)

    · Should the radio be shipped with the batteries or battery pack installed? No, unless it is the W4RT OPP.

    · Should the radio be shipped with the Optional Yaesu or INRAD filter installed? It is okay to leave it installed.

    · How is the radio shipped back after the OBF installation? The return shipment will be by UPS Ground and insured for $1000. (US only.)

    · Is shipping included in the price? No. The charge will be $12.50. (US only.)

    · Will I know when my radio is shipped? Yes, you will be emailed the date of shipment and the tracking number.

    · Do I just send my radio after I place the order for the OBF? No, please wait till we notify you we would like to receive your radio. Typically, there is no delay. Our intent is to have your radio away from you the minimal time practicable.

    · I don't live in the USA. Can I still have the OBF installed in my radio? Best to purchase the user installed version of the OBF. Some non-US hams had the installation performed during their visit to the US. W4RT Electronics will attempt to work with you.

    · Does the OBF interfere with the installation of the optional TCXO? No.

    · I have the FT-817ND. Does the OBF install the same as in the FT-817? Maybe, but some of the FT-817ND units have two very-small SMT resistors placed in the filter circuit where SMT capacitors were used before. If your FT-817ND has the resistors, they need to be preplaced with the proper capacitors. This requires proper SMT skill and equipment. If you don't have both, then we strongly urge you to have W4RT Electronics perform the installation for you. Please see the manual.

    · Does the SSB filter really improve the performance of the FT-817 on SSB? Yes, in our opinion. This is based upon both laboratory and on-the-air tests. The passband is much better defined and is very flat. Talk power and speech clarity are improved. On receive, you will not hear significant improvement with the built-in speaker; however, if you use a higher quality speaker or good headphones, the difference will be obvious.

    · Does the OBF affect the use of an external DSP like the HEAR IT, bhi, or ClearSpeech units? No, except that the results will likely be better due to the higher quality audio from the receiver.

    · Are there any adjustment to the OBF? No and yes. There are none on the OBF, but the FT-817 does provide the control of the carrier insertion point on both transmit and receive (see Menu #54-57). These can be adjusted for your voice characteristics (to maximize talk power) and best listening.

    · I already own the Yaesu or INRAD CW and/or SSB filter(s). What do I do with it (them)? We suggest that you try to sell it (them) to a friend, on,,, etc. Alternatively, we will accept your filter, test it, remove it from its mounting, and use it in your OBF. You will be given a $50 credit for each filter. Contact W4RT for details.

    · Can I have a 300-Hz Collins Mechanical Filter? Yes you can. The 300 Hz is generally selected by those working contests and PSK. For PSK, the 300 Hz and the 2300 Hz are a good pair since the transmit uses the 2300 Hz filter. The stock filter rolls off from center frequency and means you decrease ouput power as you operate away from the band center. The Collins 2300 Hz fillter is very flat and resolves the aforementioned problem.

    · Why is the business called W4RT Electronics? Simple. W4RT is the call sign of our club station (Tornado Amateur Radio Club) in the parent company, the PanTechne Corporation.

    · Is W4RT Electronics now or has it ever been a part of RT Systems? No.

    · Can I call you on the telephone to discuss the OBF? No. We don't have an incoming customer telephone line. Please send question by email or fax. They are handled quickly.

Thank you for your interest in W4RT Electronics products; the entire W4RT Electronics Team sincerely appreciates your support. We are confident that you will find the OBF to be an outstanding addition to the FT-817 that will enhance your operating enjoyment for years to come.

72/73 de The W4RT Electronics Team