Aviation Headset Connected to FT-897

Those among us who do both flying and ham radio have a dilemma: as a pilot we usually own a high grade aviation noise canceling headset that is generally of better quality than most headsets available in the ham radio market (I personally own a David Clark H10-13.4 headset … try to find a passive headset with similar robustness). However, all standards regarding plugs etc. are different and it looks like there is no commercial solution available to interface your aviation type headset with your ham radio gear – at least to the best of my knowledge.

So, in the best tradition of ham spirit, I decided to build an interface. Since I still use my headset for flying cutting off the plugs and replacing them with ham plugs wasn’t an option. First problem: where do you find the correct female connector? The phone part of a civil fixed wing aviation headset (caution: different standards for military, helicopter, and commercial airliner!) uses the standard 6,3mm headphone plug equivalent to your stereo headphone. The microphone, however, uses a 5,6 mm three pole plug. No chance to get them at your local electronics dealer. Fortunately there are a couple of aviation specialty mail oder stores than can help you out … for instance Friebe, Siebert, Büscher in Germany, or Aircraft Spruce in the US).

Plugs for the FT-897 are simple. Headphone plug is a standard 6,3mm phone jack (you can actually plug the Aviation Headset right in if you want to), the mic jack is a standard RJ-45 jack. Since I didn’t want to buy the necessary crimping equipment I just used a surplus network cable.

The interface is built in a small box containing the receiving sockets for the aviation headset, the cables to be connected to the transceiver (phone and mic, both ca. 1,5m long), a push-to-talk switch (PTT), and a jack to connect an additional external PTT switch. This way the interface box is very conveniently located in the middle between the headset and the transceiver which gives you additional room to move and enables you to overate the PTT switch holding the interface box in your hand. The following picture shows the overall configuration.

The circuit itself is simple and requires only a few standard parts to provide the microphone with the necessary power and to adjust the microphone output level.

Pin 3 provides via the 470 Ohm resistor the necessary power for the mic, the two 47uF capacitors remove the dc component for the audio input to pin 5.  The 1k poti / 6k8 Ohm combination allows for the necessary output level adjustment.  A 1nF capacitor removes any HF components that might end up in the system.  I decided to include the pin 3 (tip connector) of the headset mic plug that is used in aviation systems as PTT switch.  That enables me to use other aviation mics (e.g., handheld mics) with the same interface.  Since the aviation standard does not provide a different ground for PTT and MIC I had to connect pins 4 and 7 at the Yaesu Mic connector.

As you see, all components fit comfortably in a 100x50x25 mm box.

Before closing the box adjust the microphone output level using the built in ALC meter in the FT-897.  Fine tuning can be accomplished with the “SSB Mic Gain” menu in the FT-897  settings (menu no. 81).

My experiences with the configuration are extremely positive so far. My David Clark headset provides excellent noise cancellation abilities and the noise suppressing microphone works very nicely with my Yaesu rig.

Any further comments and tips are highly welcome.

Vy 73 de Jens, DJ2UM

35 thoughts on “Aviation Headset Connected to FT-897

  1. Dear Mr Jens,
    Can I have you email address? I need your help, if you can, for military headset w/microphonedynamic M-87/AIC. I would like to send you the pictures of my headset to understand if your circuit can help me to give power at that mic. I use a TS -2000 or TS-440.
    Thanks and ’73
    Alessandro

  2. I have a question with this circuit adapter.
    Have a Flightcom 40LX Headset + FT-897D . In FM the modulation is correct but in HF it´s impossible a lot of gain and noises.

    The schema is correct?
    Any suggestion?

    Thanks!

    • Hi, I would assume that you have to modify, i.e. lower, the NF level going to the transceiver. If the range of the trimmer doesn’t work you might want to change the resistor in line with the trimmer.
      Let me know if this works.
      Best regards – Jens

  3. Hello
    I have a TS2000 like Alessandro with an aircraft headset. Did you found a solution ?
    Thank you in advance
    Best regards – 73

  4. Dear Mr Jens,
    I have the same transceiver than Alexandro. I try to create your solution but it doesn’t works correctly.
    Did you found a solution for Alexandro?
    Best 73
    Thierry

  5. Sehr geehrter OM Moeller,
    Da ich einen ähnlichen Umbau für meinen IC 7200 und ein TELEX airman 750 beabsichtige, würde ich mich freuen, wenn ich Ihnen einige entsprechenden Fragen stellen dürfte. Das Airman 750 besitzt bereits einen eingebauten SMD-Verstärker, dessen Schaltung mir vorliegt. Dennoch sind mir dort zwei Dinge nicht ganz klar.

    • Hallo,
      da bin ich wahrscheinlich auch überfragt. Meine Vermutung wäre allerdings, dass die Schaltung mit anderen Headsets ähnlich funktionieren müsste. Schließlich lassen sich die Headsets alle in Luftfahrzeugen der General Aviation problemlos betreiben.
      vy 72 de Jens, DJ2UM

  6. Hello,

    Do you know if there is any difference with the plug port for the Yaesu and a Kenwood TM-281a? The specific setup that I would like to use is the Kenwood and the ASA HS-1A headset. Your assistance would be much appreciated.

    • Hi Josh,
      Sorry, unfortunately I have absolutely no information on the Kenwood product line.
      If you find something, feel free to post your insights here for the benefit of the community.
      vy 73 de Jens, DJ2UM

  7. Hi, Jens,
    Thanks for posting this circuit. I do have one question. Not sure what a 6k8 resistor is. Is that a 6.8 k ohm?
    Thanks, es 73, Gary KW4MG
    PS. Just had my H10-40 rebuilt at David Clark and they did an incredible job. It’s at least 30 years old, and it now looks and works brand new!

    • Hi Gary,
      Yes, you are correct. 6k8 means 6.8 kiloOhms.
      Great news on your refurbished DC headset, I didn’t know they offer this service.
      I upgraded to a Bose A20 last December. I thought it might make sense to protect my hearing a little bit better since I got my flight instructor rating last year and started to log about 100h+ annually. I have to say, the difference is remarkable.
      Best regards, vy 73 de Jens, DJ2UM

  8. Good afternoon from the USA,

    Thanks for this great information. Quick question. If I have a radio that provides a bias voltage of 8 volts rather than the 5 volts from the FT-897, how would you modify the circuit? Would you just change R1 from a 470 ohm resistor up and change C1 and C3 as well or would you merely change R1 to reduce further?

    Thanks!

    • Peter:

      It should actually work just fine. Here is a snippet I found on Wikipedia regarding the phantom power for aviation microphones: “[…]Phantom power is sometimes used by workers in avionics to describe the DC bias voltage used to power aviation microphones, which use a lower voltage than professional audio microphones. Phantom power used in this context is 8 to 16 volts DC in series with a 470 ohm (nominal) resistor as specified in RTCA Inc. standard DO-214.[18] These microphones evolved from the carbon microphones used in the early days of aviation and the telephone which relied on a DC bias voltage across the carbon microphone element. […]”

      So, according to this you should be just fine with leaving the resistor as is. Makes me wonder why it works with the 5V on my Yaesu rig, though …

      Best regards from Germany
      Jens

  9. Would you be interested in building me one. For
    A price? I have model number H10-37 Headset and a yaesu ft897d. Or draw plans so I may have one made. I think they would be a big seller on E-bay. Thanks for your time. Bill

  10. Jens,

    What would be required to power this with a 9 volt battery? While I have a Yaesu radio, I’d like to make this unit compatible with any radio (Kenwood radios do not provide a DC Bias voltage best of my knowledge) . Would the positive end of the battery go into the 470 Ohm resistor? Would about the negative end of the battery? Would this be connected to the ground of the radio? I plan to make different interface cables with ethernet on one end and the appropriate pin connector on the other.

    Thank you so much for you help.

  11. I use (the principle of) this circuit for the UFM A100T.
    This is the microphone extension for the Bose QC15, making it an ANR headset.

    Some changes :
    C’s changed to one 22uF capacitor.
    Output : only a fixed 1K resistor.
    In the UFM the output can be set (minimum is ok)
    All components fit inside a 8 pole microphone connector, which replaces the 5 mm jack plug.

    It works fine.

  12. Hi there Jens.
    This is exactly what I have been looking for. Thank you so much. I am looking forward to constructing this and seeing how it goes.

    • Don’t know and unfortunately I don’t have the means (access to radio) to test it … let me know if you find out more. But in general, you have to look for two things: (1) Does the radio provide the necessary phantom power for the mic (2) how is the PTT function controlled (the newer Yaesu radios ground the mic line through a 10k resistor). Other than that the circuit should be pretty robust.

  13. Hi jens
    i would like to know if my sennheiser headset hme-100 can connect with ft897 using your diagram.would appreciate if u can email me with detail diagram so i can build up my own.i cant find any 5.35mm in any elect store.
    thanks.

    9W2NDQ
    73

    • The HME-100 should work fine with the circuit. Finding the 5.35 mm socket can be a little bit of a hassle. You probably have to go to an aviation supply store. Try http://www.aircraftspruce.com for example. Another option would be to visit the next general aviation airport in your vicinity and locate the avionics maintenance shop. They will probably have some on stock.

      vy 73 de Jens, DJ2UM

  14. Pingback: Aircraft headset to ham radio adapter – Docs by Design

  15. We are starting a aviation unit here at our local sheriff’s office. We have installed a Motorolia PM400. My thought since we can not find a headset the will plug into the PM400 wanted to see if you would consider building a adapter box. My thoughts was to have someone add extra set plugs from headset with PTT switch on one ear cuffs to transmit the PM400. So in general they will be 2 sets aviation plugs in. One going to the aircraft’s intercom for aviation side, other set plugs going to the PM400 to transmit to other ground units.
    I have David and Clark Model H10-30
    Any advise would be appreciated.

    • Sorry for my late reply … I think when it comes to fixed istallations in aircraft you should probably contact your local avionics shop and ask them for advice. My preferred way would be to connect the radio to the audio panel and have it fully integrated in your avionics stack. If you have something like a Garmin GMA 340 installed you can connect up to transceivers. Let me know how you solve the problem.

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