Speech Compressor for FT-817, 818

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Speech Compressor - unleash your DX potential

***apparent improvement can be up to 6dB!***

Available ready-built or as as an easy-to build kit. Build time approx 40 minutes

817に効きます! その差は歴然。JH4DUQ - via Twitter

The FT-817 FT-818 is a great radio but the SSB speech power does lack "punch". This great little external AF dynamic compressor from Germany Box 73 will aid readability and maximise the performance of your radio (essential when using QRP). Speech Compressors work by raising the average level of your audio signal, giving greater "talk power".

Plug and Play! Connects between the radio and microphone (lead included). The compressor function can be switched in or out, the module draws its power directly from the transceiver (approx. 10mA). The compression level is adjustable. Modifications to the microphone or transceiver are not required.

Click here for instructions.

The compressor is also suitable for use with the FT-900, FT-857, FT-897 and FT-450 (all versions)


Speech compression is not recommended for use on FM

Occasionally people have problems plugging their microphone into the compressor. This is because the Yaesu microphones are fitted with an oversized rubber boot that shrouds the RJ45 connector. If the RJ45 connector does not click firmly into body of the speech compressor, gently retract the back rubber boot a few millimetres and the connector will engage properly (100% success rate!).


 Also available from our international agent(s):  



52 Reviews Hide Reviews Show Reviews

  • 5
    Speech Compressor 818

    Posted by Andy on 23rd Aug 2019

    I contest using the ft-818 on most bands vhf/uhf , since using this stations that normally have difficulty hearing me are bow hearing me, much improvement

  • 5
    Speech Compressor

    Posted by Egidijus on 3rd May 2019

    Ecxelent product ! Realy adds power level about +3dm, voice becomes clearly. Little bit tuning and to solder 3 parts.

  • 5

    Posted by Steve Richards on 8th Mar 2019

    I am using this with my FT857D. Worked straight out of the box. I'm getting reports of at least one S-point of improvement and punchier audio when switched in. I found it best to reduce the rig mic gain slightly. The device also seems to feature a noise gate which mutes the background noise when I am not speaking.
    A pleasing addition to my mobile/portable set-up.

  • 5
    Speech Compressor for FT-817-818

    Posted by Martyn Rickward on 23rd Dec 2018

    This is the latest version of the
    Speech Compressor which I purchased from SOTABEAMS a few weeks ago. The few stations that I have worked so far using the compressor and standard MH-31 microphone have said it has definitely improved the quality and level of audio from my old FT-817ND.

  • 5
    Speech Compressor for FT-817,818.

    Posted by Les Virgo on 3rd Dec 2018

    I recently purchased the Speech Compressor kit to use with my FT817nd. After a lack of spare time I assembled the kit & performed the suggested checks, all OK. I used the Compressor for the first time during the VKFF team championships & received very good reports. I have since used it during more activations both QRP & with my 45 watt linear amp. This is a keeper & I highly recommend it.

  • 5
    ssb on ft-817

    Posted by Aleksander Jensen on 29th Nov 2018

    The ssb mode is really kicking with this smal but effective compressor.

  • 5
    SB Speech compressor for Yaesu FT8*7

    Posted by William Sefton on 21st Nov 2018

    Makes one HUGE difference. Used mine in the CQWW SSB contest, and worked some nice DX (for a QRP SSB station) Well worth the money, and highly recommended. Also used a Sotabeam linked dipole......what a combo....

  • 4
    FT-817 Speech Compressor Kit

    Posted by Derek G1ZJQ/P on 11th Sep 2018

    Easy to assemble and worked fine without tweaking the pots from their 50% setting. Comments received on 2m SSB were that, while audio is sweeter without it, the difference in signal level is dramatic.

  • 5
    Gives your FT-81x the missing "punch" on SSB

    Posted by Mark Dammer on 27th Aug 2018

    Apart from a lot of advantages that made the FT-81x transceivers one of the classic QRP rigs, the lack of power on SSB is well known. This compressor makes SSB workable and gives the FT-81x the punch it needs.

  • 5
    Speech Compressor for FT-817ND/FT-818ND

    Posted by Gust ON6KE on 17th Aug 2018

    I had a 590 set-up with just a patch lead connected to it. A simple test but boy does it MAKE a difference transmitting on the 818ND with the processor on and off, a great deal of difference! It also feels as if the TX bandwidth is narrower with the processor in switched on.