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):  



41 Reviews Hide Reviews Show Reviews

  • 5
    It Does What They Says it Will Do

    Posted by VE5KC on 5th Mar 2018

    I looked at several options for improving my signal on SSB. It seemed that some kind of speech processor add on was needed for my FT-817..

    There are several options available from modifying your microphone or adding a circuit in the rig. I didn't feel comfortable with modifying my radio. The Sotabeams (inline) speech compressor looked to be the answer.

    I ordered the Sotabeams speech compressor ,from England and it arrived at my QTH two weeks latter. It was easy to install, only requires plugging it in between the radio and microphone.

    The first thing that was obvious, according to the power output meter on the 817, I was putting out more power. On air tests confirmed that I could be heard much better ,with the Speech Compressor making a big difference. It easily gave me the one S unit or better of improved signal as claimed.

    My first few contacts gave me reports of some audio distortion and comments that I was driving the mic too hard. You need to remember (I forgot this in my hurry to test it out) to adjust the microphone audio level for use with the compressor! ) My normal mic setting without the compressor was 50. With the compressor inline, it works best set to 30.

    I am happy with the Sotabeams compressor, it does what it says it will do and gives a better signal.

  • 5
    It Makes such a difference!

    Posted by Dave Lucas G8XDD on 24th Feb 2018

    The Sotabeams speech compressor does make a great difference when running QRP. I had 3 qso's this afternoon with my FT817 on 80metres, 2 of which recorded me and played it back. It makes 2 clear S points difference said one of them. Can't wait to take it out portable on some SOTA summits.

  • 4
    lack of instructions.

    Posted by Doug on 23rd Feb 2018

    forgot to mention -complete lack of instrucions and no indication of where to find them.can you alter the compression and how do you do it?why don't you put a pdf on the blurb-do it properly sotabeams! g4moi

    [Admin - thanks for your feedback. The package had a label on which clearly indicated where the instructions are, www.sotabeams.co.uk/downloads In your excitement to use the product you must have missed reading this information? I have today added a link from the product page for people who don't read the label.]

  • 4
    ft817 improved

    Posted by Unknown on 22nd Feb 2018

    shoddy case -could come apart.no visible sign of fixing the two halves, so looks as if might part sometime.otherwise definitely great reports for my ft817 audio.also have to peel the boot back on the connecting lead to insert it into one end-irritating.could be improved,but good buy g4moi

  • 4
    Excellent add-on for the '817

    Posted by Steve Ellis on 18th Feb 2018

    I bought the kit, which arrived well-packed, but without assembly instructions - you have to go to SotaBeams' download page for that. The instructions are in English and German, but perfectly adequate for the kit assembly. There isn't much soldering to do as most of the (surface mount) components are pre-assembled on the board. There's just a single surface mount capacitor to solder in, plus the sockets at each end of the board, and a couple of pots. Testing instructions are provided are easy to follow and well-worth doing, especially as the unit draws current from the transceiver itself, and excessive draw here could damage the (in my case) FT 817. As recommended I left the pots in the settings at which they were supplied and have seen no need to make further adjustments: the performance is very good. In my case the device turned an uncopiable signal on Top Band into a perfectly readable one. The only minor gripe concerns the supplied case, which although it fits OK is a bit flimsy and has no provision for ensuring that it doesn't fall open in use, plus there are no cut-outs to access the pots should you wish to adjust the unit later on (but there is a correctly positioned cut-out for the on-off switch). I held my case together with a couple of pieces of insulating tape, but would have preferred to use screws - no provision is made to screw the case together. Could be glued I suppose, but that's a bit permanent! But for the case issue I'd have given it 5 stars, because it clearly "does what it says on the tin" and I've had excellent reports on-air.

  • 5

    Posted by ok1zhv@email.cz on 17th Feb 2018

    no problem with compressor

  • 5
    Works perfectly

    Posted by Paul on 14th Feb 2018

    My ready built unit didn't work originally. After a bit of head scratching, I realised the stickers were located at the wrong end of the processor! Once swapped over, all worked properly. A quality control issue which Richard acknoledged but not the end of the world!

    The unit works really well (correctly oriented), highly recommended.

  • 5
    Gives the extra 6 dB you need.

    Posted by Rob W4ZNG on 11th Feb 2018

    Five watts is just at the threshold of "enough" and this little jewel will lift you over that threshold and into the Realm of Being Heard. I've made more SSB contacts on my 817 in the last two weeks than I'd made in the previous six months. Everybody's got their own ideas to customize these radios, but this is the one upgrade I'd recommend for every 817 out there.

  • 5
    FT817 Speech Compressor

    Posted by Alec Adams on 4th Feb 2018

    Works well and easy to build and install