How to make the FT-817 Contest Friendly with a BX-8×7

If you are working CW the narrow filter is a must and the SSB filter can help with helping he front end deal with the kilowatters but how does one get heard?

The BX-8×7 : Dynamic Compressor kit V2.0 for FT-8×7  is an Easy to build external Dynamic Compressor designed by a german ham and  is ideal for QRP operators

It is especially for the Yaesu FT-817, but can also be used for other transceivers with the same microphone interface such as the FT-857, FT-897 or FT-900.

BX-8x7IMG_3229
When transmitting SSB, dynamic compressor increases average transmitted power, and thus the audibility of a weak signal at the distant receiver, by at least one S-unit. This accessory is of special interest to amateur radio operators who work with lower transmitting power or wish to be better heard in a pile-up.

Check the link out for an audio sample from a real QSO

MP3 file with two CQ calls during a summer thunderstorm situation. First call made without compressor, the second with the compressor turned on.

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Based on SSM2165 (Analog Devices)
PCB with all SMD parts preassembled.
Powered over RJ45 cable (10 mA), no power supply or battery required.

The build time is less than 2  hours and makes an excellent addition to your 817 kit. I have taken a scope to the radio and can confirm it does add about an S unit to your talk power by use of the compressor

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2 comments

  1. Andrew VK1AD · March 17

    I purchased the kit in 2016. Brilliant, works exactly as described and no RF feedback in to the microphone line. 🙂

    73, Andrew VK1AD

    Liked by 1 person

  2. ve3ips · March 17

    I can assure you Andrew that the Australians are ahead of the adoption curve over the canadians

    Like

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