Demons DX´ers

ESSB en Yaesu FT-857 y FT-897

This modification is for the Yaesu FT-857D / FT-897D models

I did some research regarding the possibility to install a wider filter for SSB in my FT-857D.

It turned out that Collins (Rockwell Collins) do produce a 3.8 kHz wide filter that fits directly into the small print on the Yaesu XF-115C 455kHz CW filter (500Hz bandwidth).

This means that you have to sacrifice the 500 Hz Yaesu filter.

I did purchase the 3.8 kHz filter (526-8710-010) from Collins, but the price is rather high ($210 plus tax and shipping).

The -6dB bandwidth of this filter is 3.8 kHz , -60dB bandwidth is 10 kHz. Insertion loss is 5dB.

Simply un-solder the 500 Hz Yaesu filter and install the Collins filter. Please use a vacuum un-solder tool for removing the solder on the 500 Hz filter. This is fast and easy. Solder in the Collins filter. The radio will automatically detect the filter, of course it will show 500 Hz in the display.

For selecting the 3.8 kHz filter in RX, quickly touch the FUNC button and turn the SELECT knob to MENU MFn where you can select CFIL (2.3kHz ceramic filter) or the 500 (now 3.8 kHz Collins filter). This gives you a very open and rich sound in SSB.

Please note that the internal speaker in the FT-857D / FT-897D has a VERY limited audio range and will not be suitable to give you any wideband ESSB RX audio. You MUST use an external speaker, I use the small bookshelf speaker PROSON SAT 51RR mkII with great results. You should connect a similar bookshelf speaker to hear for yourself. Please try different speakers until you find the one that sounds good.

Go to MENU 086 and select TX IF FILTER 500 Hz for TX bandwidth 3.8 kHz.
I do use the Yaesu MD-100 desktop microphone with great results, no external equalizer. You might want to adjust MENU 016 (CAR LSB T) to - 100Hz for added treble in LSB TX mode, and MENU 018 (CAR USB T) + 200Hz for added treble in USB TX mode.

Please note that the original hand microphone has a very limited audio range and will not be able to give you any wideband ESSB audio. It will probably work OK, but do not expect too much regarding the audio.

The MD-100 is a lot better, essentially flat from 100Hz to 1000 Hz and a really nice peak at +10dB from 2000 Hz to 3500 Hz. A very good microphone. Please note that speech distance should be around 12 to 15 cm., mic gain at around 30 - 50 %. No COMP, or at least keep COMP GAIN at 35 % or lower because it will easily be distorted.

Good luck.

LA4AMA
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