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DYC-817 speech processor for FT-847



A week or so ago I received a DYC-817 speech processor kit in the mail from
Funkamateur in Germany.  The color instruction sheet made it very easy to
assemble the kit.  This unit is intended to be used with a FT-817, so the
supplied connectors do not mate with the FT-847 microphone connector.  The
speech processor came with a pigtail of 8 conductor ribbon cable with a
RJ-45 connector.  I didn't use that, and instead supplied my own round 8
conductor cable and a round microphone connector that plugs into the FT-847.
I also modified the unit to be used with a Heil headset.  To do that, I
added a 3.5mm round microphone jack to the rear of the enclosure and a
momentary contact PTT switch to the top of the enclosure.

The speech processor didn't work when I first plugged it into my FT-847. The
problem was because the 5V pin on the microphone connector was loading down
to about 1V.  This indicated a defect in my FT-847, because the 10 mA load
of the speech processor should only load down the 5V pin to about 4.88V
(there is a 10 Ohm resistor in series for short circuit protection).  I
opened the radio and hacked in 5V to the microphone connector through a 12
Ohm resistor.  That fixed the problem with my radio.  I hope the situation
with my radio is due to a defect in my radio only.  I tested a K9PO's FT-847
and his powered the speech processor properly, as expected.

The speech processor has potentiometers inside to adjust the gain and the
compression.  K9PO and I tested the speech processor on AO40, and determined
that a "middle" compression setting gives the best intelligibility when the
signal is down in the noise.  We also experimented with the best setting of
the LSB carrier injection point (extended menu #97).  We found that a
setting of +6 reduced the bass of my voice significantly, without making me
sound too much like a quacking duck.

So if anybody would like to add a "satellite mode" speech processor to their
FT-847, the Funkamateur DYC-817 is entirely functional if you're willing to
modify it a bit to mate with the FT-847 microphone connector.  The price is
$22, plus $7 for airmail shipping from Berlin, Germany.
http://www.box73.com/cgi-bin/box73

This speech processor can be handy if you use a FT-847 and your uplink power
is marginal for AO40.  In my case, I plan to use it with my portable AO40
setup that has a small uplink antenna.

Wayne Estes W9AE
Mundelein, IL, USA


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