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Re: subaudible tones on FT-847 in satellite mode



on 1/3/03 9:04 PM, Wayne Estes W9AE at w9ae@earthlink.net wrote:

> FT-847 subaudible tone encoding is probably accomplished using the audio
> DSP.  Unfortunately, the FT-847 software defaults the audio DSP to the RX
> path when the radio is in full-duplex mode.  That's why the Speech Processor
> doesn't work in satellite mode (the speech processor function is also done
> by the DSP).  It's a shame that there is no menu to allow the user to
> specify the DSP path (TX or RX) when the radio is in full-duplex mode.

I think the speech processor is disabled because it raises the duty cycle
and hence the average power of the transmitted signal.  This could cause
more problems on the satellite and you want to use a little power as
possible.  I think that's why Yaesu did it that way.
> 
> Inflexible DSP path in full-duplex mode is one of several annoying software
> "features" of the FT-847.  Others include the excruciatingly slow Sub Tune
> speed and the screwed up band switch when FAST tuning mode is selected.
> There's also some flaky hardware design such as the AF gain and Mic gain
> controls which go from "nothing" to "too high" with a slight movement of the
> knob.

The volume control pot is easily fixed.  There's a couple resistors internal
that you can remove.  Then it's not so bad.  It's a very well known mod.

73,

Jon
NA9D

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