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[Yaesu] Re: FT1kD (Low-level/Aux) AF OUT Interface

To: <yaesu@contesting.com>
Subject: [Yaesu] Re: FT1kD (Low-level/Aux) AF OUT Interface
From: wa.tworsx@verizon.net (Vince)
Date: Mon Jul 21 18:16:36 2003
Hello Rob (and Joe, W4JSI):

Thanks for taking the time to reply to my posting.  

The interface that I use here is homemade and very simple, Rob. It
includes two audio transformers (Radio Shack), one inserted in the LINE
INput (for receive audio) and the other inserted in the LINE OUTput (for
transmit audio).  I use two fixed value resistors (100k and 1k) that are
connected across the secondary winding to reduce the modulation audio
for the FT1kD. 

When I cabled from the AF OUT jack to the MICrophone input at the sound
card and ran MMTTY, I was able to see small peaks at the RTTY Mark and
Space frequencies, but printed text was very poor. That was a direct
cable connection between AF OUT (radio) and MICrophone input (sound
card).  While the sound card microphone Boost was enabled, I saw what I
think was 60 Hertz spikes; so, I will need to isolate that connection
channel with a (step up) transformer if I ever decide to use it again.
It was at this point that I observed that the front panel controls (AF
and RX MIX) appeared to affect the amplitude of the AF OUT signal (as
indicated by the MMTTY displays).  I will attempt to repeat that here,
because others have reported that their front panel controls do not
affect the AF OUT level, which is in agreement with the description
given within the Operating Manual.

At present, I do use the AF OUT signal to drive an external stereo audio
amplifier that drives the speakers used with my PC. Because
howling/distortion is present during transmissions on certain HF HAM
bands, my plan is to add a (step up) isolation transformer for that

Rob. there is no PATCH Audio out on my FT1kD. In my configuration, the
PATCH INput jack is used to receive the attenuated AFSK signal that is
derived from the sound card LINE OUTput signal. 

Joe, I am using VOX control, but will perhaps wire up a COM port for PTT
and a couple of relays, because I would like to have better operational
control while using SSB voice/SSTV. 

Can anyone here suggest a source for a step-up transformer?  The AF OUT
is spec as 200 millivolts, 600 ohms Z.    
73 and thanks again,
de ~ Vince ~

Robert Kennedy wrote:
> Hi Vince,
> What type of interface are you using?  Many interfaces introduce
> attenuation
> (using a resisitor or POT) on the line between the audio out of the
> rig and
> the line input of the sound card.
> Also check your sound card mic and line input settings of the sound
> card
> (via START -- SETTINGS -- CONTROL PANEL).  Many sound cards have the
> 20 db
> attenuation setting ON by default for the sound card mic connector and
> some
> do the same fo rthe line input as well.
> On the FT-1000D you should use the PATCH Audio out RCA jack instead of
> the
> STEREO mini audio out jack.  If you are using the later, the audio and
> mix
> controls will affect the signal going to the mic input of the sound
> card.
> (Also make sure you are using the right channel -- left or right).
> If all else fails, connect a small audio filter with a built in audio
> amp
> between the audio output source of your choice and the sound card line
> input
> jack to give you the control you want.
> 73
> Rob
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