[Elecraft] [K3] Sub RX and E-MU 0204

[Edward R Cole]

Joel,

Having a emu 0202, I wondered what the 0204 differences would 
be.  Looks to be an upgrade for win7.

You can take the emu stereo output as IQ input to SDR sw.  I do that 
for JT65B on 2m-eme.  I cheat a little by connecting the K3 line-in 
to the emu Headphone jack which has a manual level control (so I do 
not have to mess with sw level bar adjustments in the 
computer),  Receive audio levels are set with the L and R Mic 
control.  I usually do not change the K3 Line-in level from "10".

I think there is a place where you can disable soundcard tones in 
your computer OS, so those beeps and boops will not be 
transmitted.  My computer's original internal soundcard quit some 
years ago so using the emu is actually more convenient with the 
manual gain controls.

I also note that audio levels will change with programs.

I have diversity receive but export both main and sub receiver IF to 
two LP-Pan and on to a four-port soundcard (mAudio Delta44).  This 
gives me two IQ channels for special SDR sw that I run on eme.  I 
ensure the signals are in phase by running both LP-Pan from one LO 
(see mods under "Linrad" in the contents of "Tech Topics" on my website).

73, Ed - KL7UW

From: Joel Black <w4jbb at charter.net>
To: elecraft <elecraft at mailman.qth.net>
Subject: [Elecraft] [K3] Sub RX and E-MU 0204
Message-ID: <52D2BFA8.40800 at charter.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

A few years back, I bought a CreativeLabs E-MU 0204 for SDR applications
(i.e. SoftRock and Genesis G59). After buying a K3 and later a KX3, I no
longer needed the soundcard for SDR so it sat in a file cabinet on and
off for a couple of years.

I have tried on and off to make the 0204 work well with different
applications. I run Mac OS X 10.9.1 now so I am not as familiar (but I'm
learning) with different applications as I once was with Windows. For a
long time, I just ran with my old standby - a SignaLink USB.

Now, I know what a lot of you will say - the K3 will accept a soundcard
input directly from your computer and you are correct. The problem is
that I hear way too many Windows sounds over the air. It is my firm
opinion that a discrete soundcard for digital only operations is needed
in the amateur's shack.

Anyway, I ran with the SignaLink for years. It is very convenient in its
operation with the ability to accept a multitude of transceivers for
keying and input and output for sound. All of the controls are on the
front of the SignaLink with the ability to adjust both TX and RX levels
(and Delay although I've never found a use for that with my casual
operations). The one major drawback (in my opinion) was the mono-only
receive capability.

Yesterday, I finally figured out how to make the E-MU 0204 work with my
K3 and the ALC levels. In DATA A mode, the line input adjustment was not
quite fine enough. Testing with RTTY, at about a line input level of 4,
the ALC was three bars. At a line input level of 5, ALC was a solid five
bars with *no* flickering of the fifth bar. Yes, you could say I'm anal
about my TX drive, but as with Windows sounds being transmitted, there
are way too many amateurs who overdrive their transmit audio. I wanted
it to be correct and I finally figured out how to do it - the Audio Midi
Setup. After playing around with different sound settings on the Mac and
not being able to achieve what I wanted, I broke down and read the 0204
manual (imagine that!). The manual discusses using the Audio Midi Setup
on the Mac OS. After fiddling with those settings for a bit, I finally
got the K3 to transmit at four bars ALC with the fifth flickering.

Now, I am a bit befuddled as to why PSK31 seems to transmit at a lower
audio level. For PSK31, I have to fiddle a bit with the line input on
the K3 and it's usually just a single digit of fiddling, so it's not a
big deal. My only guess is that PSK31 has a lower audio transmit level
than RTTY.

The beauty of using the E-MU 0204 is with diversity receive, you can
hear both receivers with the soundcard - the left channel is one
receiver, the right channel is the other. You can do the same thing when
a DX station is working split. As far as I know, that is *not* a
capability which the SignaLink USB has.

My digital software of choice is Fldigi; however, I do not believe it
has a dual RX capability. There are other applications that do. For the
Mac, there is cocoaModem. It does not have the number of modes available
to it that Fldigi has, but it will allow you to operate the modes for
which I see most contests / operating events.

I have not yet tried the E-MU 0204 with my KX3 yet, but I am going to. I
am hoping that the headphone output on the 0204 will allow me to monitor
both transmit and receive audio. I miss that when using the KX3 on
digital modes although I know there are ways to get it.

I hope this is not too far off topic, but I thought I'd share what I
found using the E-MU 0204 and the K3.

73,
Joel - W4JBB




73, Ed - KL7UW
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