[Elecraft] Planning the next filters

[Don Wilhelm]

There seems to be an ongoing concern about audio levels for digital 
modes.  This is not confined to the SignaLink, but applies to any and 
all soundcards used for digital modes.

There are at least two audio level controls - the Line In gain, and the 
soundcard output level (set in the computer for most soundcards, but 
with the front panel knob on the SignaLink).  There is also a 3rd 
control in the software application often marked "POWER".  Those should 
all initially be set midrange, and then changed a bit from there to 
produce 4 bars on the ALC meter with the 5th bar flashing.  That should 
keep you out of the clipping level.  If any controls are at a very high 
or low range, that is when you will run into clipping problems or 
insufficient audio drive.

For more detail and explanation of 'why', see the article on my website 
www.w3fpr.com.  Scroll down to the last article in the left column and 
click on the link.

Data mode operation does not require an exotic soundcard, most any will 
work.  The important parameter for soundcard data modes is the noise 
floor available for the soundcard.  Soundcards for Panadapter use need 
to have a sampling rate equal to (or exceeding) the bandwidth to be 
displayed, but that is not an important parameter for digital modes.  In 
other words, a 16 bit 32k (or greater) soundcard will work well for data 
modes.  The more expensive soundcards will likely have a lower noise 
level, but that is not guaranteed.

73,
Don W3FPR

On 3/9/2018 6:58 PM, Bill Frantz wrote:
> Since SignaLinks seem to be a continuing topic, one thing I noticed with 
> mine is that the manufacturer seems to have been upgrading the design. 
> When I first heard (probably from Jim) that there were problems with the 
> SignaLink, I found a web site with directions for fixing some of them. 
> So I warmed up my soldering iron and opened my SignaLink. When I looked 
> carefully, every single one of the issues on the web site had been 
> addressed in my unit.
> 
> I got a Tascam 24 bit device, which I used for several years, but it 
> wouldn't work on my Linux BeagleBone, because of the lack of drivers. It 
> worked well on my Mac. Now I'm using the KIO3B upgrade to my K3 and am 
> quite happy with it. The SignaLink has moved to my portable KX3 station, 
> where I'm looking for a smaller, lighter solution.
>