[Trlog] DVK

Pete Smith n4zr at contesting.com
Tue May 8 09:07:51 EDT 2007

For recording, I suggest Audacity, a free application that is very good for 
trimming audio files to precise length.  It also has the capability of 
setting audio files to a consistent peak level, without clipping.  It makes 
it easy to get good-sounding, consistent messages.

Setting the level to your radio is a little trickier, because it depends on 
whether you must feed the sound card's audio to a microphone input or can 
put it into a line-level jack on the back panel.  For the former, you need 
a voltage divider; for either, you may need isolation transformers to help 
eliminate hum.  Either way, you need to set the playback level of your 
sound card so as to have it as close as possible to the level from your 
normal voice.  With my simple interface and a duplex capable sound card, I 
feed my microphone through the sound card.  That way I can set the sound 
card's microphone gain to match the recorded files, and then control both 
levels to the transceiver simultaneously with the line out level control.

Hum can be difficult, particularly with feeding audio to the microphone 
jack - I found that I needed both isolation transformers and VERY good 
connections between the computer and transceiver chassis.

73, Pete N4ZR

At 02:04 PM 5/7/2007, Fred Jensen wrote:
>Mirko S57AD wrote:
> > Actually, there are 4 ways:
> >
> > * Soundblaster card  & SBDVP TSR prog,
> > * DVP by K1EA
> > * W9XT card
> > * External DVK
> >
> > I tried first two successfully. but had some issues (by cockpit error)
> > with external DVK.
> >
>I tried the first also.  Getting SBDVP to run right was frustrating, but
>I finally managed.  My logging confuser is the very old 486-33 our
>youngest son used in college about a dozen years ago, and I had to set
>up a RAM disk for the .wav files to get it all to work.  Off the hard
>drive, the audio played erratically.
>The two major problems were:
>1.  Getting acceptable .wav files recorded.  Getting rid of background
>noise, getting enough bass into it, and keeping extraneous hum out.
>2.  Getting the audio into the radio without hum and at the proper level.
>I finally gave up, and since I generally operate only CW and some RTTY,
>it's OK.  Incidentally, an informal survey of DVK quality during last
>year's SSB Sweepstakes seems to have indicated that 9 out of 7 DVK's are
>essentially unintelligible :-)
>Fred K6DGW
>- Northern California Contest Club
>- CU in the 2007 CQP Oct 6-7
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