Topic: RASPY Transmit Audio from Dahdidah using Netbook (2 replies)
#1     Tue Aug 04, 2009 1:41 am
Holly Hill, FL
Join Date: Aug 2007
Posts: 23
Subject: RASPY Transmit Audio from Dahdidah using Netbook

Hello Gang! It's been a very long time since I last posted here. That's cuz everything has been working so well. But now a new challenge!!! :roll:

My 6 year old Toshiba Satellite Notebook is now collecting Social Security :lol: having been relegated to the 4th string spares shelf. It has been replaced with an ASUS eeePC Model 1000 netbook which uses RealTek HD Audio electronics.

I installed Dahdidah and setup a serial to USB converter with my old reliable hookup cable with 3 gator clips and the 9 pin D-sub connector. I chose the KS driver, the proper COM port and started keying. Instead of the usual pure clean tone I heard this awful raspy buzz. :oops: Hmmm....not good. :evil:

Changed to the DirectSound driver and the tone was pure but the bloody lag was still there. Can't send code with that delay. MME causes Dahdidah to produce a continuous tone and nothing else. Yikes!!!! :shock:

Tried another USB to Serial adapter and its drivers and the results are the same.

Since this Netbook does NOT have a CD ROM drive my last option, installing the Voyetra Turtle Beach Amigo External USB Sound Card Accessory could not be done in this session. (That will happen tomorrow!) I'm hoping that the completely different audio electronics of the Turtle Beach device will work more better.

But I wonder..... Has anyone else resolved a similar RASPY tone problem on their notebook/netbook???? If so, how did you do it?? Don't see any notes in this thread on this detail so I'm guessing I'm the first to post about it.

I'll report on the results of the Turtle Beach setup shortly.

With all fingers and toes crossed, I bid you 73, :D

Frank KB4T
#2     Wed Aug 05, 2009 4:16 pm
Join Date: Aug 2006
Posts: 724

Hi Frank. You could try working the Dahdidah Amplitude slider against your Windows Wav slider to see if something is getting over-driven.

You could try upgrading to the latest RealTek driver for this computer.

Is it possible you are hearing a speaker rattle and your sine waves are pure?
Try hooking up headset or external speakers.

I bet the turtle beach will work. Let us know.

73, Doug
#3     Sun Aug 23, 2009 12:59 pm
Holly Hill, FL
Join Date: Aug 2007
Posts: 23
Subject: No Joy even with 2nd audio card

I regret to report that my experiments with a second audio card have not been successful. :cry:

The raspy quality is NOT affected by any level settings and is definitely not a physical manifestation. The audio distortion is produced within the netbook PC unquestionably no matter how levels are set or inputs chosen. Different RealTek drivers have no effect.

I had no trouble getting the Voyetra Turtle Beach USB external audio "card" to work with my Asus eeePC netbook. It functions perfectly in every way and is even better than the built in audio electronics. But even with the external audio "card." DahDiDah continues to turn raspy within a few dits or dahs consistently when using the Windows WDM-KS driver.

WDM-KS is the only driver within DahDiDah that produces clean CW tone without any delay between the time the key is closed and tone is produced. MME and Windows DirectSound drivers both produce clean audio with no raspy artifacts EVER but they both also produce unnerving and confusing delays between the time the key is closed and the tone is produced. I simply can't send properly at QSO speed with the delays.

I'm disappointed, of course, but not completely surprised. While I don't know the specifics, the eeePC handles audio differently compared to my desktops or other notebooks. Clearly, DahDiDah is doing something that the audio processing architecture of the netbook simply can't handle.

Even though I can't get DahDiDah to work on the eeePC netbook, I am NOT giving up CW operation on QSONet when I travel. Keeping in mind that CW on QSONET is nothing more than audio (just like our voices) all I need to do is produce sine wave audio tone at a level high enough to drive the mic input of the netbook and the CQ100 software.

DahDiDah is basically a very adjustable sine wave audio oscillator and keyer. Since I can't use DahDiDah to produce dits and dahs with sine wave audio output, I need to duplicate that capability "externally." To achieve that I use an MFJ 554 Classroom Sine Wave Output Code Practice Oscillator, a simple coupling cable and the keying devices of my choice.

In essence, I have to carry a few more items in my QSONET Travel Kit but it's worth the effort! I use a foam-filled Pelican case large enough to carry everything. In the kit are the following items:

MFJ 554 with wall wart
Coupling cable (554 to PC mic input - details below)
K1EL K40 Keyboard & Paddle controlled electronic keyer with wall wart
Vibroplex Straight Key
Vibroplex Bug
Vibroplex dual lever keyer paddle
Miscellaneous gator clip leads and 12V power leads for 554 & Keyer

The coupling cable is very simple. I use a simple shielded audio cable (single center conductor and shield) with a 1 MFD 50V garden variety capacitor wired in series with the center conductor. Connectors to match the external speaker output of the 554 and the mic input of the netbook are installed on the ends.

The 554 allows me to adjust the level driving the netbook as well as the pitch. Pure sine wave output is clean and pleasant to the ear.

Eventually my netbook will fail/get stolen/get dropped and will be replaced. Perhaps its successor will get along better with DahDiDah. Perhaps DahDiDah will evolve in a way that works better with smaller PCs. Until either day comes, I'm still good to go for QSONET CW. Where there's a will, there's a way.


Frank KB4T

Copyright ©2013 Cormac Technologies Inc.