From: "jannsen" <0482183881-0001@t-online.de>
To: rsgb_lf_group@blacksheep.org
References: <9881.200103201602@gemini>
Subject: Re: LF: Wolf Tests
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
Date: Wed, 21 Mar 2001 19:02:04 +0100
Message-ID: <14fmvs-1iUsMaC@fwd05.sul.t-online.com>
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Sender: <majordom@post.thorcom.com>

James Moritz schrieb:

>
> The obvious problem is how to determine the soundcard error, if 
> you don't have a accurate audio frequency source. I used the 
> reference output of my synthesiser divided doown to 1kHz (and 
> filtered; a fairly clean sine wave seemed to be neccessary to avoid 
> aliasing problems with the soundcard). You could use the RX audio 
> out, but only if you knew what the RX frequency error was to within 
> a small fraction of a Hz. 

> Cheers, Jim Moritz
> 73 de M0BMU

Hi Jim and all,
audio qrg source out of ur old PC does it too. take Rik`s QRS-progr, switch 
setup/sound/dfcw/enable/fill in the qrg u want in both dash- and dot-window the 
same qrg. 
hardware: take the speaker output (kill the speaker as Rik suggested), form the 
needle-waves into sinus-waves (I took out of my junk-box a pot-core 330mH, 
1,8mikroF and 100nF for c1 and c2 of a Pi-Filter for transforming 10ohm to abt 
6kohm)and measure the qrg. Taking 1000Hz  out of my junk-pc (486/66Mhz with the 
motherboard crystal tempcompensated)in the above described manner the counter 
shows 1000.0706Hz to 1000.1804Hz  constance over 4 hours.
regards
Uwe/dj8wx