Message-ID: <4CCCA351.1070508@iup.uni-heidelberg.de>
Date: Sun, 31 Oct 2010 00:59:29 +0200
From: =?ISO-8859-15?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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References: <4CCC8022.90003@iup.uni-heidelberg.de> <004e01cb7883$96949580$4001a8c0@lark>
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Subject: Re: LF: Re: SBL-3+
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Hi Alan,

I want to try an alternative to the BF981 which runs in my current LF=20
grabber RX. It downconverts 137 kHz to 12 kHz and feeds the soundcard=20
with this 12 kHz signal. It is running not too bad but i have some=20
problems with temperature drifting bandpass filters (since weeks) and=20
have thrown them out of the Drain-to-Plus path. So, now the setup is=20
running with a 2 stage RC LPF. I have had some problems with a to high=20
125 kHz level on the soundcard input and have applied a series LC=20
circuit for 125 kHz now which reasonably solved the problem. But the LF=20
noise is now just about 10 dB above the soundcard noise, in the=20
afternoon. There is still a lack of sensitivity. This RX QTH should be=20
very well for a grabber antenna but currently the setup is the problem.
So i want to try something different, like a DBM. I am not an expert=20
here and can/have to learn a lot, it seems ;-)

73, Stefan

Am 31.10.2010 00:41, schrieb Alan Melia:
> Hi Stefan why a difficult to get mixer?? the IF port on most DBMs is DC
> coupled so feed the siganl in there and (i presume) mix up ?? Or is the
> RF/LO response still too high on the easily available ones?
>
> Alan G3NYK
> ----- Original Message -----
> From: "Stefan Sch=E4fer"<schaefer@iup.uni-heidelberg.de>
> To:<rsgb_lf_group@blacksheep.org>
> Sent: Saturday, October 30, 2010 9:29 PM
> Subject: LF: SBL-3+
>
>
>   =20
>> Dear LF,
>>
>> I want to try a LF converter using this mixer. Does anybody know a
>> (cheep!) distributor in Germany or EU for 1...3 pieces of it? I've just
>> found one where it costs about 40 Euro and this is to much!!
>>
>> 73, Stefan/DK7FC
>>
>>     =20
>   =20