Tnx Stefan for info. I do have a dsp/ variable bandpass filter arrangement
already, that helps coniderably.
de mal/g3kev
----- Original Message -----
From: "Stefan Schäfer" <[email protected]>
To: <[email protected]>
Sent: Thursday, August 25, 2011 1:49 PM
Subject: Re: LF: Re: KEV...
Mal,
You cannot eliminate it but reduce it significantly. And the blanker
helps a LOT rejecting the sferics! This is a big improvement during CW
reception. The loud cracks are much weaker!
First i would suggest to add a about 2 kHz wide band pass filter that
cuts the strong peaks of DCF and HGA. The sidebands during a telegram
will then be in the passband but the carrier is outside. In the SL
Filter box i choose a center frequency of 137.3 kHz, bandwidth=1.5 kHz,
slope=0.75 kHz.
The noiseblanker settings are: ramp time= 2 ms, trigger peak/avrg= 9 dB,
pre- and post-trigger = 0.5 ms, time constant = 1 s.
Ensure to have installed V2.76b18 or later. There have been changes on
the noiseblanker functions in these new versions.
The filter is applied in the filter box, between L3 and L4, the
noiseblanker is applied in "left blackbox 2" (between L4 and L5).
73, Stefan/DK7FC
Am 25.08.2011 10:41, schrieb mal hamilton:
> Stefan
> What is the optimum setting for the Notch filter in Speclab to eliminate
the
> qrm on 138.5 Khz
> mal/g3kev
>
> ----- Original Message -----
> From: "Stefan Schäfer"<[email protected]>
> To:<[email protected]>
> Sent: Wednesday, August 24, 2011 11:32 PM
> Subject: LF: KEV...
>
>
>
>> Mal, you are visible even in that heavy QRN! Haven't thought this is
>> possible.
>>
>> 73, Stefan
>>
>>
>
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