Hello DK7FC Stefan,
I am seeing better SNR and more WSPR receptions in general with the
BPF in place, especially at night when the huge BBC broadcast signal
on 198kHz that's not THAT far from me becomes intrusive. During the
day there's not a lot of noticeable difference with and without the
BPF but at night I would need a lot of attenuation to stop 198kHz
swamping the receiver.
Thursday, August 23, 2018, 1:55:59 PM, you wrote:
> Hi Chris,
> Am 23.08.2018 14:38, schrieb Chris Wilson:
>> My method of testing
>> is a wide band commercial noise source and two series wide band amps
>> to up the level to something useable by my SDR, then look at the BPF
>> filter action on the display in HDSDR. I have a spectrum analyser but
>> am not very good with it, given the comfort I have using HDSDR I am
>> probably better keeping it simple! Sound OK?
> Yes, sure. You see what you need to see. The perfect tool. I also use
> SpecLab to check filter curves...
> For what do you need the BPF? Just for fun or do you have serious
> problems with DCF39 and HGA22? In the last case you may need to put some
> effort in the Q of the coils to get a sharper slope. Hand wound coils on
> pot cores, using RF litz wire seems to be best. I reached a Q of > 500
> if i remember correctly.
> But somehow my results have never been really satisfying...
> 73, Stefan
--
Best regards,
Chris mailto:[email protected]
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