Re: VLF: First VLF detection DL > EA

[DK7FC <selberdenken@posteo.de>]

Hello Jacek, Paul, VLF,

Great results! And thanks for your greatly working grabber. I did never 
expect that the effect is so expressed. As Paul says, it may be worth to 
do a series of optimisations to find optimum filter responses for the 
special band with it strong 'neighbour' stations.
Would be interesting to see how strong JXN and HWU can become in VK7 for 
example!!! :-)
Regarding the notches inside the passband. How 'deep' is the notch in 
vlfrx-tools? I think there can be an improvement if the stop-band 
attenuation is only as high as necessary, say 20 dB for JXN, not as high 
as possible (> 100 dB).
73, Stefan


Am 07.12.2017 08:26, schrieb Jacek Lipkowski:
> On Wed, 6 Dec 2017, Paul Nicholson wrote:
>
> > vtfilter -e eqmap -h bp,f=17470,w=3000 -h bs,f=16400,w=600 
> > -hbs,f=18300,w=800
> with your filtering settings i immediately went from no signal to 
> great signal on my grabber:
> https://klubnl.pl/wpr/en/index.php/klubnl-pl-grabbers/tymczasowy-grabber-sq5bpf-do-testow-stefana-dk7fc-na-17-4701hz/ 
>
> i will reprocess the whole grabber window from 2 december, and after 
> that have the grabber updated live again.
> > Maybe that's the problem with this band then, just getting
> > the right filtering before the blanker.
> seems so.
>
> btw what is the reason to use a 3kHz filter before the noise blanker 
> and not a narrower one? i can understand the reason for not using 10Hz 
> bandwidth, but why not 1kHz?
> i was wondering how you got at the 3kHz figure?
>
> VY 73
>
> Jacek / SQ5BPF