Message-ID: <5C293558.6010606@posteo.de>
Date: Sun, 30 Dec 2018 22:15:04 +0100
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <976652757.10789891.1546166793929.ref@mail.yahoo.com> <976652757.10789891.1546166793929@mail.yahoo.com> <5C28AE1C.1020707@posteo.de> <alpine.DEB.2.11.1812302117390.1809@mailn.lipkowski.org>
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Subject: Re: ULF: Carrier on 2970.01 Hz
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Hello Jacek,

Did you just look into a spectrogram or did you try to produce a 
spectrum peak from your data storage?
Do you use the -a th=x function in vtfilter.
I think i have the latest version of vlfrx-tools. It is worth to 
upgrade. Instead of the band pass filter i'm using a low pass and a high 
pass. After a lot of trials i tend to use this setting as a standard:
vtread -T2018-12-30,11:17,+2h /database | vtcat -p | vtfilter -a th=5 -h 
hp,f=1750,poles=8 -h lp,4250,poles=8 | vtblank -a25 -d0.0005 -t100 | 
vtmult -f2970.01 | vtresample -r240 | vtresample -r10 | vtraw -oa | 
ebnaut -dp8K19A -c4 -r10 -v -f15 -f16 -N5 -M'*****' -k27 -S12

The ebnaut message is just a dummy for a 2 hour long carrier 
transmission. The output of that command line will show the S/N of the 
spectrum peak in its bandwidth (1/duration).
The autonotch filter is important in that frequency range and can decide 
between failed and success!

I would be interested in the result on your side.

73, Stefan


Am 30.12.2018 21:45, schrieb Jacek Lipkowski:
> Ufortunately i didn't receive anything here. Not very exciting but i 
> believe that negative results should also be reported.
>
> The spectrograms:
>
> https://klubnl.pl/grabber/grabber_sq5bpf_2970.png
> https://klubnl.pl/grabber/grabber_sq5bpf_2970_avg.png
>
> Right now i use the same settings as on my 5170Hz grabber: a 3kHz wide 
> filter centered on 2970Hz, followed by vtblank  -a1.4 -d0 -t100 
> (vtblank from old vlfrx-tools). I would be grateful for any 
> suggestions how to improve this, maybe the filter is too wide (and 
> lets too many 50Hz harmonics through. which upset the blanker).
>
> The antenna isn't optimised for ULF.
>
> VY 73
>
> Jacek / SQ5BPF
>
> On Sun, 30 Dec 2018, DK7FC wrote:
>
>> Date: Sun, 30 Dec 2018 12:38:04 +0100
>> From: DK7FC <selberdenken@posteo.de>
>> Reply-To: rsgb_lf_group@blacksheep.org
>> To: rsgb_lf_group@blacksheep.org
>> Subject: ULF: Carrier on 2970.01 Hz
>>
>> Hi ULF,
>>
>> The accu is fully recharged and i am on the hill again, transmitting 
>> on the ground loop antenna. This time, the accu has even more power. 
>> The TX power is 520 W (!), the DC measurement tells i need just 64 V 
>> for 1 A, and now, at 2970.01 Hz i am getting a record antenna current 
>> of 2.75 A!!
>> The carrier ison the air since 11:17 UTC and i intend to run it for 2 
>> hours again, like yesterday.
>>
>> Reports are welcome :-)
>>
>> 73, Stefan
>>
>