> Date: Sun, 30 Dec 2018 22:15:04 +0100
> From: DK7FC <[email protected]>
> Reply-To: [email protected]
> To: [email protected]
> Subject: Re: ULF: Carrier on 2970.01 Hz
>
> 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 <[email protected]>
>>> Reply-To: [email protected]
>>> To: [email protected]
>>> 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
>>>
>>
>