Date: Fri, 4 Jan 2019 22:59:20 +0100 (CET)
From: Jacek Lipkowski <sq5bpf@lipkowski.org>
To: rsgb_lf_group@blacksheep.org
Subject: Re: ULF: Carrier on 2970.01 Hz
In-Reply-To: <5C2C9BF1.2090609@posteo.de>
Message-ID: <alpine.DEB.2.11.1901042256050.1809@mailn.lipkowski.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> <5C293558.6010606@posteo.de>
 <alpine.DEB.2.11.1901021028190.1809@mailn.lipkowski.org> <5C2C9BF1.2090609@posteo.de>
User-Agent: Alpine 2.11 (DEB 23 2013-08-11)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org

Hi Stefan

Unfortunately no detection on 2470 and 2970 (especially after Markus 
noticed that i'm trying to receive the wrong frequency :). Could you try 
5170 and 6470Hz?

VY 73 ES HNY 2019

Jacek / SQ5BPF


On Wed, 2 Jan 2019, DK7FC wrote:

> Date: Wed, 02 Jan 2019 12:09:37 +0100
> From: DK7FC <selberdenken@posteo.de>
> Reply-To: rsgb_lf_group@blacksheep.org
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: ULF: Carrier on 2970.01 Hz
> 
> Hi Jacek,
>
> Are you sure the x-axis label is correct?
> In vtblank, you use -t1000, not -t100 ?
> You need to determine the carrier S/N. I usually take an EbNaut message 
> having the same length, containing stars (*****), which is equivalent to a 
> carrier. Then the decoder tells me the carrier S/N.
> So, try:
>
> Am 02.01.2019 10:33, schrieb Jacek Lipkowski:
>> vtfilter -a th=5 -h hp,f=1750,poles=8 -h lp,f=4250,poles=8 | vtblank -a25 
>> -d0.005 -t1000
> and then | vtmult -f2970.01 | vtresample -r240 | vtresample -r10 | vtraw -oa 
> | ebnaut -dp8K19A -r10 -c4 -S12 -N5 -k27 -v -f15 -f16 -M'*****'
> There you need at least 14 dB S/N for a valid detection.
>
> 73, Stefan
>
>
>
>> 
>> Does that count as a reception?
>> 
>> VY 73 es HNY
>> 
>> Jacek / SQ5BPF
>> 
>> 
>> On Sun, 30 Dec 2018, DK7FC wrote:
>> 
>>> Date: Sun, 30 Dec 2018 22:15:04 +0100
>>> From: DK7FC <selberdenken@posteo.de>
>>> Reply-To: rsgb_lf_group@blacksheep.org
>>> To: rsgb_lf_group@blacksheep.org
>>> 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 <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
>>>>> 
>>>> 
>>> 
>