Re: LF: Korea 24.1 kHz and 25.0 kHz

[Markus Vester <markusvester@aol.com>]

Thank you for this interesting information.

I guess the TDOA technique may be hampered by the narrow bandwidth and periodic structure of the signal waveform (c / 100 Hz ~ 3000 km). Nagoya is "only" about 950 km east of Mokpo so the result might still be ambiguous.

From here, I can only tell the coarse direction "northeast" which would fit to both sites.

Best 73,
Markus (DF6NM)

 

-----Ursprüngliche Mitteilung-----
Von: Roman <rw3adb@YANDEX.ru>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mo, 3. Sept 2018 20:10
Betreff: Re: LF: Korea 24.1 kHz and 25.0 kHz

Hello Markus!

TNX for long SWLing for us!
Look, Vadim aka KARAPUZ - UA6SWL(this is nick name at pskreporter, not real call, he is unlis and SWL) make a some direction-finding laboratory work by KIWI-SDR reseivers. He use 5 receivers and find QTH around Nagoya, Japan.

Russian forum from here:

http://www.radioscanner.ru/forum/topic24687-14.html#msg1389739

Vadim's answer to us:

http://www.radioscanner.ru/forum/topic24687-14.html#msg1390104

Coordinates 34.00N 137.00E - ~100 km's far from Nagoya.

73!
Roman

> I looked through some stored colour-DF grabber captures. It seems that the South Korean transmittter has been alternating between 24.1 and 25.0 kHz on a monthly basis. As far as I can see, the scheme was
>
> Month in: ------2017------ | -------2018-------
> 25.0 kHz:   7 8 9             | 1 2 3       7  9
> 24.1 kHz: 6       10 11 12|        4 5 6  8
>
> Best 73,
> Markus (DF6NM)
>
> -----Ursprüngliche Mitteilung-----
> Von: P. W. Schnoor <pws@df3lp.de>
> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> Verschickt: Mi, 8. Aug 2018 22:50
> Betreff: Re: LF: 24.0 kHz sig - NAA?
>
> O.K.
>
> Go to:
> https://groups.yahoo.com/neo/groups/VLF_Group/conversations/messages/25189
>
> Read those ITU infos.
>
> Push: "Show message history"
>
> Read what Markus wrote there.
>
> May be he describes exactly what R6LDD's image shows.
>
> Peter, df3lp
>
> On 08.08.2018 19:01, hvanesce@comcast.net wrote:
>> In the mid 60's I wished that my receiver (BC-453/4/5) would reach 24 kHz.
>>
>> Still works and still wish; that much stayed the same :-)
>>
>> Jim AA5BW
>>
>>
>>
>> -----Original Message-----
>> From: owner-rsgb_lf_group@blacksheep.org
>> [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of John Rabson
>> Sent: Wednesday, August 8, 2018 12:32 PM
>> To: rsgb_lf_group@blacksheep.org
>> Subject: Re: LF: 24.0 kHz sig - NAA?
>>
>> How times change. In the late 1960s I received NAA on a hot summer afternoon
>> in the town of Harlow, about 30 km north-east of London. The antenna was an
>> L about 80 m in length and the receiver was an ex-Navy unit which covered
>> from 15 to 750kHz (B29?).
>>
>> 73 John G3PAI F5VLF
>>
>>> On 8 Aug 2018, at 17:49, DK7FC <selberdenken@posteo.de> wrote:
>>>
>>> Hello Genosse Roman,
>>>
>>> NAA should be centered exactly at 24 kHz, like DHO38 is at 23.4 kHz. It
>> can have strong QSB and appears only a few hours per day. Here it appears
>> arround 4 UTC these days.
>>> My grabber and all webpages do not work in the moment due to a webserver
>> problem which may be solved just next week...
>>> These narrow traces are something else, NAA always looks like DHO, about
>> 200 Hz wide.
>>>
>>> 73, Stefan
>>>
>>> Am 08.08.2018 14:15, schrieb Roman:
>>>> Hello Genossen VLFers!
>>>>
>>>> Pse, look R6LDD screen at russian forum.
>>>> What's a station? NAA or not?
>>>>
>>>> http://136.su/index.php?action="">
>>>>
>>>> The theme:
>>>>
>>>> http://136.su/index.php/topic,393.msg21804.html#msg21804
>>>>
>>>>
>>>
>>
>>
>>
--
73!
Roman, RW3ADB