The Shimoizumi log-periodics, continued

Original: Ryota / JJ1WTL — 519392776 · Original Japanese HTML

Published: 2025-12-04T21:19:00+09:00

English translation of the archived article text. The author’s first-person observations, uncertainty and later additions are preserved; this is not the research summary. Image contents are preserved as images, not silently incorporated into the translated prose.

Following the Radio Station Information Search update at 06:16 on Thursday, December 4, I am adding another experimental HF digital fixed station, bottom row below.

Image 1: 20251204mjk-ex-chiba.jpg

Here it is

In satellite imagery

Google Earth imagery photographed February 20, 2025 shows the site after grading:

https://earth.google.com/web/@35.42350004,140.03725558,57.68661258a,198.27096587d,35y,0h,0t,0r/data=ChYqEAgBEgoyMDI1LTAyLTIwGAFCAggBOgMKATBCAggASg0I____________ARAA?authuser=0

In the Radio Station Information Search

https://www.tele.soumu.go.jp/musen/SearchServlet?pageID=4&IT=A&DFCD=0004603382&DD=1&styleNumber=21

Copied below, with boundaries shown in the emission/frequency/power section to clarify the divisions.

The callsign is not disclosed at present.

I will add it and retitle the article once it is published.

Licensee: Ermis K.K. Licensee address: *****. Station category: experimental station. Licence number: *****. Licence issued: December 1, 2025. Valid until March 31, 2027. Purpose: experiments and tests. Permitted operating hours: continuous. Communications: matters relating to experiments, tests or investigations, excluding Argos-system data transmission and education. Correspondents: receiving equipment belonging to the licensee near Johor Bahru, Malaysia, and near Manhattan, USA. Identification signal: *****. Installation location or operating area: Sodegaura City, Chiba Prefecture. Emission class: 12K0G1D. Frequencies: 9081, 9126, 10845, 10953, 12117, 12159, 14673, 14736, 16119, 16209 kHz. Antenna power: 4 kW. Remarks: blank.

Thoughts

They have excluded frequencies below 7 MHz from the outset.
Johor Bahru is effectively 9V [Singapore].
This is the first company targeting W2 [New York area].

[Translator's note: W2 is Ryota's interpretation here. The project's subsequent ITU analysis places the declared counterpart at Manhattan, Illinois; the original claim is retained.]

AS 41694

The company has also obtained an autonomous-system number.

https://www.peeringdb.com/net/25828

Already multihomed:

AT TOKYO CC1/CC2, Toyosu.
MC Digital Realty NRT10, Inzai.

‘Sodegaura ↔ microwave ↔ Toyosu ↔ fibre ↔ Inzai’

—perhaps that is the arrangement.

There is a microwave fixed-station licence for Sodegaura–Toyosu:

Image 3: 20250705mjk.jpg

https://www.tele.soumu.go.jp/musen/SearchServlet?pageID=4&IT=A&DFCD=0004609338&DD=1&styleNumber=21

https://www.tele.soumu.go.jp/musen/SearchServlet?pageID=4&IT=A&DFCD=0004609339&DD=1&styleNumber=21

Impressive to cover everything from wireless to wired, and Layer 1 through Layer 3.

They do not look like a company to underestimate.

Comparing all stations

An update to the table in the earlier article ‘JB2XI’: https://jj1wtl.seesaa.net/article/505733007.html (English translation)

Field	JS2RA	JS2RB	JS2SA	JB2XH	JS2SB	JB2XI	*****
Operator	DATACOM SERVICES	DATACOM SERVICES	4HF	High Bar Communications	Sora Communications	GT Technologies	Ermis
Location	Kubota, Sodegaura City	Kubota, Sodegaura City	Cosmo Classic Club, Minamiboso City	TX: Kawado, Chikura-cho, Point 120 m RX: Gotenyama / Takatoriyama	Kokubo, Futtsu City	Cosmo Classic Club, Minamiboso City	TX: Shimoizumi, Sodegaura City RX: Maeda, Minamiboso City
Licence issued	2021-09-15 → 2024-01-01*	2023-01-25 → 2024-01-01*	2023-06-07 → 2024-01-01*	2023-07-28 → 2024-01-01*	2024-10-22	2025-06-16	2025-12-01
Valid until	2023-12-31 → 2027-03-31*	2023-12-31 → 2027-03-31*	2023-12-31 → 2027-03-31*	2023-12-31 → 2027-03-31*	2027-03-31	2027-03-31	2027-03-31
Counterparts	Chicago, USA	Philippines	Chicago, USA; Singapore; London, UK	Johor Bahru, Malaysia; Chicago, USA†; London, UK†	Near Hong Kong; Batam, Indonesia; Johor, Malaysia	Near Johor, Malaysia	Near Johor Bahru, Malaysia; Manhattan, USA
Emission			12K0A1D		10K0A1D
Emission	12K0D1D	12K0D1D	12K0D1D		10K0D1D, 10K0D7D	12K0D1D
Emission				12K0F1D	10K0F1D, 10K0F7D	12K0F1D
Emission	12K0G1D	12K0G1D	12K0G1D	12K0G1D	10K0G1D, 10K0G7D	12K0G1D	12K0G1D
Emission			12K0K1D
Frequency (kHz)	6864	6864	6864**	6864**	6864
Frequency (kHz)	6900		6900	6900	6900
Frequency (kHz)	9081	9081	9081**	9081**	9081	9081	9081
Frequency (kHz)	9126		9126	9126	9126	9126	9126
Frequency (kHz)	10845	10845	10845**	10845**	10845	10845	10845
Frequency (kHz)	10953		10953	10953	10953	10953	10953
Frequency (kHz)	12117	12117	12117**	12117**	12117	12117	12117
Frequency (kHz)	12159		12159	12159	12159	12159	12159
Frequency (kHz)	14673	14673	14673**	14673**	14673	14673	14673
Frequency (kHz)	14736		14736	14736	14736	14736	14736
Frequency (kHz)	16119	16119	16119**	16119**	16119	16119	16119
Frequency (kHz)	16209		16209	16209	16209	16209	16209
Antenna power	10 kW	5 kW	3 kW	10 kW → 1.5 kW††	8 kW, 8 kW	2 kW	4 kW
Antennas***	7-element low-band upper array; 10-element high-band middle array	7-element low-band upper array; 10-element high-band middle array; 5-element Yagi below on JS2RA's tower	5-element Yagi	TX: 13 elements on three towers; RX: 13 elements	Two ten-element arrays on each of two towers	10 elements	TX: twelve elements on each of two towers; RX: two rows of eight loops