http://hiraiso.crl.go.jp/wdc-c2/intro.html (PC Press Internet CD, 03/1996)

Introduction of WDC-C2 for Ionosphere

The Communications Research Laboratory(CRL), Ministry of Post & Telecommunications, operates the World Data Center(WDC) C2 for Ionosphere. The data corrected since 1957 at the center are:

Ionospheric vertical soundings
(ionograms of 6 Japanese stations from 1950 and about 100 stations worldwide from 1957; monthly tabulations for 220 stations worldwide from 1946)
Topside soundings,
Oblique incidence soundings,
Radio wave absorption,
Ionospheric Drifts,
Ionospheric backscatter,
Whistlers and VLF emissions,
Atmospheric radio noise,
Radio propagation predictions,
etc.

For further information, see "CATALOG OF DATA IN WORLD DATA CENTER C2 FOR IONOSPHERE" annually issued by Communications Research Laboratory. Copies of these data are available upon request with a standard charge plus postage. Prices of copying are as follows:

+-----------------+------------+-------+---------+-----------+
|  Original data  |  Copying   | Unit  |  Price  |  Remarks  |
+-----------------+------------+-------+---------+-----------+
|  Publication    |  Hard Copy | Sheet |  30 yen |  A-4, B-4 |
+-----------------+------------+-------+---------+-----------+
|  Ionogram       |  Film      | Feet  | 150 yen |           |
|                 +------------+-------+---------+-----------+
|                 |  Hard Copy | Sheet |  60 yen |  A-4      |
+-----------------+------------+-------+---------+-----------+
Note: Mailing or shipping costs may be added, depending
      on the size of the order.

Inquiry and requests should be sent to the following address.

WDC-C2 for Ionosphere
Communications Research Laboratory
2-1 Nukui-Kitamachi 4-chome
Koganei-shi, Tokyo 184, japan

Phone: 0423-27-7478, Facsimile: 0423-27-7606
(International Calls; Phone: +81-423-27-7478, Facsimle: +81-423-27-7606)
Cable Address: DEMPA KOKUBUNJI TOKYO
Telex: 2832611 DEMPA J