"Wavescan" is a weekly program for long distance radio hobbyists produced by Dr. Adrian M. Peterson, Coordinator of International Relations for Adventist World Radio. AWR carries the program over many of its stations (including shortwave). Adrian Peterson is a highly regarded DXer and radio historian, and often includes features on radio history in his program. We are reproducing those features below, with Dr. Peterson's permission and assistance.
Wavescan 322, February 25, 2001
Japan on Shortwave during the Pacific War
Currently, half a dozen people associated with Pacific Radio Heritage in New Zealand are conducting long term research into the fascinating story of radio broadcasting in the areas of the Pacific and Asia during the Pacific War. This extensive research is uncovering a host of almost forgotten events regarding the radio scene in the Pacific and Asia back in the middle of the last century.
In this edition of Wavescan, we investigate the shortwave radio scene in Japan during the Pacific War. In subsequent programs at approximately monthly intervals, we will investigate the radio scene in other countries in these areas of Asia and the Pacific, incuding the change of call signs during this same era.
The first experimental radio broadcast in Japan went on the air from mediumwave station JOAK in Tokyo on March 1, 1925, and a regular radio service commenced just two weeks later. Five years later, in 1930, the first succesful broadcast on shortwave went on the air from a 20 kw communication transmitter located at Nazaki.
This experimental broadcast was a relay from mediumwave JOAK and it was beamed across the Pacific to Japanese communities in North America and Hawaii. Reception of these somewhat irregular broadcasts was confirmed with QSL-cards, printed in either Japanese or English.
A regular shortwave service was inaugurated on June 1, 1935 using this same 20 kw transmitter at Nazaki, which was on the air under a series of call signs in a three letter sequence beginning with "JV." Initially this was a one hour daily service in English and Japanese beamed to the same areas across the Pacific.
During the following year, 1936, an additional 50 kw transmitter was installed at Nazaki specifically for broadcast usage. This unit was on the air under a similar series of three letter call signs beginning with JZ.
As part of an expansion program, a new multi-storeyed building containing studios and offices was opened in Tokyo in May 1939, and two years later a new transmitter site was commissioned at Yamata, quite near to Nazaki.
As part of a fact-finding monitoring tour, NHK Radio Tokyo sent a senior engineer to Australia and Indonesia in September 1940. During his visit to Sydney, Engineer Chuhei Anazawa contacted the radio magazine "Australasian Radio World" and gained a report of the reception conditions of Radio Tokyo as heard in Australia. He was in Australia for just a couple of days, and on his return journey he made a similar visit to Batavia in the Dutch East Indies (or Jakarta, Indonesia as we know it today).
At the time when the Pacific War flared up at the end of 1941, Japan was on the air by shortwave with five transmitters at two locations. These transmitters were two at 20 kw and three at 50 kw, and the two locations were Nazaki and Yamata.
Program output at this time was also increased with the introduction of new services to various parts of Asia and the Pacific, and also with the introduction of new languages. Three years later, by the end of hostilities, Radio Tokyo was on the air with nearly 33 hours of programming daily in 24 languages.
The best-known programs at this time were the "Zero Hour" and the broadcasts of Tokyo Rose, both in English. Radio Tokyo also included Prisoner of War information in the broadcasts directed to Australia and New Zealand. They also broadcast programs in Japanese for their own armed forces on duty in various areas of the Pacific and Asia.
During this period of three and a half years, the scheduling of shortwave programs from Radio Tokyo was published in Australian radio journals, along with many monitoring reports. It was also reported that there were many technical interruptions to these transmissions due to the shortage of spare parts and skilled technicians.
Although all shortwave broadcasts from Japan ended in August 1945, yet they were on the air soon afterwards for a period of around three years for the benefit of Japanese prisoners of war in China. These broadcasts were in two sessions daily, using two transmitters on each occasion, 15 kw and 5 kw.
Time Line - Japanese Radio Stations
JOAK, NHK, Tokyo, Japan, MW, Mar 1 1925 1st experimental broadcast
JOAK, NHK, Tokyo, Japan, MW, Mar 22 1925 regular broadcasting
JVx, NHK, Nazaki, Japan, 20 kw SW, Oct 1930 1st exprerimental relay
JVx, NHK, Nazaki, Japan, 20 kw SW, Jun 1 1935 daily one hr. service launched
JZx, NHK, Nazaki, Japan, 50 kw SW, 1936 new transmiter installed
NHK, Tokyo, Japan, May 1939 new studio/office building
NHK, Yamata, Japan, SW, 1941 new transmitter base
NHK, Tokyo, Japan, SW, Sep 1940 engineer in Sydney, Batavia
NHK, Tokyo, Japan, SW, Dec 1941, two xmtrs at 20 kw, three at 50 kw
NHK, Tokyo, Japan, SW, Nov 1944, 32.5 hrs., 24 languages
NHK, Tokyo, Japan, SW, 1948-1951, POW broadcasts to China