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Special Article

The world of 5.6 GHz enthusiasts.
The current state of the 5.6 GHz band and how to enjoy it.

Editorial section of the Monthly FB NEWS magazine

The normal method of SHF communication is usually on a scheduled basis in a group using FM and/or D-ATV (Digital Amateur Television). The group also meets from time to time to exchange information on each other's radio equipment and to conduct experimental communications in portable operations.

Before Mr. Kaneko’s attempting a portable operation, he uses a simulation software to check the line-of-sight range and direction of the other station on a map. Of course, he checks the output frequency and power of the transverter before going out to the place of operation. Recently, by using the Icom IC-705 as an IF radio, he has been able to find the other station visually with a spectrum scope on the IC-705 screen, even in this band where the other station tends to be off frequency.

JA1OGZ’s team attempting to communicate with JA0RUZ. (Distance: Approx. 90 km)

JA1QHQ, Mr. Ehara (Left), JA7JJN, Mr. Yanagisawa (Right), targeting a mobile station from the top of a mountain 870 m above sea level.

JA7JJN, Mr. Yanagisawa (Left) JA1QHQ, Mr. Ehara (Right)

JA7JJN, Mr. Yanagisawa is pointing its antenna at a station moving toward Mt. Fuji.

As for mobile operation, there are four stations in his group including Mr. Kaneko. In addition to mobile operations, he sometimes communicates with mobile stations that are moving from his house by following their antennas. When his transmitting signal is weaker than the other station, he suddenly gets an energized to beat the other station signal and improve his own station performance. He sometimes experiences various propagation by following and communicating with mobile stations from his home. (For details, see Propagation below).

During a contest, he can receive about 40 stations in the 5.6 GHz band when he moves to a mountain in an area around Tokyo, and about a dozen stations can be received even in his home station, and the number of stations increases about three times more than usual. In Japan, there is the "6m AND DOWN Contest" which aims to improve operational activities in the VHF, UHF and SHF bands above the 50 MHz band. This contest is one of the most popular contests in Japan, as various anomalous propagation such as Sporadic E can lead to unexpected communication with distant stations.

Since the bandwidth of the 5.6 GHz band in Japan is as wide as 200 MHz, there is no interference at all for voice communications, and therefore D-ATV operations using the wide band (6 MHz) are also in active. The image data communication system has changed from FM-TV to DVB-S to ISDB-T (partially DVB-S2), and now the ISDB-T system, which is the same as general digital terrestrial broadcasting, is commonly used.

I show some actual image data received with the D-ATV system provided by Mr. Kaneko. Mr. Kaneko's communication partners were Mr. Sekizaki (JA0RUZ) and Mr. Tamagawa (JH1AOY). Mr. Sekizaki is a pioneer of ISDB-T and has been actively moving to higher ground to operate it. When I saw the actual communications with his friends, the image data and sound quality were the same as that of ordinary terrestrial digital broadcasting, and when I first saw it, I thought it was the image data of the transmission side that had already been recorded.

JA0RUZ transmits on D-ATV toward area in Niigata pref. (Distance: Approx. 110 km)

JA0RUZ transmits on D-ATV and JA1OGZ receives the image. (Distance: Approx. 115 km)

JA0RUZ transmits D-ATV image at Mt. Fuji and JH1AOY receives the image at Chiba Pref. (Distance: 105 km)

JH1AOY transmits image data and JA1OGZ receives that image at the fifth station of Mt. Fuji. (Distance: Approx. 105 km)

There are also amateur satellites that use the 5.6 GHz band that are scheduled for launch within the next one to two years. One is the Kyushu Institute of Technology's “KITSUNE” nano-satellite, which plans to send out CW beacons and packet data at 5840 MHz. Another is Nihon University's nano-satellite “Ten-Koh 2,” which is also scheduled to send out CW beacons at 5839 MHz. The signals from these satellites can be captured by a parabolic antenna of about 50 cm in diameter, and future operations are expected.

Although further down the road, the Lunar Orbital Platform-Gateway project is also being planned and I have heard that a transponder used with 5.6 GHz Up/10 GHz Down will be prepared as an Amateur Radio Transponder. Currently, a satellite using microwaves is equipped with a 2.4 GHz Up/10 GHz Down for amateur radio transponder on QATAR's geostationary satellite Es' Hailsat (QO-100), which is in geosynchronous orbit over the African continent. Unfortunately, Japan is out of the QO-100 coverage area, but Thailand and west of Malaysia are in its coverage area.

Parabolic antenna for 2.4 GHz/10 GHz for QO-100 made by Mr. Kaneko

The 5.6 GHz band is allowed to be used as a secondary use for amateur radio in Japan. Main uses are ISM band (for industrial science and medical), wireless LAN, FPV (system for remote control), and DSRC (ETC, VICS ETC 2.0), but it will also be used for indoor wireless power transmission in the future. Operation in the 5.6 GHz band is likely to have less impact on primary operations than the 2.4 GHz band if the location and time are chosen.

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