IARU Amateur Satellite Frequency Coordination

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TeikyoSat-4 Updated: 24 Aug 2021   Responsible Operator Hirotoshi Kubota JQ1ZTA
Supporting Organisation Space System Society of Teikyo University  
Contact Person kubota@ase.teikyo-u.ac.jp.nospam  
Headline Details: Missions of TeikyoSat-4 are as follows: (1) Main Mission Purpose: To increase reliability of the communication systems by providing redundancies on transmitting/receiving systems and antenna configuration ・Communication System:The Main Mission is illustrated by blue-colored region in the Communication System Diagram (1) in website of Space System Society of Teikyo University, ・Frequency Plan : Teikyosat-4 wishes to use amateur radio band of VHF(145 –146 [MHz]) /UHF(435 – 438 [MHz]) for uplink/downlink. ・Reliability of Transmitting/Receiving Systems : The transmitting system TX and the receiving system RX consist of dual subsystems as (a) TX1: CW and AFSK on FM, (b) TX2: CW, AFSK on FM, GMSK on FM and SSTV (Slow Scan TeleVision), (c) RX1: AFSK on FM, (d) RX2: AFSK on FM, which provide redundancies to CW and AFSK for transmitting and AFSK for receiving. These will assure reliability of the communication, because it can be accomplished if either of (a) or (b), and (c) or (d) fail. It is based on the lessons learned of TeikyoSat-3 launched in 2014, whose communication system did not work completely because it had only one system of (a) and (c). For the above reason, TX1 and TX2 are of same frequency, and RX1 and RX2 are also same. ・Reliability of Antenna Performance : TeikyoSat- 4 applies a non-deployable antenna for TX2 and RX2 in contrast with a deployable antenna for TX1 and RX1 (see 4c and 4d, and website of Space System Society of Teikyo University, http://club.uccl.teikyo-u.ac.jp/~t_ushiken/ TS4HP/com.html). The reason of application of two kinds of antenna is to prove redundancy based on the facts as follows: (1) Deployable antenna such as monopole/dipole has high gain but it brings an essential concern on certain deployment, and (2) Non-deployable antenna has no concern of undeployment but there is few experience of using it for nano- satellite. Thus, the Main Mission has also a role of feasibility experiment of the non-deployable antennas of inverted L and inverted F. TeikyoSat-4 Team expects that radio amateurs join to receive the signals from the non- deployable antenna for advancement of radio technology. ・Contributions to Radio Technologies : TeikyoSat-4 Team will actively publish the information of the satellite such as transmit frequency, demodulation method and operation plans to enable the radio amateurs to receive the signals from the satellite directly, which promotes their interest for the amateur satellites. TeikyoSat-4 Team also will offer an opportunity  where many people can experience the fun of amateur radio activity in the event where children can receive the signals from the satellite by support of TeikyoSat-4 Team and radio amateurs at the Teikyo University Festival. (2) New Mission Purpose : To achieve the high-speed satellite communication system ・Communication System:The New Mission is illustrated by pink-colored region in the Communication System Diagram (1) in website of Space System Society of Teikyo University, http://club.uccl.teikyo-.ac.jp/~t_ushiken/TS4HP/ com.html ・Frequency Plan : Teikyosat-4 wishes to use amateur radio bands of 1.2 [GHz]/5.8 [GHz] for uplink/downlink for the purpose of technical verification of high-speed data transmission/ reception. ・Necessity of High Speed Communication : As TeikyoSat Project is necessary to transmit much data such as movie with more precise information to the ground in future, TeikyoSat-4 will try to construct a high speed communication system as well as more broad applications. The SHF band such as 5.8 [GHz] is not generally utilized, so that its application to communication system of TeikyoSat-4 is contributable to more utilization and activation of SHF band through advancement of satellite tracking technology and picture data acquisition together with many radio amateurs. Especially, it contributes to resolution of technical issues of tracking techniques and frequency shift as 5.8 [GHz] band having a strong directivity. ・Contributions to Radio Technologies : TeikyoSat-4 Team will release the above described technologies and experiences of high speed communication on website in order to inform to the radio amateurs. By utilizing a parabola antenna which will be constructed for 5.8 [GHz] downlink for TeikyoSat-4, it will be possible to perform “School Contact” using HAMTV as well that did in the past “ARISS School Contact”. Through the above two missions, based on the definition of amateur radio operation rule, Teikyosat-4 shall greatly contribute to advancement of amateur radio technologies and outreach to the radio communication activities. TeikyoSat-4 is a cubic-shaped nano-satellite with external dimensions of 455 [mm] x 455 [mm] x H450 [mm] and mass of approximately 50 [kg]. The satellite envelope volume is approximately 500 [mm] x 500 [mm] x H500 [mm]. Proposing UHF downlinks using CW, 1k2 AFSK, 9k6 GMSK and SSTV plus a 5.8 GHz downlink using 15k2 FSK. Uplinks will be on VHF, UHF and 1.2GHz. Planning a launch from Japan into a 600km SSO. **Downlinks on 437.450 MHz, 5831.000 MHz have been coordinated** **Now scheduled to launch on Epsilon 5 from Uchinour Space Center on October 1st 2021**
Application Date: 04 Jun 2017   Freq coordination completed on 27 Jun 2017

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