Kenwood Communication Support

The Kenwood Communication Corporation has been very supportive of the Russian Space Station Mir Amateur  radio projects.

The Kenwood Amateur radio products have been in use on the Mir station since 1996.

The SAFEX radio club of Germany upgraded the existing packet experiment on the Mir station by adding a new dual band radio transceiver to the Mir Space Station.  A Kenwood TM-733 radio (European version) was installed in 1996 and has been in continuos duty for the past 3 years.

The  Kenwood TM-733 is currently connected to the Mir Personal Message System.  The PMS, as it is called, is a simple 1200 baud packet system, which is used by the crew to send and receive mail messages from family and friends.  The system can also be used for voice contacts and has been used to make contact with dozens of schools and thousands of individuals around the world.

During the electrical problems with Mir in 1997, the Kenwood TM-733 was used extensively to pass family traffic between one of the crew members and his wife on a daily basis.

With the help of the Kenwood Corporation, the MAREX-MG club acquired 2 Kenwood TM-733 in 1997 to help support the Mir crews on station.  The MAREX-MG team was providing the primary support to crews in space, when ever the crew had a questions about the Amateur Radio Station, it seem to make sense to have a similar setup in our lab.The first week the TM-733s arrived at my lab, I got a call from NASA regarding a problem with the TM-733.  It seems that the radio was inadvertently placed in LOCK mode.  The crew could not use the radio for any voice or packet contacts.  The Mir crew could not find the Manual, and they wanted the key sequence to clear the LOCK mode.  Within a few minutes of receiving the call, I gave the correct key sequence to the NASA engineer.  The information was then passed through channels back up to the Mir station. Within 24 hours the Mir crew got the information and was on the air chatting with people from around the world.

The Kenwood TM-733 lab system was also used extensively in debugging interference problems on Mir. One Astronaut once said, there are more transmitters in Mir than any place I have ever seen”. When you put a bunch on transmitters in very close proximity, you are bound to get some interference.

The Amateur Radio station was being interfered with by one of the commercial transmitters operating in the 143 MHz portion of the band. When the 143 MHz transmitter was active, the 2-meter receiver listening on 145.200 would go temporality deaf. The fix was a two part solution: First, move the 2-meter receive frequency as far away as possible from the commercial transmitter (within guidelines of the ITU radio rules). The 2-meter Mir receive frequency was moved from 145.200 to 145.985 FM Simplex.

This partially solved the problem. If you were transmitting 1000 watts of ERP, the Mir 2-meter receiver could hear you while the 143 MHz transmitter was on. To allow weak signals to be heard while the commercial transmitter was active, the MAREX-MG team contracted with DCI filters to custom build a cavity filter which would block the interfering signal and pass only 2-meter signals.

The MAREX-MG team tested the filter against the labs Kenwood TM-733 and verified the inference was gone. The SAREX team flight qualified the DCI filter, which was delivered to the Mir station in December 1997 by Progress Cargo rocket TM-37.

The second TM-733 was sent to Houston Texas, to be used as a training tool for future Astronaut hams.The Kenwood TM-733 was also used to help answer questions about which channels should be used in space for future manned space missions. One of the satellite Amateur Radio committees tired to find a new world wide frequency for the Space Station Mir. A frequency suggestion which would work in one part of the world, may be the busiest channel in an another part of the world.

One of the frequencies proposed by the committee was 144.490 uplink, with a 145.812.5 MHZ down link. The 145.812.5 frequency is a 12.5 channel step. The 144.490 channel is a 5 or 10k channel step.

MAREX-MG insisted that the channel be tested, before we tell the crew about the change. After a quick test with the Kenwood TM-733, it was discovered that you can not mix a 10k channel step with a 12.5k channel step. In fact, almost all 2-meter radio in the market today can not save that specific odd split into a memory location. Fortunately the problem was found on the ground and no crew time was wasted.

Since the current frequency of 145.985 Simplex has been so successful, it has been deiced to keep the station on this frequency for the remainder of its mission.

The Kenwood transceivers were also chosen for the next Mir project.

MAREX-MG contracted with Energia to build a Slow Scan Televisions system for the Russian Space Station Mir. The SSTV system, will send 720 snap shot images to earth every day. For more information about the SSTV system, check out the MAREX-MG web page at: http://www.geocities.com/CapeCanaveral/Hangar/7355/sstv_proj.htm.

A Kenwood TM-V7A transceiver was chosen to be the radio for this system. Four complete SSTV systems were built. Three systems are currently in Russia at Energia awaiting a flight opportunity. No specific launch date has been given at this time.

These are just a few examples of the advanced work which MAREX-MG and Kenwood have been performing to ensure world-wide inexpensive Amateur Radio satellite access to everyone.

Note:The MIREX (Mir International Amateur Radio Experiment) club split into two clubs with different duties in May 1998 (MIREX and MAREX-MG). The MIREX club handles QSL cards and some system-operator duties. The MAREX-MG club builds and flies Amateur Radio projects for the Russian Space Station Mir and is also proposing similar projects for the International Space Station.

To date, MAREX-MG has delivered two Amateur Radio projects to Mir, and has a third project pending delivery to Mir in the fall of 1998.

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