How to access the ISS Slow Scan TV

How to be successful with the ISS Slow Scan Television (SSTV) imaging system

By Miles Mann, WF1F MarexMG for the ARISS-International Team

The ARISS team has approved two SSTV projects for ISS. The SpaceCam1 project is currently on ISS. The SpaceCam1 project was tested in August 2006 and we are just waiting for a dedicated laptop for regular activation.

There is also a new SSTV project planed for launch in during Richard Garriott’s Soyuz Mission in Oct of 2008. There are tentative plans for Richard to take a Kenwood Visual Communicator VC-H1 SSTV unit with him on this flight.

For additional information on Richards Garriott’s mission on October 12, please review the following links:

http://www.richardinspace.com/

http://www.challenger.org/

SSTV Goals:

The goal of this series of memos is to get the Amateur Radio and Short-wave listener community ready to start decoding SSTV images from the International Space Station. If you want to get ready for SpaceCam1 and VC-H1 Slow Scan TV, then now is the time to start setting up your systems.

Slow Scan TV on the International Space Station:

The ISS SSTV system will support two-way SSTV image transmission. The SSTV systems will be used to send JPG images to and from Earth by Amateur Radio. Amateur Radio operators have been using SSTV since the 1950’s. Today there are many software applications available that will allow you to connect your home computer to a radio and allow you to decode images from space.

Actual SSTV images from Mir and ISS

Actual SSTV pictures received from Space Station Mir in 1998

Window shot from MIR

Gennady and Sergei Reading the Manual for the Kenwood TM-V7A, which was part of the Marex SSTV package.

Actual SpaceCam1 SSTV Images from ISS

Commander Pavel at the Amateur Radio station on ISS

Typhoon Saomai Western Pacific August 2006

The Basics of SSTV:

The SSTV system on the International Space Station that I will be focusing on is called SpaceCam1. The VC-H1 Project may be activated first, however their functionally is very similar and I will include additional information on the ARISS-VCH1 project as it becomes available.

The SpaceCam1 project is PC based application that is currently on board ISS and was tested from ISS in August 2006 (Add LINK). The SSTV system will be connected to an Amateur Radio transceiver called the Kenwood TM-D700. This radio will transmit on the Amateur radio 2-meter satellite band from the ISS. The ISS is tentatively planned to transmit SSTV (Down link) on 145.800 FM. The Uplink frequency has not been published at this time.

The transmission mode will be FM (approximately 4k deviation). The SSTV Image format used is called Robot-36 (Both SpaceCam1 and the VC-H1 will use the same formats). When SSTV becomes operational, it will be able to transmit over 300 images per day from the International Space Station. The crew will either load a disk directory full of still images taken earlier or enable the live still image camera.

The SpaceCam slide show will be configured for a specific delay between images. Let’s assume the delay is set for minimum of 3 minutes. The Space Station will pass within radio range of your house 4 to 6 times a day for up to 10 minutes per pass. During a typical 10-minute window you will have the opportunity to receive 2-3 images per pass. The typical Amateur radio station on Earth using a simple outdoor antenna will able to receive up to 18 images per day.

The Kenwood VC-H1 has a similar automatic live image transmitter. The VC-H1 will snap 1 live image every three minutes and then transmit the image down to Earth. We can expect up to 15+ images per hour. The system will most likely only be operated while the crew is awake and will probably be shutdown during the crews sleeping hours and during periods of orbital night.

VC-H1 & Kenwood TM-D700 System:

The VC-H1 will be connected directly to the Kenwood TM-D700 transceiver which is currently installed on board the ISS.

The typical transmitter power output for this system is 5, 10 or 25 watts. For the SSTV mode the transmitter power will be set to either the 5 or 10 watt setting. The 5 watt signal will be more than enough for most common ground antenna receiver combinations.

Kenwood Visual Communicator VC-H1

SpaceCam1 & Kenwood D700 System:

The Kenwood D700 transceiver is a versatile radio that supports voice and has a built in Packet modem which can be used for Email type messages. The D700 can also be connected to a computer and support other modes such as PC base SSTV or the VC-H1 can be directly plugged into the Microphone port. The D700 system is located in the Service Module. The D700 supports two Amateur radio bands: 2-meter FM (144 – 146 MHz) and the 70-centimeter FM (435 - 438 MHz). The built-in modem or TNC supports 1200 and 9600 baud data rates. The D700 is currently connected to one of the 4 Amateur Radio antennas mounted outside of the Service Module. The typical power output of this system is 5, 10 or 25 watts. The Kenwood D700 system was activated in December 2003. The D700 is the primary radio for all Amateur Radio Voce and SSTV projects. The ISS crew will connect the D700 to a laptop computer via a custom designed adapter module made by ARISS. The VOX-Box will match the audio signals from the laptop computer to the D700 radio. The VOX-box will also signal the radio when it is time to transmit.

What do I need at home to receive SSTV signal from ISS?

To work ISS from your home, you should have at least the following Amateur Radio equipment:

Note: most of the time the ISS SSTV system will be in down link mode only. ARISS has not published an uplink frequency or schedule at this time.

A 2-meter FM radio with an output rating of 25 to 50 watts or
A good quality FM receiver or Scanner that supports standard FM 5k.
An outdoor Omni-directional antenna or small beam (the higher the gain the better).
A short run of good quality coax (RG-213, 100 feet or less).
A PC running one of the common Slow Scan TV decoding applications.

And that is it for radio equipment. I use an inexpensive Laptop computer with a 233 MHz CPU and Windows 2000. The software I use is either CPIX by Silicon Pixels or and engineering version of SpaceCam1.

If you are a short wave listener, then you can use one of the many police scanners or similar receivers that support standard FM (5k deviation). The secret to good reception is a good outdoor antenna and good quality coax. You will not have much luck with an indoor antenna or a rubber-duck.

Slow Scan TV Decoding Software

Here are just two of the many Share-Ware SSTV applications on the market. There may be many more.

W95SSTV by Silicon Pixels

http://www.barberdsp.com/w95sstv/w95dload.htm

MMSSTV

http://mmhamsoft.ham-radio.ch/

There are also many High quality pay software applications that offer many more features, such as multiple windows that allow your to simultaneously receive an image while preparing your next image that you want to transmit.

CPIX

http://www.barberdsp.com/

When will ISS be in Range of my House (Timing):

You will need access to a computer or the web to tell you when ISS is in range of your station. The timing of your contact is the most important part of a successful contact with ISS. There are many tracking programs out in the market place today. The ARISS team does not endorse any specific tracking program. Some programs are share-ware (STSPLUS); others cost a few bucks. I recommend using the DOS InstantTrack, program by AMSAT. www.amsat.org This program is very easy to use and works very well with older style computers such as 80286 style PC's. The cost of most tracking software applications is approximately $50-100.

There are also many live web applications that you can use to track the position of ISS. I will often use the NASA web link to find ISS

http://spaceflight.nasa.gov/realdata/tracking/index.html

After you have found the orbital pattern for ISS you can just simply leave your SSTV application running in Automatic Receive mode and just let it run. That is one of the nice features of SSTV, you do not have to be sitting at the radio the whole time. Once you have worked out the bugs in your setup, and you know you are on the correct frequency you can just let it decode and save the images for you automatically.

Doppler Shift:

The ISS Space Station is traveling around the Earth at over 17,500-mph (28,000 Kph). The speed of the Space Station will make radio signals appear to shift in frequency. This phenomenon is called Doppler Shift. Many of us have radios that are Channel locked. This means you cannot make any fine tuning adjustments to your receiver or transmitter's frequency. Most Mobile and HT radios cannot make any frequency changes less than 5 kHz channel steps (lets hope that radio manufacturers will add 1 or 2 kHz channels steps in the future).

The Doppler shift will cause the ISS transmit frequency 145.800.0 MHz to look as if it is on the frequency 145.803.5 when ISS is approaching your location (approximately 3.5 kHz higher if frequency). Fortunately we will be using the FM mode which automatically compensates for part of the Doppler frequency drift. If you are fortunate enough to have a radio with the ability to make smaller channels steps then you should take advantage of this feature. You will need to review the owner's manual for your radio to learn how to program "Odd-Splits" channel combinations and program the following consecutive frequencies into your radios' memories.

If your radio is one of the more common radios that can not make the fine tuning steps, then do not worry, most of the time frequency error will be small enough for your radio to work fine.

For 5 kHz channel step radios do not try to adjust for Doppler.

( Region 2--North & South America, Region 3Asia, Australia )

Channel 1 145.800.0 RX SSTV no uplink

Channel 2 145.800.0 RX 144.490.0 TX Voice

Channel 3 145.800.0 RX 145.990.0 TX Packet (Worldwide)

Channel 4 145.800.0 RX 145.200.0 TX Voice (Region 1Europe, Africa )

For SSTV 2.5 kHz channel step radios (Worldwide)

Channel 5 145.802.5 RX

Channel 6 145.800.0 RX

Channel 7 145.797.5 RX

For VOICE (Region 2North & South America, Region 3Asia, Australia )

2.5 kHz channel step radios

Channel 1 145.802.5 RX 144.487.5 TX

Channel 2 145.800.0 RX 144.490.0 TX

Channel 3 145.797.5 RX 144.492.5 TX

For Packet 2.5 kHz channel step radios (Worldwide)

Channel 4 145.802.5 RX 145.987.5 TX

Channel 5 145.800.0 RX 145.990.0 TX

Channel 6 145.797.5 RX 145.992.5 TX

For VOICE (Region 1Europe, Africa) 2.5 kHz channel step radios

Channel 7 145.802.5 RX 145.197.5 TX

Channel 8 145.800.0 RX 145.200.0 TX

Channel 9 145.797.5 RX 145.202.5 TX

Let's assume ISS is approaching your location (QTH) and the SSTV system is active. Use channel #5 at the beginning of the pass, then when ISS is over head, use channel #6 and when ISS passes your QTH use channel #7. For best results, use an updated tracking program, which displays the current Doppler shift. This will assist you in determining when it is best to change channels.

As you may have noticed, it is not recommended for you to adjust your uplink frequency on 5 kHz radios. You may have better results if you leave your receiver on 145.800 and your transmitter on 145.990. The Doppler shift is only at the +3.5 kHz setting for a few seconds, then it will slowly begin to approach zero. After 5 minutes or less, the Doppler shift will be 0 for a few seconds, and then it will begin to swing towards -3.5 kHz.

What is Slow Scan TV:

On this web page you will find many links to help you learn more about SSTV

http://www.marexmg.org/fileshtml/sstvlinkpage.html

Practice Practice Practice:

If you want to be successful in sending and receiving SSTV from ISS you must be fully proficient in using SSTV on Earth first, before you make any attempt to use the SSTV on ISS.

If you can not find any friend locally to test with on 2-meter, you can always try 20-meter (14.230 USB, assuming you have license privileges and equipment). During most of day and night you can easily hear people sending SSTV images on the 20-meter band. On HF the most common SSTV analog mode is called Scotty-1. Most SSTV applications support several of the common SSTV modes.

Receiving Images from Space:

The Kenwood VC-H1 and SpaceCam projects will allow both uploading and down loading of images from ISS, however it is expected that most of the time the systems will be in downloading mode only. For now you will just need to concentrate on receiving SSTV images from space.

Picking A Pass:

Use your computer program to select a good pass with high elevation angles. When ISS first appears on the horizon, the satellite will be 1500 miles (2400 km) away. When ISS is directly over your house, it is only 240 miles (384 km) away.

Using your tracking program, pick a pass with a maximum elevation of over 40 degrees. These are typically the best passes because ISS will be closer to your QTH. For low elevation angles, your radio signal will have to travel along the ground, where it will be affected by trees, buildings and hills. When ISS is high above the trees, you will have a clear line-of-site shot to the ISS antenna. A 1000-mile contact on 2-meters is easy, that is if there is nothing between you and the other station. A good pass is only 10 minutes long.

Don’t wait to try SSTV:

As more information becomes available on the activation dates of the project, the information will be posted Don’t wait until the last minute to get your home station SSTV ready.

73 Miles WF1F MAREX-MG

Until we meet again

DOSVIDANIYA Miles WF1F

You are visitor # since September 2008

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