[sarex] Home work for ISS/SSTV fans.
ka1rrw at yahoo.com
Thu Jul 15 17:21:15 PDT 2010
ISS SSTV Home work:
Marex is always trying to improve our Manned space flight projects.
I could use your help in analyzing the images coming from ISS.
Here are a few homework assignments for you.
Assignment #1: WatchDog timer:
Try to video tape a full SSTV sequence from beginning to end.
We have heard rumors that the transmitter may be getting stuck “ON” after sending an image, and then later aborts in the Middle of the “Next” image when the built-in Watchdog timer activates.
Can you be the first to catch a full video sequence of this happening?
See if you can calculate the setting of the TM-D700 Watchdog timer.
Calculate Slide Show delay.
Try to record 2 or more images in a row. Record the start of each image.
If your images include the UTC time stamp you can also try to calculate if the clock on the laptop is set correctly (it may be on Russian time or UTC time).
The time between images, minus the image transmission time, will be the slide show delay time.
The original SpaceCam1 duty cycle goal was less than 40% transmitter time.
A Slide Show delay of 3 minutes, with Robot-36 would put the transmitter in this range.
The current images from ISS on July 15, are using Martin-1, which requires approximately 114 seconds per image.
The stuck transmitter VOX bug, keeps the radio running for up to 3 minutes at a time.
This means, that if we want to keep the transmitter duty cycle to 40% or less, we need to increase the Slide show mode to 8+ Minutes.
When you have your results, send them and supporting images to: marexmg at comcast.net
Rename your images and use the following format
I removed the first two numbers of the year and the “Z” for UTC time.
All dates are assumed to be in UTC dates. The images coming down from ISS using Marex SpaceCam1 will also have a time stamp embedded into the image. You can also use these numbers to generate you file names. If you are a Short Wave listener and do not have a call sign, just place your Initials after the time (0607311905abc.jpg)
If we break this down
Month = 07
Day = 31
Time = 1905 UTC
Call sign = wf1f
Description (optional) = Windows shot
Image format = JPG
Please do not put any text over lays on the images, Example, do not put web page or advertisements in the image. Your own call sign and date are acceptable.
Send all images directly to MAREX at
Marexmg at comcast.net
Thank you for your support
More information about the SAREX