"And if the ISS Air pressure is turned down from 14 psi to 10 psi [Usually during space walks], the radio will also run hotter at 10 psi, than at 14 psi." - I thought if there was a spacewalk ALL amateur radio transmissions would be turned off.


On Mon, Jul 19, 2021 at 1:14 PM GMM via AMSAT-BB <amsat-bb@amsat.org> wrote:

Best Project first:

If you have multiple projects and limited resources, you need to choose the project that will be the most successful or Get the best bang for the buck.

What are you goals for an Amateur-Radio project for ISS?


#1, Generate interest in Amateur radio capabilities.

#2, Encourage Non-Amateur-radio people to possibly get-into the Amateur-Radio or SWL Hobby.

#3, Get more people excited about the ISS and is open programs that can allow the average person to participate.

#4, Provide the ISS crew with some entertaining and excitement about their projects.

#5, Language universal projects work best.


The APRS project has a low following and does not generate much excitement or newspaper coverage.


SSTV does great and all 5 of the listed categories.


Why is SSTV better the APRS?


SSTV is a project that will cross over between two hobbies,  Short-wave-listening and Amateur radio.  Most Short-wave-listening and Amateur operators are capable of receiving and decoding SSTV signals.

With 10's of millions of SWL+AR stations receiving these signals month after month, you will see a huge interest in the abilities of Amateur Radio on ISS.

You must have heard the saying "A picture is worth a thousand words".

When MarexMG was running the SSTV Program in Space Station Mir, out SSTV images were showing up in magazines and newspapers around the world.

When was the last time you saw a New paper or magazine story [Non-ham] talking about APRS from ISS?  Never!

The MarexMG SSTV project was a huge hit.  Schools around the world were setting up receiving stations to receive the images.  I remember seeing a new story showing how the Great-Lakes ices was changing week after week, based on images from Mir SSTV.

 If we want to build up a large amount of support for existing and future Amateur radio projects on ISS, then we need to put our best project front and center.

I am not talking about turning on SSTV for 1 or two weekend per year.

I am talking about turning it on for a FULL 6 consecutive months in a row 24 hours a day, 7-days a week.


Image cycle duration:


Let's keep is Simple and Safe.

Recommended format:

To provide the greatest access and reduce Heat stress on the radio, I recommend using SSTV format Robot-36.

The reason for the low-quality Robot-36, is because the transmitting time is only about 36 seconds for each image.  I know this is the lowest quality image format, but since it’s the shortest, we can keep the radio cooler. 

All transmitters run MUCH hotter in Zero Gravity! 

And if the ISS Air pressure is turned down from 14 psi to 10 psi [Usually during space walks], the radio will also run hotter at 10 psi, than at 14 psi.

Maximum number of ISS-transmitted images per hour.

1 image every 5 minutes or 20 per hour.  And depending on heatsink temperature and cooling fan status, we may need to reduce the number of pictures per hour to keep the radio cool.

My goal is to expand the presence of Amateur Radio on ISS and other satellites and the best tools we have on ISS today is Slow Scan TV.


Let's generate some worldwide excitement and make this hobby grow.

Turn off APRS!

Turn ON SSTV for a FULL 6 consecutive months in a row 24 hours a day, 7-days a week.

And then start watch the publicly generated by Marex SPACE-CAM1

by Miles, WF1F 


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