Decoding SSTV from ISS

Forum for discussion of SSTV topics. Slow Scan television (SSTV) is a picture transmission method used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or colour.

Moderators: Dave Moll, Andrew Davie, Steve Anderson

Decoding SSTV from ISS

Postby acl » Tue Oct 05, 2021 6:25 am

https://www.esa.int/ESA_Multimedia/Vide ... ce_Station



And I thought you needed a receiver and funny Ariel
acl
Anyone have a spare straightjacket?
 
Posts: 448
Joined: Thu Mar 08, 2007 7:38 am

Re: Decoding SSTV from ISS

Postby Klaas Robers » Tue Oct 05, 2021 9:00 pm

Have you seen how many things you should do before you get your picture(s)? Then it would have been much easier if ISS uploads their pictures as a .jpg to the internet en give you just a URL (internet address). Here all the interesting things are hidden in the smartphone and you just have to click on the apps. That is not where SSTV is developped for.
User avatar
Klaas Robers
"Gomez!", "Oh Morticia."
 
Posts: 1656
Joined: Wed Jan 24, 2007 8:42 pm
Location: Valkenswaard, the Netherlands

Re: Decoding SSTV from ISS

Postby Steve Anderson » Tue Oct 05, 2021 10:08 pm

I tend to agree with Klaas, it's not my understanding of what Cop McDonald intended, but one could view it as a development, an outgrowth. At first we had CW, then AM, then FM, then SSB for voice/message modes (the order may be wrong), and later maybe other modes too.

So too the evolution of SSTV. It's only natural that users would prefer higher resolution and full colour. However I would 'in a way' align myself with those few still interested with 405-line (or other) monochrome TV standards (includes NBTV, otherwise why would we be here?). In that I like the old 120/128-line standards. It started in (approximately) 1959 and in my opinion is still relevant today. 7.2s or 8s for an image as opposed to minutes? Give me the former. But everyone is different.

Before I first ever saw 7.2/8 second SSTV I thought, "that's far too long." But surprisingly it's not. It passes really quick, certainly faster than 2+ minutes...I'm not a generally impatient guy, but waiting for minutes for an image, no thanks. And there's always the chance the link craps out on you and you never get it anyway.

So although the PD120 mode and others the like are an 'advancement', I'll stay in my little outdated corner if you don't mind...

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 5376
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: Decoding SSTV from ISS

Postby kd2bd » Wed Oct 06, 2021 2:33 am

My interest in SSTV goes back over 40 years when the monochrome 120/128 line format was the universal standard. A few years later I got my ham license, but my homebuilt P7 equipment had become obsolete in those few short years. Computer-driven SSTV never appealled to me, and while my interest in SSTV drove me to get my ham license, I have never had an SSTV QSO.

However, I *am* interested in satellite communications, and so I am occasionally driven to tune into the ISS during their SSTV events. The last one was in August, and for the first time I used a smartphone held against the speaker of a 2-meter handheld for reception. There's a ghost in the images, possibly due to my method of acoustic coupling between the receiver and the phone.

This simple and portable arrangement is good for "impressing your friends" and perhaps sparking some interest in space and communications technology, but probably not much else. The images I received can be seen below. Not only does it require 2 minutes to transmit each image, but there is a 2 minute gap between each transmission to allow the transmitter to cool down. (Heat doesn't rise in a zero-G environment.) The ISS dropped below my horizon before the completion of the third image.

73 de John, KD2BD

iss_sstv.png
User avatar
kd2bd
Mad Scientist
 
Posts: 65
Joined: Wed Sep 28, 2016 5:47 am
Location: New Jersey

My most treasured QSL card

Postby acl » Wed Oct 06, 2021 6:55 am

This card was sent to me when I posted off images from Challenger spacecraft decoded on my Sinclair Spectrum 48 printed on silver printer paper. Using a handheld two metre rig and motorised rotating Yagi



1.jpeg

3 1.jpeg

3.jpeg
acl
Anyone have a spare straightjacket?
 
Posts: 448
Joined: Thu Mar 08, 2007 7:38 am

Re: Decoding SSTV from ISS

Postby Steve Anderson » Wed Oct 06, 2021 12:22 pm

Well done guys! Not having any means of receiving 2m I'm in the dark, literally! If a 2m receiver kit were available (QRP Labs - a hint!) I'd have a go. I don't have the experience to design one from scratch. HF/VHF receivers are a bit of a 'black art' to me. Transmitters - no problem - they were a large part of my career in broadcasting, though mostly VHF/UHF and at vastly higher powers than amateurs are allowed...500kW PEP (Peak Envelope Power) for an analogue TV transmitter was not unusual (note the past tense).

A kit also makes sourcing parts easy - I wouldn't know where to get 10.7MHz IF filters/transformers from, though probably not that hard to find from specialist suppliers.

For the HF bands I don't have the space for a HF antenna, I know there are 'compact' versions, but living in the middle of Bangkok I can only imagine the interference levels! So unless I move to a rural location it's probably not worth the effort anyway. There's also a 2kW AM transmitter on around 600kHz only 2km south of here. It occasionally breaks into stuff I build so I have to take remedial action to suppress it.

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 5376
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: Decoding SSTV from ISS

Postby kd2bd » Thu Oct 07, 2021 3:15 am

Chris,

I have the same QSL card. I still have audio recordings from that mission, and will someday process them through my scan converter to get a better look.

Back in August 1985, I used a homebuilt copy of a Robot 70A SSTV monitor feeding an old oscilloscope with a 5UP7 CRT as a display device. I made some time exposure photographs of my reception by focusing the light from the CRT on some Polaroid SX-70 film through a 60-mm objective lens borrowed from my telescope. To correct for the image inversion through the lens, I reversed the polarity of the vertical deflection voltage, and exposed the film for two frames to increase the brightness of the image.

All the SSTV images sent during the STS-51F mission were in some form of color beginning with 128-line frame sequential color and ending (I believe) in Robot 36 format. The green frame produced the best "black and white" image.

I copied a number of images throughout the mission, but was disappointed in many ways with their quality. The Polaroid photos I made served well as Rorschach tests for friends and colleagues at the time:

w0ore_photo.jpg
w0ore_photo.jpg (30.55 KiB) Viewed 11546 times

I used a Turnstile-Reflector antenna in my attic for reception and tape recorded every pass. One particular pass occurred shortly after sunset, and with clear skies overhead I knew the Shuttle would be visible. So I connected a homebuilt "FM Wireless Microphone" transmitter to the output of my 2-meter receiver, started the tape recorder, and walked outside with my parents while carrying a portable FM radio tuned to my low-power transmitter.

For the first few minutes I saw nothing and only heard some local hams improperly trying to contact the Shuttle on it's downlink frequency (145.550 MHz). Suddenly my Father said, "There it is!" while pointing above the tree tops to the northwest. The radio silence was broken a few moments later by this transmission made by astronaut Gordon Fullerton ("Gordo") originating from the "star" I watched flying overhead.

THAT was a life-changing experience for me.

Later SAREX missions brought Packet Radio experiments to several Space Shuttle flights, but SSTV would not be employed again until it was carried aboard the Mir space station, and now the ISS.

73 de John, KD2BD
User avatar
kd2bd
Mad Scientist
 
Posts: 65
Joined: Wed Sep 28, 2016 5:47 am
Location: New Jersey

Re: Decoding SSTV from ISS

Postby kd2bd » Thu Oct 07, 2021 4:03 am

Steve,

The last time I checked, Digi-Key Electronics (https://www.digikey.com/) carried 10.7 MHz monolithic crystal filters suitable for use in NBFM receivers. It's the FM receiver chips, once widely used in cordless telephones, that have become very difficult to find. Even FM discriminator chips that were common for audio detection in TV receivers have become extremely scarce.

But today there are USB dongles, that when paired with SDR software, can receive DC to light (well, almost). Programmable police/fire "scanner" receivers can often copy 2-meter FM signals quite well, too.


73 de John, KD2BD
User avatar
kd2bd
Mad Scientist
 
Posts: 65
Joined: Wed Sep 28, 2016 5:47 am
Location: New Jersey

Re: Decoding SSTV from ISS

Postby Steve Anderson » Thu Oct 07, 2021 3:48 pm

I'd be interested in receiving a SSTV from the ISS, however it's seems the schedule is arranged so they're generally over Russia or the US. I could well be wrong here. I've also tried to find an up-to-date copy of their intended SSTV operations. All the ones I've seen are usually months out of date.

Pointers anyone?

But without a 2m receiver it's all rather academic...though that could change...I'd also have to arrange a method of decoding PD120 (I think) SSTV audio.

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 5376
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: Decoding SSTV from ISS

Postby Klaas Robers » Thu Oct 07, 2021 7:50 pm

Life-changing, indeed. I still remember a sunday afternoon that our Dutch Wubbo Ockels was on flight with the Shuttle. He obtained his amateur licence shortly before his flight, to experience direct communication from the Shuttle to amateurs on the ground. I had my 2-metre rig on the whole afternoon, and every 90 minutes sharp the squelch opened on the signals of the Shuttle. Antenna just a vertical whip and the signals were strong, noise free. There is direct sight! So 5-9 signals.

When the evening fell the sun was down and again the Shuttle came over from west to east. I went outside and saw him clearly illuminated by the sun. I heard the signals with my portable fox-hunting 2-metre receiver and could more or less see the form of the Shuttle. This was really life-changing, because I remember this afternoon clearly. This must have been in the beginning of November 1985, so 36 years ago.

But it also showed me that you need almost no antenna to have good reception of an orbiting spacecraft. The height of ISS is no more than 400 km and you have free sight!
User avatar
Klaas Robers
"Gomez!", "Oh Morticia."
 
Posts: 1656
Joined: Wed Jan 24, 2007 8:42 pm
Location: Valkenswaard, the Netherlands

Re: Decoding SSTV from ISS

Postby kd2bd » Fri Oct 08, 2021 2:19 am

Klaas,

I remember the DP0SL mission as well. If I'm not mistaken, the SpaceLab D-1 mission from October 30 to November 6, 1985 was the last successful flight of Space Shuttle "Challenger".

dp0sl-1.jpg
dp0sl-1.jpg (29.54 KiB) Viewed 11483 times

dp0sl-3.jpg

dp0sl-2.jpg
dp0sl-2.jpg (85.25 KiB) Viewed 11483 times

I had visual sightings of the Shuttle and made some audio recordings of the 2-meter transmissions I copied in New Jersey. These were much stronger than the earlier STS-51 flight of W0ORE, which used lower power and an indoor antenna mounted against one of the Shuttle's windows.

Audio Clip 1
Audio Clip 2
Audio Clip 3

While some of the SSTV activity taking place from the ISS is intended for reception over Russia only, most transmissions take place over the course of several days and can often be copied over most parts of the world. People who receive SSTV images often upload them to the ARISS SSTV Gallery, and judging by the submissions there appears to be a large global following.

One of the SSTV images I copied last year in late December in celebration of the ARISS 20th Anniversary can be seen (and heard) here:


youtu.be/aiQjxsxO36w

73 de John, KD2BD
User avatar
kd2bd
Mad Scientist
 
Posts: 65
Joined: Wed Sep 28, 2016 5:47 am
Location: New Jersey

Re: Decoding SSTV from ISS

Postby kd2bd » Fri Oct 08, 2021 5:47 am

Steve,

The current status and future plans for Amateur Radio operations onboard the ISS can be found here: https://www.ariss.org/current-status-of ... tions.html

73 de John, KD2BD
User avatar
kd2bd
Mad Scientist
 
Posts: 65
Joined: Wed Sep 28, 2016 5:47 am
Location: New Jersey

Re: Decoding SSTV from ISS

Postby Steve Anderson » Fri Oct 08, 2021 1:26 pm

Thanks guys. Now all I have to do is get hold of a 2m receiver and 'wait my turn'. When things look promising I'll travel to another property we have about 160km out of Bangkok which is in an electrically/RF very quiet location...and plenty of space... But first the hardware...

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 5376
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: Decoding SSTV from ISS

Postby Klaas Robers » Fri Oct 08, 2021 6:56 pm

HI HI. It was in the summer of 1985. I was a member of the Dutch examination committee for Radio Amateur Exams. The secretary of the committee told us that they were going to visit Wubbo Ockels to examen him, such that he could have a call during his flight that autumn. He also asked me to join them. Then I said: "Ok, I like to do that, but Wubbo is then doing a true exam!"

We went there, Wubbo was living in Maastricht, the most southern city in NL. At first Wubbo was refusing to do the exam. "I have done so many exams in my life; I am a certified pilot" and more of that. I convinced him that in NL everybody does this exam, even if you are a MSC in electronics. After one hour he admitted: "Ok, give me the paper" and he saw that the questions are not that difficult. He even started to enjoy this exam and the way it was done. Of course he passed it, because "......".

I was happy because at the end he did the exam. Later on he became a far collegue of mine, as a professor at Delft University. He was a nice guy.
User avatar
Klaas Robers
"Gomez!", "Oh Morticia."
 
Posts: 1656
Joined: Wed Jan 24, 2007 8:42 pm
Location: Valkenswaard, the Netherlands

Re: Decoding SSTV from ISS

Postby Steve Anderson » Fri Oct 08, 2021 9:50 pm

I've mentioned before I used to have a UK 'ticket', (G1CLW), which in 1983 was VHF/UHF only, 2m, 70cm and so on. To use the HF bands you needed to sit the Morse exam as well, but I think not so these days. That suited me fine as I was only interested in VHF/UHF line-of-sight communication, especially on 3cm, 10GHz.

Anyway I left the UK in 1989 and relocated to Hong Kong. In the six years I was based there I intended to get a HK license, but I never got around to it. In the meantime my UK license lapsed. Moving here in 1995 I thought about getting a Thai license, but when you learn of all the restrictions and the hassles you have to go through I decided not to bother.

I keep meaning to attend a RAST meeting (Radio Amateur Society of Thailand) which are (or were up until COVID) held annually not for from me. (7-8km). My purpose in going? To ask WHY there are so many restrictions? Not that it's likely anything will change in my lifetime...and the King is the patron of RAST! AND his father held a license too! No, I don't know what his callsign was....just looked it up, HS10A, though some sources say HS1A.

RAST...mostly, 99% plus, in English...

https://www.qsl.net/rast/

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 5376
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Next

Return to SSTV

Who is online

Users browsing this forum: No registered users and 2 guests

cron