Sdr slow scan tv from the iss

Analoguesat

Analoguesat

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I enjoy playing with the sstv transmissions from the space station and I get good results from some pretty simple equipment The ISS doesnt transmit sstv all the time - there are normally 5 or 6 weekends a year when its live. I try to flag details up on this section but also keep an eye on this website

ARISS-SSTV images

So for a dirt cheap sstv system you will need

antenna of some sorts
receiver
cabling & interconnects
some free software.

Some people witth radio gear just feed the audio from their receiver into the sstv software but you dont need that - you can get excellent results with an sdr dongle.

Then you can get something like these pics which Ive received this weekend



3.PNG

4.PNG


Lets look at each of the items we require in turn to build a simple ISS SSTV system
 
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the antenna

The high power transmissions from the ISS make for an easy catch. Almost any tatty old antenna will do Those two pics were actually caught on my 137MHz wxsat turnstile. But Ive also used a 145MHz dipole, and a home built monstrosity made of chocbloc connectors and 2 pieces of garden wire each cut to about 53cm long! All work fine.

As long as the coax run isnt too long you wont need any amplifiers - my system currently doesnt have any amps on it.
 
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the receiver & cables

I use a NooElec nesdr smart sdr dongle for my station. Its not the cheapest dtt dongle out there but its got good stability and its frequency doesnt seem to drift around. Cabling & interconnects - I use satellite grade coax for my antennas simply because Ive got lots of it lying around. Dont let anyone tell you it isnt suitable cabling - it works fine! I use f- to sma- connector adaptors to join the coax to the dongle.

nesd.jpg
 
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Software / computer

You will need a computer of some sort. Im currently running an old cast off i5 laptop with win7 64 bit on it. Under windows dwnload the zadig driver changing software and change the auto installed windows driver to the winusb v6.1.7600.xxx driver (or whatever the latest version is)

zadig.PNG

Obviously this laptop has the software already installed so the driver are the same in the from & to boxes. Zadig can be a bit flaky - you may need to run it a couple of times.

Okn assuming you have that done that successfully download & install the sdr# software. I use version 1361 - its an old version but it works fine with the orbitron satellite tracking software. There are lots of bits to play with, but press the gear icon and make sure the sdr# is recognising the dongle

gear.PNG

THose settings in the box work fine for me - you may need to tweak them a bit.

I set my windows audio sampling rate to 48,000. You may want to experiment. As for the other settings try these to start with

sdr.PNG

Ensure your audio input is set to your appropriate audio source - I use a virtual audio cable here to pipe the audio around the laptop This one which is free. A VAC is required as the sdr# wont take input from the standard windows speaker system

VB-Audio Virtual Apps
 
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Once you are all set up press the little triangle next to the gear wheel and if the sdr deities have been kind to you then you will have some sort of spectrum like this The ISS transmits on 145.8 MHz but its out of range atm

145.PNG


You can use this setup to track signals from cubesats as well, although their tx power is pretty feeble to be honest and you certainly wont get horizon to horizon reception with them like you can with the ISS.


Unless you use a automatic tracking programme like orbitron you will need to manually alter the receive frequency in sdr# - or set a slightly wider bandwidth - have a play and see what works for you.
 
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For basic "where are the satellites" I use wxtrack by David Taylor. The free version is absolutely fine for what we need. If you want to try it download, install then run the options - update keplers command so you get the latest tracking info..

In the setup tab drag & drop the satellites of interest from the available box to the active box. There are 8 banks available - I have one set up for the active NOAAs, Meteor M2 & the ISS, a second bank for some of the active cube sats etc.

Capture.JPG
 
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To get the pretty pictures download the MMSSTV software & install it. Mkae sure its set to the correct audio input the find the rxmode tab, press the auto button & then leave it running.. Once you have it working Leave It Alone!

You can also use this to try sstv from other sources. In your browser go to the websdr.org website and choose one of the on line sources that covers 14230KHz. Leave it running and with a bit of luck you will get some pictures coming in. Quality varies with the stability of the source, noise being received on it etc. You may well find the pictures are "wobbly"!

If you dont get on with MMSSTV you can also try RX-SSTV or others - find one that suits you, I just rcommend MMSTV to start with as its dead easy to get going
 
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