ISS – Russian EVA-33 Comms received using RTL-SDR

Back in April I managed to receive some of the communications downlink from the Russian section of the International Space Station during a EVA/Spacewalk using a FUNCube Dongle Pro+ connected to my discone.

On Monday this week I was alerted to another ambitious EVA being performed by Cosmonauts Fyodor Yurchikhin and debut spacewalker Alexander Misurkin. Details of the EVA can be found here.

The EVA lasted over six hours on the outside of the ISS. The duo conducted a large array of tasks, including the replacement of a fluid flow regulator on the Russian segment’s Zarya module.

As luck would have it the EVA was in progress during several passes over the UK. Unfortunately as I was unaware of it at the time I hadn’t prepared and was stuck in work. I can remotely access my computers and the only receiver I had available was an RTL-SDR which was connected to a random HF long-wire antenna in the loft!

Undeterred I set it recording using SDR# and was surprised at the quality and strength of the signal during the first two passes, so much so I left it connected for the third pass in the evening, again the downlink signal was on 143.625MHz, with the obvious doppler shift.   

I have played back the recorded IQ files and made a video using CamStudio to record directly off the computer screen, the audio and video go out of sync and the frame rate isn’t brilliant.

The joys of RTL-SDR and Taxi MDT Decoding

I have owned and used radio scanners for many years, and loved them as my posts before December 2011 will testify.

In that month I became the proud possessor of a FUNCube Dongle Plus and discovered the joys of software defined radio, since then I purchased a FUNCube Dongle Pro+ and extended my SDR adventures in to the realms of HF and I have several of the insanely cheap RTL2832 based dongles.

As much as loved my scanners there was a major flaw with them, which has been brought into sharp focus now that I have used SDR.

No matter how fast or as sensitive as the scanner is are you are still playing a game of chance. You are limited by the frequency steps, demodulation modes and scanning rate of the receiver and you could zip through the band all day and still miss those elusive signals.

SDR and the waterfall display is a revolution, you can view a portion of the spectrum in real time and actually see the signals, they may be short lived bursts of data and voice, or continuous data transmissions.

The RTL-SDR dongles excel in this respect with their wide sampling rate you can view up to 2MHz of the spectrum at once, the following images show typical waterfalls captured this morning using one of my RTL-SDR dongles.

The first one, shows the cluster of data channels (was the old Vodaphone Paknet system) around 164.2 – 164.4 MHz, a trunking control channel and various data bursts, which are mostly Taxi Mobile Data Terminal (MDT) transmissions.

A little lower down the spectrum and another trunking control channel, a speech conversation, more data bursts and a faint digital channel.

Further up the spectrum into the UHF, a cluster of data transmissions.

Simply moving the cursor on the display and you can hear the transmission, if necessary change the demodulation type, widen or narrow the filter bandwidth, save the frequency. If you capture the IQ file you can then replay it endlessly tweaking and refining until you extract the information you want.

During the weekend I was experimenting and noticed there was lots of data bursts in the 163-168MHz range, I confess that I already knew what most of them were as I have experimented before with a scanner (with a discriminator tap) and Ian Wraith’s Java based Taxi MDT decoder. I decided to reinvestigate them using the RTL-SDR as the receiver.

While many taxi companies still use voice transmissions, many have adopted automated data terminal systems, where the dispatcher sends information about jobs to terminals in the cars, the drivers then can accept jobs, get information and send information back to the dispatcher.

Ian’s decoder which requires the Java runtime environment decodes systems that use the same physical layer as MPT1327 i.e 1200 Hz and 1800 Hz tones transmitted at 1200 bps. The two main systems used in the UK, are the Autocab and Auriga. The Taxi MDT Decoder currenly decodes the Autocab, but the coding for the Auriga system is still an unknown, so just outputs the raw data.

More information about Taxi MDT Decoder can be found here I confess to having one slight niggle with it, often I couldn’t get it to accept sound from the selected input. A work around I found was to first open the Audacity sound editor which I had installed and select the input and start a recording, then opening the decoder seems to make it work!

Ian has also written the excellent DMRDecoder which allows analysis of the DMR digital mode which is becoming more widespread. I intend to post some details soon about decoding digital modes, keep watching.

I created a video showing the Taxi MDT Decoder in action, the quality is pretty dire but you can get the idea, I identify the Auriga as being encrypted, it might be but as nobody on the team knows the protocol yet!

All three Phonesats received and decoded

Yesterday the delayed Antares rocket launched and successfully deployed the three Phonesats

After downloading the TLE http://www.phonesat.org/phonesat.txt this morning and checking the orbital prediction I found as luck would have it that a decent pass would occur when I am home during my lunch break.

So it was out with the 70cm yagi on the tripod fixed pointing south at around 45 degrees elevation and my older FUNCube Dongle on the laptop running SDRSharp (SDR#). It was pleasant sitting on the bench at the top of the garden in the sunshine with the dogs eating my lunch waiting for the pass, and yes at around 14:17BST (13:17UTC) I started to get signals, which came in very strongly.

I recorded the IQ file for later analysis and decoding

I originally tried decoding using Multipsk which I have used extensively to decode APRS from the International Space Station but wasn’t having any luck so I downloaded the free and simple to use Qtmm AFSK1200 Decoder, I simply feed it the audio (using virtual audio cable) and it was soon decoding. However I did have to widen the bandwidth quite a lot to accommodate the full signal. 

The resulting decodes were saved into a text file, here is a selection

15:35:11$ fm KJ6KRW-2 to CQ-0 via TELEM-0 UI  PID=F0
          .5l^lb!<<*”#ljr1N;rq`/H>bN!#!j*83h7os$Ma_0ggo;0tp”AjZcJL_`j`(W^1Y*!(!(S!(&Gkzzzzzzzz!,,q[Ci:G.Ec5e;FD,5.@<Q.%.
15:35:45$ fm KJ6KRW-0 to CQ-0 via TELEM-0 UI  PID=F0
          charging809,0,0,0
15:36:59$ fm KJ6KRW-1 to CQ-0 via TCPIP-0 UI  PID=F0
          .63$uc!<<*”$NL/4)ZTjAR/d3e!#!lB1I-%V’17sg=$r.DW4f*7ks$0O$GWe[Gec]I!5W.F!5a59zzzzzzzz!,,q[Ci:G.Ec5e;FD,5.@<Q.%.

Note due to quite large doppler shift I had to keep replaying the IQ file to adjust for it and the time shown is the time I decoded it, not the time it was received.

Going to the Phonesat website, you can register and submit the packet data which checks and displays the decoded information, which I did.

I had to discard the first and last decimal point in the data to successfully submit it the website

I also managed some good signals using the discone in the loft.

ISS – Russian EVA-32 Comms Received

The International Space Station is currently giving some nice evening passes at the moment, with clear skies and passing close to the crescent moon.

However today they were still undertaking an EVA to add some maintenance, so I programmed in a few frequencies I found on issfanclub.com and had the FUNCube Dongle Pro+ connected to the discone in the loft and really wasn’t expecting much, until a doppler shifting signal appeared around 143.625MHz

Chuffed is an understatement!

Digital SSTV Decoding

I’ve decoded analogue SSTV transmissions before (check out some earlier posts) using the MMSSTV program, but another form of picture transmission is referred to as Digital SSTV.. It isn’t technically slow scan the the SSTV part has stuck because it sends images. In very basic terms it is file transfer using DRM “Digital Radio Mondiale” encoding.

The advantage over analogue SSTV is the use of error correction, with the error correction you can get a perfect image.

This afternoon while the snow was falling outside I had got SDR# with the FCDP+ running and noticed that there was some activitiy on 14.233 Mhz and fired up the EasyPal software and decoded a few images, and made a small video showing one image being received.

As you will observe in the video Easypal actually decoded the image before the end of the transmission because it didn’t need the extra data to error correct because of the very strong clear signal.
 
These were the two nice pictures I decoded today from OE3AWA based in Austria

Interestingly the only other previous D-SSTV image I have received was at the end of December last year, from the same operator!

WSPR using a FUNCube Dongle PRO+

For sometime I have been using my FUNCube Dongle Pro+ SDR as an HF receiver station for WSPR, so. I thought it was about time I posted something.

Introduction
By its very nature radio propagation isn’t totally predictable so someone transmitting can never know exactly where their signal will be received. There is whole science behind radio propagation prediction and amateur radio operators are always on the look out for openings or skip conditions for DX communications. To aid operators a number of propagation beacons exist, usually operating in CW mode transmitting their identification (call sign and location). Some of them use frequency shift keying and some transmit signals in digital modulation modes.

While invaluable operators have to actively receive and monitor these signals and what they really want to know is how their signal is getting out to the rest of the world. This is where the WSPR system comes into its own. The WSPR system uses a protocol which probes these potential propagation paths using low-power QRP transmissions.

WSPR (pronounced “whisper”) stands for “Weak Signal Propagation Reporter” and is a computer program that enables amateur radio stations to participate in a world-wide network of low power propagation beacons. The station transmits beacon signals and receives signals from other stations operating in the same amateur band. These stations then upload ‘spots’ that they receive in real time to a central website wsprnet.org enabling operators to find out where and how strongly they were received, and can view the propagation paths on a map.

It is also possible to operate a receive only station uploading ‘spots’ to the same website, all that is required is a receiver capable of receiving single side band transmissions and feeding the resultant audio into the WSPR program where it is processed. The WSPR program was written by Joe Taylor, K1JT.

These “whisper” signals are often barely audible but their presence can be detected by the WSPR program using signal processing. The WSPR signal uses frequency shift keying (FSK) with a very small shift and a very slow data rate. The signals bandwidth occupied is only about 6 Hz so many stations can operate within the 200Hz WSPR window without interference. WSPR transmissions are encoded to carry a station’s callsign, grid locator, and transmitter power in dBm. The program can decode signals with S/N as low as -28 dB in a 2500 Hz bandwidth.

Each transmission lasts for just under two minutes, and starts at the beginning of each even-numbered minute. Therefore it is vitally important that transmitters and receivers are synchronised, so one of the fundamental pre-requisites of success with WSPR is an accurately-set computer clock. This is achieved by using internet or GPS time synchronisation methods.

Setting Up

This diagram shows the set up I am using at the moment. I have a long-wire antenna connected to the FUNCube Dongle Pro+. I am using SDRSharp (SDR#) to operate the FCDP+ and the resulting audio output is then used as the input into the WSPR program.

I am using SDR# but any suitable SDR program could be used, I have used SDR-Radio and HDSDR but I have found the SDR# program uses less resources on my ageing PC.

Routing the sound output from one program to be the input into another can be problematic and depends on the soundcard and its driver, you might be lucky and have a ‘stereo-mix’ or ‘what-u-hear’ option to use the main sound card output as a recording input, or alternatively you will need to use something like virtual audio cable VAC.

Since the WSPR signal is very narrow band it is desirable that your receiver is accurately calibrated. Most SDR program that support the FUNCube Dongle PRO+ allow a correction setting so that the tuned signal is at the correct frequency, the use of beacons, repeaters, time signals or broadcast stations is an excellent method to set this correction if required.

You will need to download the WSPR program from http://www.physics.princeton.edu/pulsar/K1JT/ the current stable version is WSPR-2.11. The installation is straightforward and when you start the program a window will appear that looks like a command prompt, don’t close this window, it will give important debug messages if there problems. Then the main console window will open along with a window where you set the station parameters.

Don’t worry about the Callsign and Grid locator at the moment, the first thing to do is select the correct audio in source, the rest can be ignored as it relates to a transmitter and I am describing how to set up a receive only station.

Firstly slide the Tx fraction (%) to zero, since you won’t be transmitting and make sure the upload spots is unchecked at the moment, then select the appropriate band you wish to receive. Then set the appropriate dial frequencies in your SDR receiver program, this is shown in the window and your SDR program will need to operate in USB, with a bandwidth of 2500Hz.

The current WSPR dial frequencies are (MHz)
0.136, 0.4742, 1.8366, 3.5926, 5.2872, 7.0386, 10.1387, 14.0956, 18.1046, 21.0946, 24.9246, 28.1246, 50.293, 70.091,144.489

I suggest you turn off any AGC and any filtering in the receiver, uncheck the idle box in WSPR and then wait for the next ‘even’ minute at which point the program should show receiving, alter the sound level so the Rx Noise is ideally around 0dB, but it will work between -10dB and +10dB.

When the two minute interval is over a segment will appear in the waterfall in the top panel and the program will decode any WSPR transmissions received, you will see them as lines in the waterfall as the above image shows. Any successful decodes will appear in the bottom panel.

Once you have got it working, the next thing is to register on the WSPRnet.org website for a SWL callsign, mine is G-SWL10 you will also need to know your grid-locator, you can find this easily using http://f6fvy.free.fr/qthLocator/fullScreen.php

Once registered then putting the data into the station parameters and checking the upload spots will send your spots to the website database, where you can view your spots in the database and on a map, the map at the top shows my spots on one day this week on 20m, getting stations from Australia, the Far East and the US as well as Europe.

Some important things to note are ensure you computer clock is accurately set, if it is wrong you will be out of sync and decodes won’t happen and ensure you are tuned to the correct frequency as you have set the WSPR program otherwise spots will be reported for the wrong band.

It is a fascinating activity and even as just a receiver you are offering a valuable service to amateur operators.

Dongles, Dongles Everywhere!

It is dongle overload at the moment at Châteaux Nerdsville,

Firstly I purchased a new (and improved) RTL-based USB DAB/DVB stick.

Like the FUNCube Dongle Pro it seems the manufacturers of these cheap USB receivers have been hit by the shortage of the Elonics E4000 tuner chips. Up to now the E4000 has been the most desirable tuner to have in the devices as it’s the most capable, giving usable coverage from around 60MHz to 1.7GHz. However Elonics has been liquidated and the intellectual property is up for sale and supply and/or stocks of the E4000 have dwindled. Manufacturers have therefore resorted to different tuners.

One of the alternative devices is the Rafael Micro R820T which has support in Linux drivers so the source code was ported to the rtl-sdr project. Several postings I saw hinted that the device could preform down to around 24MHz (which I have yet to confirm) and was more sensitive, so when I saw a dongle for the grand total of £11 including postage I brought one. It is a Newsky dongle and looks exactly like my previous one.

In the meantime the newly designed FUNCube Dongle Pro PLUS has been in production and lucky customers have been slowly receiving theirs. With over a thousand people in front of me on the waiting list I wasn’t expecting one before the new year, so imagine my surprise when I received an email on Thursday inviting me to buy one, which of course I did without hesitation, and it arrived on Friday! So over the weekend I had chance to toy with it and the RTL-USB device.

The first issue I had was my favoured SDR program SDR-Radio doesn’t yet support the new FCDP+, but support is being worked on for the V2 release. There is support using a new EXT-IO dll for HDSDR but I was keen to reacquaint myself with SDR#.

The SDR# (SDR Sharp) project which has become a popular application and I have used it occasionally with the original FCD. The latest download comes complete with all the necessary drivers and libraries to use with the FCD/FCDP+ and RTL-USB devices, indeed it was quite painless and everything seemed to work straight out the box.

The most obvious new feature of the FCDP+ and one of the main reasons I got one is the extended frequency range. It works down in the LW/MW and HF bands and that is what I have spent most of the weekend doing, picking up a lot of SSB/CW Amateur contest traffic as well as other CB operators. The VHF/UHF preformance seems much better and less prone to noise that the original FCD, but have yet to use it in anger.

Here is a recordings made using the FCDP+ down in 20 meter band

and one made showing reception in the 10 meter band of what appears to be SSB transmissions from America.

The RTL-USB device unfortunately had less use over the weekend playing second fiddle to the much more expensive FCDP+, however I did have some attempts at using it and first impressions are that it is more sensitive than the older version, but that really isn’t much of recommendation as the older device was quite deaf, however it does look quite promising.

This is a recording made of some SSB TX by the RTL-USB in the 70cm band. (The recording that was posted earlier was recorded using the FCD)

FUNCube Dongle PRO+ in production!

Howard is busy assembling and shipping out the first units of the FUNCube Dongle Pro+

I registered my interest early on and am one of the few to have got a confirmation email.

Thank you very much for your interest in the FUNcube Dongle Pro+ that you made on 28 September 2012. This is confirmation that your request is on our waiting list and we will be notifying you by email when we have stock.

I apologise for any delay in receiving this confirmation: the ecommerce software were using doesnt seem to automatically send out responses, so far Ive had to come up with a semi-manual alternative. As I write, there are already a total of 1,233 unique emails on the waiting list, so it may take a few weeks to satisfy the demand.

This was the confirmation for my second attempt at registration, so probably missed out of getting one early. Not sure if it means I am 1233rd or one of the 1233… time will tell, but certainly am very eager to get my hands on one.

At the moment the new PRO+ version won’t work with SDR-Radio my SDR software of choice, but integration is apparently being worked on as we speak. But it seems it is supported by SDR# which I have briefly used.
I am very eager to see the filtering and performance improvements and being able to use on the HF bands, mind you tempted to get another of the RTL based receivers this time with a new tuner following the demise of the E4000. Apparently they work from around 25MHz and are much more sensitive.

FUNcube Dongle PRO+

Ever since I got my FUNCube Dongle Pro last Christmas it has been the main focus of my radio experimentation. I have used it on a number of computers including some quite old not very powerful machines and with different software applications primarily the SDR-Radio and HDSDR suites.

It was a little fiddly to initially set up but I have been impressed with its performance, it has opened my eyes and ears to what is out there on VHF and UHF, much more than I could ever monitor using my scanner receivers. Have a look at my previous postings.

Being SDR, with all decoding being done in software, it is effectively capable of all modes capable with the added advantage of having a variable bandwidth which is useful for data modes.

I have decoded images broadcast from orbit, received transmissions relayed via satellite and even bounced off the surface of the moon! As well as listening to all manner of terrestrial broadcasts.

In a word it is BRILLIANT.

It has its faults, or should I say limitations. It would be nice to have more of the spectrum available at one time and the front end filtering and rejection is troublesome at times. However this is more than made up for by its versatility and performance and it often out preforms my PRO2006 on the same antenna.

On the various forums and social networks it irks me to see people complaining about its performance but then they are usually the same people who go out and purchase a sub £20 RTL2832U based USB FM/DAB/DTV receiver dongle from eBay to use as a SDR and then complain they cannot get it to work or that its performance is lacking. But then that seems to quite common at the moment, everyone expects to just plug it in and it to just work with the minimum of understanding, involvement or experimentation but I digress.

Unfortunately Elonics the suppliers of the tuner chip in the FUNCube Dongle PRO are currently in liquidation and so they have struggled to produce any more units since July this year. This has potentially serious implications for the whole FUNCube educational project as there is no earth based component. Therefore the FUNCube team have instigated a redesign of the receiver and in doing so have increased its functionality and addressed some of the issues. This is the FUNCube Dongle PRO+

 
The new FUNcube Dongle Pro+ offers the following features and enhancements:

  • Full coverage of all amateur bands from 136kHz through HF, 6m, 2m, 4m, 2m, 1.25m, 70cm, 33cm, 23cm (150kHz-240MHz and 420MHz-1.9GHz, 70kHz-150kHz coverage through your software’s NCO offset)
  • 0.5ppm TCXO
  • 192kHz sampling rate
  • Eleven discrete front end filters
  • Super sharp SAW filters on 2m and 70cm

It is expected mid October 2012 and you can register your interest here

The official release of the FUNcube Dongle PRO+ was made during a presentation given to the AMSAT-UKInternational Space Colloquium 2012 on Saturday September 15. You can view the presentation by following these steps:

– Go to http://www.batc.tv/
– Click on “Film Archive”
– Select “AMSAT 2012” in Category box and click on Select Category
– Select “02 – FUNcube PRO-PLUS” in Stream box and click on Select Stream

Or download the whole video of the presentation from
http://www.batc.tv/vod/AMSAT%20session2.flv

Experiments with an SDR4+ and a scanner refurb

Seems the holiday in early June broke the blogging momentum and unfortunately work commitments since and the stresses involved as a major project nears deployment have sapped my time and energy, so not had much to post.

Family commitments too have also eaten into my spare time not leaving me time or inclination to experiment. The FUNCube Dongle and the Ultra-cheap RTL-SDR have been unplugged for several weeks and I am ashamed to say most of my evenings have been sent slumped in front of the TV often nodding off to sleep rather than tinkering away.

That is not to say I have been completely idle! I have spent the last couple of weeks with a Cross Country Wireless SDR4+ receiver courtesy of my younger brother. For a while I have toyed with purchasing one after seeing them at last years Hamfest and have read some decent reviews. The SDR4+ is a HF Software Defined Radio covering 0.85 – 30MHz, the full specifications can be found on their website.

My brother shares a similar interest in radio, probably as he was forced to share a room with me when we were younger and I would subject him to listening to all sorts of strange signals late into the night! Well he decided to purchase one several weeks ago, but was frustrated when it didn’t seem to work. On one of visits to see my Mother I took a cursory look and couldn’t make it work either. To cut a long story short while he went away on holiday I borrowed the unit away to see if I could figure it out.

Following some experimentation and discussions with Chris Moulding on the Cross Country Wireless Yahoo Group turned out the problem was some dodgy USB ports and/or USB leads! The thread can be read at http://uk.groups.yahoo.com/group/cross_country_wireless/message/2136

I strung up a long random-length wire antenna in the loft and have managed to get some decent results on some bands, but interestingly very little on others, probably due to the lack of an ATU. But I have received lots of broadcast AM, some DRM (but not actually decoded) and buckets loads of Amateur transmissions, LSB/USB voice and Morse, RTTY and PSK31 from Europe, and decoded some HF-FAX. Sadly the SDR4+ will soon be off back to it’s rightful owner, but has certainly wetted my appetite.

I have also refurbished my Realistic PRO2022 scanner, as I posted back in 2010 this was my very first scanner and sadly was looking a little bit worse for years of wear. It is still functional, especially for listening to airband but the displays electro-luminescence back light had faded and it was looking a little grubby.

I had already replaced the backlight on my PRO2006, but this was a lot easier due to the display being easily accessible with the simple removal of the front panel, and the EL panel being on flying leads rather than soldered on to a PCB. 

I found a cheap supplier of a suitable EL panel on Ebay and quickly had the new one cut to size and fitted, giving a lovely new blue display.

 The next thing was to clean the grime and grease that was encrusted on the case and knobs, using a small amount of Clit-Bang degreaser and being very careful soon had the case looking almost as good as new!