Satellite experiments with the YAGI

There were a couple of reasonable passes of the ARISSat-1 satellite predicted this afternoon so I decided to try out the nice new InnovAntennas 4 element 144MHz LFA Yagi which my brother won in the prize draw at this years National Hamfest.

Well this is how it arrived, a big cardboard tube that has been sitting in my workshop since October.

Taking everything out the box, lots of metal work, but no instructions!

It was fairly logical to put together, but wasn’t absolutely sure how the folded dipole element went together and the u-shaped end pieces slotted in with no apparent fixings to hold them in place (I assume they are missing along with the instructions) There was also a piece that fitted under the antenna. I am no expert on antenna design so checked the InnovAntenna website but it was no help, lots of graphs and radiation patterns but and not one images of the actual antenna to look at! Looking at a small picture on the Waters and Stanton blog I made a guess as to how it should be put together.

I connected up a bit of coax, and screwed it a short wooden post I had. The end pieces of the folded dipole slipped in and seemed to be fairly secure but probably not brilliant electrically, so will need to secure them properly if I ever use this in anger.

It is lightweight and easy to move about, so I was ready to get going

The satellite passes are from west to east and to the south of my location. So would have to do this at the end of the garden to minimise obstuctions from houses and trees. I would be well away from my normal computer and scanner in the spare bedroom! I decided to use my Realistic PRO-26 hand-held scanner, which is a good performer and has a relatively clean unprocessed audio output (can decode pagers and ascars quite well with it)

I used an old Pentium III laptop running Windows 2000 to capture the audio. I didn’t attempt any decoding of the SSTV directly just captured the wav files so I could edit and process them later. The laptop has dead batteries but could be powered from the summerhouse mains and so with a few extension cables I could have a relatively clear view of the sky and have access to the scanner to adjust levels and could monitor the audio from the laptop!

I experimented with the first pass, at around 13:30 UTC and got a decent signal eventually, but it took a bit of trial and error as the polarisation seems to change during the pass. For the second at 15:14 UTC I set up the camera to record my efforts! The audio in the video is just being picked up by the microphone on the camera so has a lot of background noise, but as you can hear it was at times a fairly strong signal! I had my usual unattended setup going in the spare bedroom and got nothing on either pass!

I have uploaded the two audio files of each pass to Soundcloud

ARISSat1 0611111330 by nerdsville
 
ARISSat1 0611111514 by nerdsville

Here are the images decoded from the audio.. slight sync problems which I suspect is the underpowered laptop – I did have it capturing at 44.8KHz, 32 bit resolution, which was probably an overkill in hindsight!
 



But on the whole it was a fun way to spend the afternoon with some nice results.

Weekend update

Well it was busy weekend and managed to achieve some of what I hoped to.

On Saturday morning I had a trip up to Lincoln to visit the Lincoln Short Wave Club I have for some time been considering taking the plunge to get an Amateur Radio Licence and I’d inquired about any foundation courses and exams they were holding. The secretary contacted me as there is the chance of course in the near future so I popped along to have a chat. It wasn’t the best weekend as they were preparing for the RSGB SSB Field Day Contest but I had chance to make contact. I would have loved to stay around watching/helping them set but I was visiting my family in the afternoon.

During the visit I got chatting to my brother, who has inherited some of interest in radio, and convinced him to lend me his currently disused discone antenna, more on that later.

I also retrieved my old Binatone Worldstar radio which I got one Christmas as a child and got me well and truly hooked on the hobby. It doesn’t quite look at pristine as this one as it was heavily used and abused during my childhood. It lost it’s distinctive world map timezone cover, the handle, antennas and earphone socket were broken and clumsy repaired and it has spent nearly two decades in my late fathers shed/workshop. To say it is looking a little bit worse for wear is an understatement but I hope to restore it, it will never be back to it’s former glory but it would be nice to honour those childhood memories.

On Sunday I did have a good clean up in the workshop, things are packed away in boxes and stored on shelves now, at least I can now get into the workshop without clambering over junk and can find tools now!

During the afternoon I left the scanner and pc monitoring the ARISSat-1 frequency and got this image on the late afternoon pass.

At the time of the pass I was actually up in the loft dimantling the majority of my ‘antenna farm’ (some of them are deaf and not worth the coax) and installing the discone (it is as high as it can go in the loft space). I haven’t been up the loft for a while but was shocked by the amount of stuff up there. I did some rearranging but I really need to have a good clear out.

Well I can report the discone was worthwhile and while I have only used it for a few hours it certainly has improved my reception. I am now hearing the lower power mobile transmissions as well as the more powerful base transmissions from a number of more distant sites. The 70cm/2m amateur bands were also much more active last night and the RAF Waddington Radar is coming through much more cleanly.  

The discone is a Sirio SD 1300 U and I feel my tinkering in the future will be a bit more productive.

More SSTV images from space

After the success earlier in the week have been trying to get some more images from ARISSAT-1 as it passes near or over the UK during the evening. However reception hasn’t been quite as good.

The signal has been dreadful and the passes have been very short lived, not sure if it is the satellite’s performance falling off, interference or just bad luck. The only really decent image I got was another of the project logo. Really would so like to get a decent image from one of the on board cameras, had one almost image but far too much noise to make anything out.

ARISSAT-1

It has been nearly a year since I last posted, and what a year it has been.. but I digress.

Still tinkering with my radio scanners when I get the chance and over the last few days have been satellite hunting.

The ARISSat-1 amateur radio experiment was manually deployed on 3rd August 2011 from the International Space Station during EVA 29. Following on from the earlier SuitSat experiment ARISSat-1 was designed, developed and tested by AMSAT-NA and ARISS volunteers. It’s primary mission is STEM (Science, Technology, Engineering, Mathematics) education around the world.

The idea of the satellite is students should be able to easily receive the 2m FM transmissions as it fly around the globe and use the information in classroom exercises. The transmissions consist of voice message, SSTV images, telemetry and CW beacons.

Certificates will also be issued for SSTV image reception, voice and telemetry reception, CW reception, full SSB telemetry packet reception and Kursk experiment reception. The satellite has four cameras on board that will constantly be taking pictures and sending them to earth using SSTV Robot-36 format in the 2m FM transmission.

The official Web site for the ARISSat-1 project is arissat1.org .

Well I decided I would have a go and using my Realistic PRO-2006 scanner and my homebrew wideband antenna up in the loft have spent the last few evenings trying to pick up the transmissions as it heads over the UK.

The best reception so far was on the 21st August during the second pass of the evening where I got a decent amount of voice transmission and was able to decode a frame of SSTV (pictured above). I put the audio up on to soundcloud.com as well as youtube.

ARISSAT-1 21 Aug 2011 by nerdsville

Unfortunately the satellite has suffered some problems with it’s on board battery and goes silent/resets when it enters the shadow of the earth, which is problematic for reception in Europe as the current passes are occurring late evening.

There are a couple of decent passes this week, so hopefully can get some more intercepts and maybe decode some telemetry using a borrowed Alinco DJ-X10 which has SSB mode. Pass details for your location can be found here

Rebooting a lapsed hobby

My current equipment

Ever since I was old enough to handle a screwdriver and a soldering iron I have had an interest in radio communications and electronics. I spent many a hour in my childhood scanning the Medium and Short Wave bands with various receivers (usually scavenged from family, neighbours or saved from the dump!) I constructed numerous long-wire and other bizarre antennas. I even did a presentation on my hobby for my English Language O-Level exam – I really did confirm my status as a weirdo!

I played with borrowed CB radios and would have loved to progressed into owning one or becoming a proper radio amateur but unfortunately I simply didn’t have the money.

Then the home computer revolution started and my Dragon32 and Tatung Einstein took up most of my time. I left school and went off to University and when I came back home and got a job I spent some of my money on a new fangled radio scanner, a Realistic PRO2022 from Tandy.

A scanner is a radio that covers a wide frequency range, they are controlled my microprocessors and allowing you to listen in to a huge range of different communications including air traffic control, hobbyists (Citizens Band, Amateur radio), security guards, taxi’s and a lot more. Back in the late 80s, and early 90s they also allowed access to the emergency services and the old analogue cellular phones! Connecting it up a computer and using some software you even decode pager messages!

Gradually all the ‘fun’ stuff disappeared, the mobile phones became digital, so did the emergency services. This along with other commitments, such as moving across the country to a new job, getting married and other demands on my time meant the scanner ended up collecting dust in the attic.

Several years ago I briefly dusted it off and brought a couple of other second hand scanners including a Realistic PRO2006 and a brand new Alinco-DJ3X. I also played around with some PMR446 systems, but sadly again they all ended up collecting dust.

Well once again they are out of the boxes and I am having a fun time scanning around for interesting signals, well if you can count listening to the radio microphone at a local church interesting!

I am thinking of buying a CB as it seems to have evolved from the bad old days into something more grown up. Even becoming a DX amateur type system using something called freebanding not legal mind, but then technically using a scanner isn’t!

I am even contemplating taking the Radio Amateur exams and actually achieving a childhood dream, well I do now have access to money and did do an electronics degree!

This time I hope it doesn’t all fizzle out and it is looking more promising as plans are a foot for me to have my own shack and I won’t be spending as much time on my other hobbies next year.