BATC Forum

Hi All,

I've recently seen via the AMSAT website some interesting videos about the upcoming mission of Tim Peake to ISS
and the use of Ham TV.

My query was this, I have found via the German supplier Wimo.de, a 40 turn Helix antenna for 13cm (1.5 m long), giving around 18db of gain.

If I was to fit this to my AZ/EL rotator - do you think this would give me sufficent gain and performance to be able to receive the
Ham TV signals from ISS.

If this is the case (and I'm hoping it is) - what additional software package(s) would I need to receive / decode and view the video stream ?

Many thanks and appreciate any advice you can give here...!

Regards /G0TKZ

Officially ( http://www.amsat.org/amsat/ariss/news/HamTV.pdf) that antenna only has half the gain required. However, looking up your call sign tells me you are in Kent. That being the case you are in a good position for overhead passes and you may well have a chance of some success with the Wimo. I live in Bournemouth an use a 1.1M Dish with a Helix feed like this http://www.g6lvb.com/60cm.htm

You have the AZ/EL already, I use orbitron http://www.stoff.pl/ for the tracking.

We had expected that many free to air DVB-S receivers would be able to receive the sound and picture, after the 13cm signal was down converted to 23cm, unfortunately the transmission has a fault that means the DVB tables needed are not in the transport stream. The RX sees the signal but cannot resolve the sound and picture. However, F6DZP has a system that can insert the missing tables.

You need a Technotrend TT S2-1600 or TT S2-3200 these are PCI card receivers. And run the Tutioune software http://www.vivadatv.org/page.php?p=tutioune-en These are becoming harder to find now.

A lot of people are now building the USB solution, Minitiouner http://www.vivadatv.org/viewforum.php?f=80 if you buy the Sharp tuner you don’t need the down converter (but may need a preamp) https://www.batc.org.uk/shop/hardware-and-kits

Info about this is at http://www.batc.org.uk/forum/viewtopic.php?f=15&t=4102 and http://www.batc.org.uk/forum/viewtopic.php?f=15&t=4225

The ARISS Principia website is now up and running at https://principia.ariss.org/ and includes full details of the project including a dashboard showing the ISS position, dishcams and TuTioune monitors from both the Goonhilly receive station and the local school station (currently showing reception of GB3HV).

The ARISS team will be at the science museum for the launch party tomorrow - https://principia.org.uk/ - when the first 4 schools where live contacts will take will be announced.

73

Noel - G8GTZ

ARISS, and the UK Operations Team for ARISS, announced yesterday that the first four ARISS contacts between UK schools and Astronaut Tim Peake have now been confirmed as:-

Between 4th and 10th January 2016 – Sandringham School, St Albans, Hertfordshire.

Between 8th and 14th February 2016 – Royal Masonic School for Girls, Rickmansworth.

Between 15th and 21st February 2016 – Oasis Academy Brightstowe, Bristol.

Between 22nd and 28th February 2016 – City of Norwich Schools, Norwich.

Tim will be operating the amateur radio equipment on the International Space Station as GB1SS and each school will have its own Special Event call sign.

We will not know the exact planned time for each contact until approximately ten days prior to the contact so make sure and follow this site for further announcements, Further information, and details of other possibilities for the remaining schools on the shortlist, will be available early in January 2016.

The reason for posting on the BATC forum is that the HamTV transmitter will be used during these schools contacts for the very first time and live video of the contacts will be available on the 2395 MHz downlink.

73

Noel - G8GTZ

I received ISS HamTv on a 60 cm fixed dish today. I waited for a pass with high (>60 degrees) elevation and pointed the dish towards the highest point of the ISS pass across the sky. Without moving the dish, I received 20 seconds of decoded video.
You can use the free iPhone/iPad app "GoISSWatch" to find out when the next pass is:
Technical Details

The dish was a 60 cm one with an F/D of 0.5. I had previously used it for 10 GHz. I mounted it on a photographic tripod. Any similar dish with and F/D of between 0.33 and 0.6 would probably work.

The feed was a helical feed designed by G3RUH. Details are here http://www.amsat.org/amsat/articles/g3ruh/116.html. Note that the feed is left hand circular polarisation which, when reflected in the dish, gives a right hand circular polarisation to match the ISS transmissions. The later "patch" feed designed and sold for use with AO40 might give slightly better results.

I used a preamp mounted directly behind the feed. This was a G3WDG025 design with nominally NF=0.3dB and Gain=17.5dB, although I'm not sure that mine was that good. Details: http://reocities.com/CapeCanaveral/stat ... reamps.htm.

The output of the preamp was fed through a short cable to a California Amplifier (Type 31909) MMDS downconverter from eBay. This has an LO of 1664 MHz, so gives an output at 731 MHz from the HamTV transmission at 2395 MHz.

I used a 5 MHz-wide 731 MHz band pass filter after the downconverter to filter out very strong local WiFi signals just above 2395 MHz. This was a 4-element filter from my junkbox, and may not be necessary for other locations.

I ran a long cable from the dish to the shack and used a domestic 30 dB satellite line amp to raise the signal level before the tuner.

The MiniTiouner kit with the Sharp tuner works well at 731 MHz, and I ran the MiniTioune software (Version 0.3a) on a desktop Windows 7 PC to decode the video. You can see the result here with the blue line on the left hand side that seems to be transmitted by the transmitter on the ISS while it does not have a camera connected. The Tuner, USB module and PCB for the MiniTiouner are available from the BATC Shop https://www.batc.org.uk/shop/hardware-and-kits. The MiniTiouner software is available from http://www.vivadatv.org/viewtopic.php?f=60&t=441 .

With more gain at 2395 MHz it should be possible to feed the signal from the preamp to the tuner at 2395 MHz, but I had the downconverter available.

Note that the ISS HamTV transmitter is not always active. You can check its status during a pass by looking at https://principia.ariss.org/Dashboard/ and seeing whether it is being received by Goonhilly. Hope that you have as much success as I did. We just need the camera to be connected at the ISS now!

Dave
G8GKQ

Well done Dave, I hope this will encourage others to have a go.
This is great fun

I've been trying from way up north
Not as easy to get a long amount of video even with 3m dish from up here, the antenna pattern on the ISS rolls off very quickly when looking East/Wast.

Got a nice plot of signal this morning with 50deg pass, to the west and east it is very poor but due south extremely good.
I wonder what your plots looked like Colin.... would be interesting to compare to your plot to see how the ISS antenna lobes compare at 50deg vs a direct overhead pass.

Rob
M0DTS

Edit:
Best way to tweak tracking is to monitor sun noise, once you have it stable over a wide tracking angle then the tracking of ISS should be quite good as long as the speed of the tracking is high enough.
I'm using the RTLSDR and SDR# set to USB and 16KHz wide (AGC Off). Then pipe this 'noise' via Virtual audio cable into SpectraVue software and use the continuum mode to plot the level.

As well as the 3.8 mt dish at Goonhilly - http://www.vivadatv.org/tutioune.php?om ... ation_id=1 which is cheating, but a useful check to see if it still transmitting, I have been receiving ISS successfully with a 1.2 mt dish and Yaesu GR5600 rotator on a 20 foot mast in my VERY obstructed back garden.

There are obstructions to the transmit patches by other parts of the ISS as it comes in from the west and are clearly shown on this plot, compared to the gradual degradation when going away from us to the east. Graham G3VZV has written an article in Oscar news on the subject if you want to know more.
The transmitter will be switched off again early next week to allow the KUBIX experiments, which were delayed by the unplanned space walk, to take place but we now understand it will be turned on in time for first ARISS schools contact next Friday but the camera may not be re-commissioned in time

See https://principia.ariss.org/news/ for any updates.

Agree with your comments on sun noise Rob. That is what I will be relying on to set the dish up at the schools as it is a constant alignment source and not pass dependent - the 1600 / 3200 card Tutioune software has a very good noise power program and ideal for tweaking / monitoring the system.

73

Noel - G8GTZ

Although I don't think I have suffered from any problems at this location, I did see some issues which I believe were wifi related at another site so have been playing around with some filters to see if I can remove any potential problems.

Using the 1600 card tiny spectrum analyser program this was the scan centered on 2395 before any filter - pleased to see that channel 1 doesn't seem to get much use!
I then put a big 6 pole inter digital filer in the IF feed to pass 1478 MHz. This is much easier than at 2395 MHz as insertion loss is unimportant and no need to waterproof it plus I suspect any problems will occur with the tuner and not the pre-amp or high level mixer. The results are quite clear to see!
Not sure if it has made any difference at this location but sure it has helped limit the potential impact at other sites.

Noel

Using the equipment described above, I managed solid ISS video reception for 1 minute 25 seconds this morning. Having previously noted the ISS azimuth and elevation at 15 second intervals and calibrated the tripod mount, I manually moved the dish during the pass to track the spacecraft. Not too difficult with a beamwidth of 12 degrees!

Dave
G8GKQ