ISS DATV

[VK4KHZ]

The following information was posted on the ARISS website earlier this week;

Ham Video Transmitter Now Transmitting

On Friday May 1, 2015, the Ham Video transmitter on board the Columbus module of the International Space Station was powered on and started transmitting in “Blank Transmission” (BT) mode. In this mode, the transmitter is operated without a camera. The digital TV signal is fully formatted, but the content of the video is black and the content of the audio is at zero level. From a technical perspective, the BT signal is all that is needed for testing and fine-tuning ground stations.

The Ham Video transmitter frequency is 2395 MHz and the symbol rate is 2.0 Ms/sec. The Ham Video transmitter will stay on as long as on-board operations permit. For more details, visit HamTV on the ISS.

When the ground stations are determined to operate reliably, the Ham Video transmitter will be used to enhance ARISS school contacts. Uplink will remain VHF audio only. This operational mode is dubbed ARISS Ham TV.

[VK4KHZ]

I just received full signal lock from the 2395Mhz transmitter during the last ISS pass. This was a low elevation pass for me so I was pretty happy with the result.

[VK4KHZ]

I managed a quick screenshot in the excitement....Nice to see the green LED's lock as the small screen (lower left) turned black.

Regards

Shane VK4KHZ

[VK2AZ]

Nice one Shane,
What equipment are you running?

Hilary
VK2IUW

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[VK4KHZ]

Hi Hilary
I am using a Techno Trend PC Satellite card, TT-Budget S2-1600 as my receiver, a Kuhne MKU LNC 23TM down converter, a small 1.2m kit mesh dish fitted with a 4 turn helix feed (also have a separate 2.4g helix antenna but yet to try it) and the freeware TUTIOUNE analytical software to assist in fine tuning the system.
The dish is steered by an AZ/EL G5500 rotator and steered with SATPC tracking software.
The 2400Mhz TV transmitter on board the ISS is a 10 watt transmitter fed into a patch antenna.
I left the system running overnight and received another two signal locks, on of which was for just over 4 minutes duration.

Regards

Shane VK4KHZ

[VK4KHZ]

The HAMTV transmitter on board the International Space Station has now been turned back on but they have powered it up on 2422Mhz and a symbol rate of 01300ks.
I have not seen any posts alerting anyone of the change yet - or even powering it back up for that matter - however I received several minutes of signal lock and the expected black screen during today's passes.

Regards

Shane VK4KHZ.

[VK1KW]

Would anyone have some info please on the old Galaxy TV grill pack antenna. Mine still has the original feed.
I believe they had a dual bandpass around 2.2 or 2.4 GHz and I think a 500Mhz IF but not sure and cannot find any specific info via google search.

The Galaxy antenna is the one with the square tapered gray support and prime focus with a rectangular reflector on the end.

Any info would be most appreciated here or vk1kw@netspace.net.au

[VK4KHZ]

I noticed during this afternoons pass that the HAMTV transmitter has now been switched back to 2395Mhz and 02000 symbol rate.

This info is posted in the interests of preventing anyone in wasting their time looking for the signal on 2422Mhz....that is if anyone else is even trying.

Regards

Shane VK4KHZ

[VK4KHZ]

I checked during tonight's pass of the ISS to see if the digital TV transmitter (HAMTV) is still transmitting and YES, it is.
It is still transmitting away on 2395mhz (blank screen), symbol rate of 02000. I received around 4 minutes of signal lock off the 1.2m mesh dish.

[VK4KHZ]

I made some changes to my 2.4g 1,2m dish yesterday in order to better balance the load on the G5500 rotator. It was worth the effort as the effects from the small amount of play that is apparent in the rotator gears seems to have been eliminated now. This was a problem which was mainly observed in flip mode and because I had not previously paid too much attention to balancing the load on the rotator I could observe as much as 4 degrees "slop" when the gears meshed during high elevation passes and this would cause short instances of DATV signal loss. The counterweights I used were 2 x 2.5kg weightlifting weights.
The signal I received from todays early morning pass was one of the best to date and despite spending most of yesterday building the antenna mounting frame I think the effort was worth it.

Shane VK4KHZ