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Thread: Deep Freeze Ops Antarctic flights

  1. #1
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    Deep Freeze Ops Antarctic flights

    ICE 32 working Deep Freeze Ops on SATCOM 261.725MHz @ 232332 UTC 10:32am AEDST
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  3. #2
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    Nice catch!
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    A short clip.

    My recorder is set to voice activated, so no lengthy blank periods. Also the audio is a little clipped because I'm using a 15kHz filter but the transmissions are 25kHz wide.
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  6. #4
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    wow thats pretty cool, thanks for sharing
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  7. #5
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    Originally Posted by vk3rx
    ICE 32 working Deep Freeze Ops on SATCOM 261.725MHz @ 232332 UTC 10:32am AEDST
    Hi, this is something I might like to have a go at, so what antenna do you have (or I require), is it omni or directional? Any pre-amp reqs? I have a scanner that covers this band so perhaps I'm halfway there?

    Oh, and what satellite is it?
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    I use a 14 element Yagi cut for 240-270MHz pointed at around 173 degrees East, with a masthead preamp. for the same frequency range.

    That said, I used to pick the same signals up with a discone but weak here in SE Oz, hence going to about as good as it gets without going to a commercial SATCOM/TACSAT antenna, which do come up on ebay occasionally.

    Have a listen on 250.450 250.650 and see if you can hear a continuous data transmission (sample on attached audio clip). If you can hear that at reasonable strength, you should hear the output of the transponders. Also check 265.450MHz - at hour +20 minutes a data transmission that lasts for about 60 seconds.

    A frequency set I put together is attached. I have them all in memories, then I scan and lock out the ones that have data on them. Periodically (every few weeks) I go back and unlock them and scan again, in case the data use has ceased.

    You won't hear a lot of voice these days, but the Deep Freeze flights take place between August and March. I heard ICE 32 on Tuesday and ICE 33 yesterday, but I suspect the flights are coming to an end for this season. Info here:


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    It is a bit of a mystery which satellites comms come from, because the satellites can be moved and bandplans changed.

    Pix of my antenna below. Taken from an odd angle, what isn't apparent is that it is pointing to my NE at an elevation angle of 30 degrees. It is also angled at about 45 degrees i.e. halfway between vertical and horiz polarisation because the satellites work with circular polarisation, hence the commercial antennas are helix or RH circular polarisation types.

    Good luck
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    Last edited by vk3rx; 18-02-2017 at 12:08 PM.
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  10. #7
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  12. #8
    Pointing a hor/vert yagi offset to a circular source will result in stronger signal reception than pointing directly at it.
    Youll find the NZCH comms are relayed from the P band transponders off C1
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    Is there a program that decodes the digital data? What is it called?
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  14. #10
    Broadcast data is encrypted theres 15 subchannels on 250.550 ch1. Eleven subchannels for general service message traffic, two subchannels for special intelligence message traffic, and two subchannels for Fleet weather data.
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  15. #11
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    Quite fascinating information. Not the type of thing that you see everyday.

    I was quite tickled by some of the instructions in the document with the airport related information (particularly related to the Antarctic airstrips) -

    Parking – Aircraft are to utilize the parking facilities. If they fail to do so, they will be removed.

    Now, I have seen the tow truck drivers in the CBD removing vehicles from clear ways etc but this takes it to another level entirely. I can just see the flight crew walking out of an Ops Building to find their 'dirty great big aircraft' missing. Where did it go? I can't imagine that there are too many places to hide such aircraft...no trees to hide behind.

    Seriously though it is quite an amazing process maintaining the research stations.

    Regards
    Bernard
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  16. #12
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    Youll find the NZCH comms are relayed from the P band transponders off C1
    Daz FWIW opinion from the U.S. is that the comms are relayed by UFO-F8 @ 172E because they are being copied from the west coast U.S., whereas Optus C1 @ 156E would be below their horizon.

    Also 172E is consistent with where I'm pointing, along with a contact in Brisbane who has a steerable AZ/EL array.

    Bernard: I noted the same

    We can only assume they are talking about lighties parking on the RWY.
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  17. #13
    Thats cool, I know where my antennas are pointed. Ive got Mac Center - mid air comms from F8 and baseops - mid air from C1 and back in the day relays coming off Leasat5 before they moved it

    C1
    F8
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  18. #14
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    What receiver are you using Daz?

    The one I'm using right now is clipping and I need something with a bit broader bandwidth than 15kHz, and I want something standalone, not dongle SDR types.
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  19. #15
    an old frg9600
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  21. #16
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    Operation Deep Freeze Christchurch - Antarctic flights this season again using SATCOM 261.725MHz.

    Last couple of days have been hearing comms. between DEEP FREEZE OPS, MAC CENTER and aircraft.
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  23. #17
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    ICE 32 heard today working MAC CENTER on 263.725MHz SATCOM.

    First time heard this season. I unlocked a bunch of frequencies in the scanner yesterday that previously had data transmissions on them, so this may have been one of them and might explain why I've not heard the ops previously
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